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Review

Lattice-Strained Bimetallic Nanocatalysts: Fundamentals of Synthesis and Structure

by
Yaowei Wang
1,
Huibing Shi
2,
Deming Zhao
2,
Dongpei Zhang
3,*,
Wenjuan Yan
3,* and
Xin Jin
3
1
Shandong Chambroad Zhongcheng Clean Energy, Boxing Economic Development Zone, Boxing County, Binzhou 256500, China
2
Shandong Chambroad Petrochemicals, Boxing Economic Development Zone, Boxing County, Binzhou 256500, China
3
State Key Laboratory of Heavy Oil Processing, College of Chemical Engineering, China University of Petroleum, No. 66 Changjiang West Road, Qingdao 266580, China
*
Authors to whom correspondence should be addressed.
Molecules 2024, 29(13), 3062; https://doi.org/10.3390/molecules29133062
Submission received: 29 December 2023 / Revised: 12 March 2024 / Accepted: 14 March 2024 / Published: 27 June 2024
(This article belongs to the Section Materials Chemistry)
Browse Figures
Review Reports Versions Notes

Abstract

:
Bimetallic nanostructured catalysts have shown great promise in the areas of energy, environment and magnetics. Tunable composition and electronic configurations due to lattice strain at bimetal interfaces have motivated researchers worldwide to explore them industrial applications. However, to date, the fundamentals of the synthesis of lattice-mismatched bimetallic nanocrystals are still largely uninvestigated for most supported catalyst materials. Therefore, in this work, we have conducted a detailed review of the synthesis and structural characterization of bimetallic nanocatalysts, particularly for renewable energies. In particular, the synthesis of Pt, Au and Pd bimetallic particles in a liquid phase has been critically discussed. The outcome of this review is to provide industrial insights of the rational design of cost-effective nanocatalysts for sustainable conversion technologies.

1. Introduction

The development of nanotechnology in recent decades has brought new opportunities for the exploration of new materials that address the issues of fossil fuel consumption and environmental pollution [1,2,3,4,5,6,7,8,9]. Metal catalysts play a central role in sustainable chemistry. Numerous studies have confirmed that the selectivity, activity and stability of bimetallic nanocatalysts are generally superior to those of their corresponding monometallic nanocatalysts in heterogeneous catalysis due to the tunable synergy between the two metallic components [10]. The catalytic synergy for bimetallic nanocatalysts is attributed to the electronic coupling between the two metals as well as geometric manipulation induced by lattice match and mismatch [11].
When the size of a substitutional atom is small, lattice strain leads to structural changes with an atomic position instead of a normal lattice position, resulting in compressive strain. In another case, surface or structural substitution with relatively larger atoms causes tensile strain [12]. Such unique structural properties have two advantages: (i) a high-indexed surface lattice facet with tunable atomic distance; (ii) a high surface–bulk ratio with controllable electronic reconfiguration [11]. By alloying two metals, the formation of heteroatom bonds and geometric effects such as strain due to the change in metal–metal bond lengths cause new electronic structures to appear in bimetallic nanoparticles [13]. So we need to precisely control the structure, size, inter-particle distance, shape, valence state, composition and multi-functionality of metal and metal alloy nanoparticles by preparation methods [14,15]. Catalytic reactions are sensitive to electronic structure and surface atomic arrangement or coordination, which can be controlled by tuning the composition and shape of nanoparticle catalysts [16]. However, several research works have also suggested that the size, shape and composition of particles could be largely irrelevant in comparison to the nature of facets in catalysis; thus, selective high- and low-index facets have been found to selectively promote adsorption, which eventually leads to an effective catalytic reaction [17]. Therefore, the concept of manipulating reduction kinetics of active metal precursors, using step-by-step solution chemistry in a controllable manner to create selective reaction sites on surfaces and the fine design of the space surrounding attached metal complexes, is known as the most popular strategy to achieve selective catalysis on surfaces [18]. Recently, atomically dispersed catalytic materials have shown significant potential in enhancing catalytic activity for certain industrially important reactions. Both experimental and theoretical efforts indicate that atomically dispersed noble metals as catalytic sites on solid supports, in the form of M-O and M-N species, are active sites or at least are involved in catalytic circles [19]. Figure 1 summarizes representative examples for various bimetallic catalysts. In particular, the synthesis of Pt-, Au- and Pd-based bimetallic particles in a liquid phase has been critically discussed.

2. Fundamentals of Nanoparticle Catalysts

2.1. Overview of Synthesis Techniques

Synthetic conditions are key for exposing catalytically active sites. Synthesis conditions may change atomic diffusion, the adsorption energy of surfactants and interaction between nanoparticles. The introduction of a second metal (bimetallic) allows greater flexibility in the design and more tunability in the controllable synthesis of various nano-architectures including nanoparticles, nanowires, nanosheets or nanotubes [10]. Most of the synthetic procedures used to prepare monometallic particles can be applied to bimetallic particle synthesis [20]. In general, three key challenges need to be addressed in the synthesis of bimetallic nanoparticles: (i) control of particle morphology, (ii) control of particle size distribution and (iii) control of nanoparticle composition [21,22]. Sankar [21] summarized four main types of mixing pattern (Figure 2) that can be identified for nanoalloys: core–shell segregated nanoalloys, subcluster segregated nanoalloys, mixed A-B nanoalloys and multishell nanoalloys. The factors influencing their formation include the strength of the bond between the two different metals, the surface energy of the two metals, relative atomic size, electron transfer between the two metals and the stabilizer–ligand used during catalyst synthesis.

2.2. Morphologically Controlled Synthesis

Besson et al. [23] summarized three common methods in the preparation of noble metal catalysts with the catalytic oxidation of various polyols: the impregnation method, the deposition–precipitation method and the sol-immobilization method. Sol-immobilization is a widely used method to prepare gold catalysts [24]. Papers in the literature have summarized eight general synthetic methods [25,26]: molecular beams, chemical reduction, thermal decomposition of transition metal complexes, ion implantation, electrochemical synthesis, radiolysis, sonochemical synthesis and biosynthesis. Several common preparation methods of supported catalysts will be introduced in the following.

2.2.1. Encapsulation Method by the Confinement Effect

Traditional nanocatalysts directly exposing metal active sites will lead to agglomeration and sintering, which will reduce the cycle stability of the catalyst [27]. Metal nanoparticles can be encapsulated in zeolite pores to improve the stability of the catalyst. Besides this, its unique pore structure can provide selective catalysis and improve the selectivity of the target product. Synthesis methods of confined catalysts include the ion exchange method, the impregnation method and the in situ encapsulation method. Among these, the ion exchange and impregnation methods have strict requirements for the properties of raw materials for synthesis. The in situ encapsulation method can synchronize the encapsulation of metal nanoparticles with the formation of zeolite crystals and achieve the accurate anchoring of metal clusters by stabilizing ligands or precursors (Figure 3a). Several noble metal clusters (such as Pt, Pd, Ru and Rh) have been successfully encapsulated in zeolite crystals using ligand stabilization methods and have shown good catalytic activity and selectivity in catalytic reactions [2,28].

2.2.2. Electrochemical Deposition Method

During the electrochemical deposition method, a mixed solution of substrate and metal precursor salt is reduced and deposited by electrochemical methods such as cyclic voltammetry or square wave scanning to the diffusion layer, the electrolyte membrane, or the interface between the diffusion layer and the electrolyte membrane to prepare the required nanomaterials (Figure 3b). Liu et al. [29] reported an example of preparing porous PtCo nanowires by electrochemical deposition. They first deposited Pt and Co nanoparticles on porous anodic aluminum oxide (AAO) membranes in H3BO3 solution and then removed the AAO membranes in an acidic solution to obtain porous PtCo nanowires. Compared with the most advanced Pt/C and PtCo/C catalysts, the prepared porous PtCo alloy nanowires had significantly enhanced electrocatalytic activity for methanol oxidation. Because parameters such as voltage, deposition time, temperature and electric flux are easy to control, the electrochemical deposition method can achieve precise control of the morphology and size of nanoparticles.

2.2.3. Liquid-Phase Chemical Reduction Method

Nanocrystals over supported catalysts can also be obtained from a metal precursor with a reducing agent. This method can precisely control crystal morphology and size by controlling the type, concentration or feeding sequence of reactants, reaction temperature, reaction time, etc. Therefore, it is the main method of industrial production. Lu and coworkers reviewed research progress of the size and shape control of magnetic nanoparticles [27]. Yang found that compared with physical methods and gas-phase strategies, hydrothermal routes are much more easily controlled and can produce nanoarrays in a designed structure and morphology for super-capacitors and catalysts [28]. Several parameters, such as temperature, reaction time, facet bias of capping agents and reduction potential of any of the involved agents, significantly influence the eventual morphology of nanocrystals [10]. Compared with other approaches, wet chemical synthesis methods have been more popular with good potential for implementing environmentally friendly production routes. Green solvents and weak reductive agents are believed to pose less environmental impact during preparation processes [10].

2.2.4. Ultrasound-/Microwave-Assisted Reduction Method

Ultrasound-assisted reduction is a method in which a shock wave can form huge pressure on the surface and channel of a catalyst, discharging gas out of the hole and influxing an active component into the channel, which allows the catalyst component to be distributed in the channel easily. In Liu’s research, hydrogen radicals are excited from plentiful hydroxyls under the action of ultrasound during preparation [30]. Ru-supported Ni-FeLDH catalysts prepared by the ultrasound-assisted method performed a conversion of 100% in N-ethylcarbazole (NEC) hydrogenation and retained excellent catalytic stability in the reaction.
In addition, another method, microwave-assisted synthesis, is where a uniformly mixed precursor reaches a certain high temperature through the absorption of microwave energy, thereby triggering high dispersal. Ni et al. reported the solvent-free microwave-assisted synthesis of supported ruthenium nanocatalysts uniformly supported on non-functional carbon nanotubes (CNT) using Ru3(CO)12 as a precursor, showing 80% conversion and 72% selectivity for cinnamaldehyde hydrogenation [31]. Microwave-assisted synthesis is a simple and promising alternative technology for preparing highly dispersed metal-based catalysts.

2.2.5. Microemulsion Method

The microemulsion method usually refers to two immiscible solvents forming a microemulsion, in which metal ions are nucleated, grown and heat-treated under the action of a surfactant to obtain nanoparticles with a narrow size distribution [32,33,34,35,36,37]. The microemulsion method is an improving method to prepare monodispersed nanoparticles because of the controllable particle size by varying the size of the reversed micelles. The micelle size of the microemulsion and the exchange rate between micelles are important parameters to determine the properties of the nanoparticles [32].
PtCo nanoparticles of uniform size (about 3–4 nm) were synthesized by the simultaneous reduction of H2PtCl6 and Co(NO3)2 with NaBH4 using a W/O microemulsion (water/16.5% polyethylene glycol dodecyl ether/n-heptane) [34]. The cubic phase was formed. PtCo nanoparticles present superparamagnetic behavior and exhibit highly reactive activity to oxalic acid oxidation in H2SO4. Anil et al. prepared microemulsions with different droplet diameters by changing the molar ratio of water to dioctyl sodium sulfosuccinate (AOT) and explored the formation mechanism of nanoparticles in microemulsions in a comprehensive experimental and simulation study [35].
Moreover, nanoparticle catalysts can be used as promoters that are applicable in both homogeneous and heterogeneous phases [38,39]. Nanoparticle catalysis in a homogeneous medium, often referred to as “soluble” NP catalysis, is a classic topic in the field of green chemistry [40]. Initially, the nanoparticles obtained are usually dispersible only in organic solvents, as synthesis procedures usually involve the addition of large amounts of ligands to stabilize particles. Both ligands and solvent are critical for all stages of particle growth and crystallization, impacting composition, size, shape and surface properties of the nanocrystals. Biphasic systems were later developed to tune growth kinetics in a liquid medium [41]. But organic solvents are still the most popular approach to tailor the nanostructures of particles or clusters. For example, oleylamine (OAm) is usually used as a solvent, surfactant and reducing agent, forming metal-OAm complexes at intermediate temperatures (T~250 °C) to control the decomposition rate for generating nanoparticles [42].

3. Synthesis and Properties of Bimetallic Nanoparticles

3.1. Au-Based Bimetallic Nanoparticles

Wet chemical methods are widely used to prepare various Au-based bimetallic catalysts. Recent efforts have been focused on preparing AuPd [43,44,45,46,47], AuPt [48], AuAg [49,50,51] and AuCu [52,53,54] nanoparticles. Typical methods involved in wet chemical approaches include precipitation in the presence of alkaline agents (e.g., NaOH [50]) and in situ deposition induced by introducing reductive agents such as NaBH4 [44,45,46,55], methyl ammonia borane and oleic acid. Structural directing agents such as rGO [46,52], PVP [55,56] and hydroxyethyl starch-poly can be added to control the size and shape of nanoparticles. Typical supports for Au-based bimetallic nanoparticles include graphite, carbon, FTO glass [43,48], TiO2 [53], ZnO [54] and rGO [46,52]. Other approaches, including thermal annealing and plasma reduction, can also be combined to further tune the shape or oxidation states of particles. Au-based bimetallic catalysts are summarized in Table 1.
For AuPd catalysts prepared by thermal annealing, XRD and HRTEM patterns confirm the formation of alloy AuPd particles rather than bulk metals with a miscibility gap. Without a special preparation method, Au and Pd metals can form alloys in almost any proportion while maintaining a face-centered cubic (fcc) structure [44,45]. Fast Fourier transform (FFT) analysis on both sides of the twin boundary shows that most of the particles have decahedral multiple twin structures, which maintain an fcc structure. The typical lattice spacing of the measured (111) plane is between Au (2.35 Å) and Pd (2.25 Å) [44]. Besides this, the lattice spacing of a Pd/Au NP alloy (111) is 0.229 nm, which is in the range of 0.234 nm and 0.223 nm, corresponding to the interplanar spacing of fcc (111) Au and Pd, respectively [45,57]. Because of their superior structural properties, many materials are potentially suitable as excellent substrates to immobilize and to disperse AuPd particles for liquid-phase oxidation, such as g-C3N4 with a large surface area and special p-bonded planar structure [45]. rGO is another type of remarkable support for AuPd catalysts. The corresponding size distribution of AuPd/rGO reveals that their size ranges from 1.6 to 2.8 nm, forming optimized core/shell structures [46]. A core–shell structure is also formed on the outer surface of activated carbon cloth (ACC), with large particles consisting of a gold-rich core covered by small Pd particles with a size of mostly less than 10 nm [58]. Besides this, AuPd alloy also shows a nanoporous dendritic morphology, the growth of which is driven by localized surface plasmon resonance [43].
Table 1. Preparation and morphology of Au-based nanoparticles.
Table 1. Preparation and morphology of Au-based nanoparticles.
NamePreparationMorphologyRef
AuPd/HOPG *Ar, HOPG, UHV, 300 °C“Au core–Pd shell”[47]
AuPd/g-C3N4-N *one-pot deposition reduction method, melamine, sodium borohydridethe lattice edge distance is 0.229 nm, in the range of 0.234 nm and 0.223 nm, respectively[45]
PdCore–AuShell/rGOtwo-step protocol, rGO *, MeAB, Agspherical, varying in size from 1.6 to 2.8 nm[46]
AuPd/activated carbon clothimpregnation method, nitric acid, activated carbon cloth, PdCl2, HAuCl4 [58]
AuPt/FTO glassa new process for efficiently synthesizing supported metal (or metal oxide) NPs using dry plasma reduction at near room temperature under atmosphericAuPtBNP sample shows a finer morphology, where Au sputtered particles produce uniform coverage FTO tight junctions of glass[48]
AuAg/TiO2sequential deposition method, NaOH, urea, hydrogen530 nm[49]
AuAg/HESgraft copolymer reduced method, acrylamide-co-acrylic acid, NaOH, potassium bisulfate [50]
AuCu/rGOdeposition–precipitation method, NaBH4, natural graphite powder, HAuCl4·3H2O, Cu(NO3)2·3H2Ono agglomeration, average size 15 ± 1 nm, surface spacing 0.22 nm[52]
AuCu-ZnO-GrCuAu-ZnO-Gr of two-step synthesis, OLA *ellipsoid, size 18.0 ± 2.0 nm[54]
AuRhhydrogen sacrificial reduction method, alcohol reduction method, sodium borohydride reduction method, PVP *, MNPs, Rh/AuRh (0.22 nm), Au (0.24 nm)[55]
* HOPG: Highly oriented pyrolytic graphite. OLA: oleinic acid. PVP: polyvinyl pyrrolidone. rGO: reduced graphene oxide. g-C3N4-N: graphitic carbon nitride.
AuPt catalysts have also been widely studied. Au ions whose redox potential is higher than that of Pt ions should be more easily reduced than Pt ions. Thus, Au atoms are first gathered to form many tiny clusters which act as seeds for the further aggregation of Pt atoms [59,60]. Jin’s group also found that subtle differences in electronegativity between Pt and Au may also essentially affect the final morphology [60,61]. A large amount of Pt and Au nanoparticles formed instantaneously under the strong reducibility of NaBH4. Besides this, TiO2 provides an electron transfer channel from Au3+ to Pt4+ (Au−Pt interaction), which contributes to the co-reduction of Au and Pt ions, providing a possibility for AuPt alloys. The anisotropic growth of AuPt clusters overcomes strong interfacial forces, leading to the formation of twin boundaries within the bimetallic particles.
AuAg catalysts are one of the Au-based systems that show surprising performance in terms of stability and activity, because of the interaction of Au-Ag rather than a simple mixture of nanoparticles [49,50,51]. Reducibility of Au and Ag during thermal activation was studied by UV–Vis (Figure 4a) [50]. Ag-Au nanoparticles prepared by grafting copolymer produced a single absorption peak at 456 nm that is different from Ag or Au single-metal nanoparticles under the same experimental conditions, indicating that it is not a simple mixture of single-metal nanoparticles. The CO adsorption peak of 2055 cm−1 over Au-Ag/TiO2 catalysts (Figure 4b) perfectly corresponds to the CO-Ag0 species, attesting that Au-Ag atoms have stronger affinity toward O2 and can dissociate it [62]. The optimal activation temperature of 550 °C is sought on a Au-Ag/TiO2 catalyst, based on the particle size effect (negative) and bimetallic interaction effect (positive) [49].
AuCu particles supported on rGO show insignificant agglomeration with an average size of 15 ± 1 nm (Figure 5) [52]. Characterization demonstrates the polycrystalline nature of synthesized nanoparticles. EDS elemental mapping patterns further revealed that Au and Cu elements are uniformly distributed, fully indicating the formation of an Au–Cu alloy without phase segregation. Mechanistic studies for AuCu/ZnO catalyst formation suggest that bimetallic alloy CuAu NPs can cause more photo-generated electrons to transfer to the conduction band of ZnO under simulated sunlight irradiation. Therefore, ZnO can absorb a small part of ultraviolet light in simulated sunlight to generate conduction band electrons (e−) and valence band holes (h+) [54]. As a consequence, electrons that come from CuAu and ZnO accumulate together on the conduction band of ZnO, and these electrons are trapped by dissolved O2 molecules in water as superoxide radical anions and hydroxyl radicals. The oxidized positively charged CuAu NPs and the valence band holes (h+) capture e- from water and colorant molecules to neutralize the positive charge.
The surface plasmon resonance (SPR) band for AuCu/TiO2 catalysts is shown in Figure 6. Au was red-shifted to 545 nm with the addition of Cu2+ on its surface accompanied with a change in color from pink to light red. With the progressive addition of Cu2+, the intensity of the peak at 560–580 nm increased due to a change in shell thickness as well as its composition. A significant change in color and absorption peak was found with an increasing amount of Cu3+. This result indicated the coexistence of two elements (Cu and Au) in one composite, and Au (NS) was entirely encapsulated by Cu (NS), giving rise to a Au core–Cu shell structure.
Other bimetallic Au-based catalysts such as AuRh also show good performance for oxidation. Experimental studies show an increase in the average size of the prepared particles with an increase in Au content, indicating that the Au component was indeed reduced on the surface of the Rh particles. The as-prepared AuRh particles possessed high catalytic activity for H2O2 decomposition. The catalytic activity of the prepared AuRh was closely dependent on its composition. The activity of AuRh nanoparticles with an average size of 2.7 nm was about 3.6 times higher than that of pure Au and Rh monometallic catalysts. Density functional theory (DFT) calculation showed that charged Rh and Au atoms formed via electronic charge transfer effects could be responsible for the high catalytic activity.

3.2. Pt-Based Bimetallic Nanoparticles

In the case of a bimetallic PtFe system, where Pt has a larger lattice distance than Fe, Fe3+ contributes to both galvanic displacement and a lattice-mismatched template for atomic deposition of Pt species. The combinatory effect eventually assists the formation of pyramid-shaped bimetallic clusters with high-surface-index morphologies (Figure 7) [56]. Different synthetic approaches result from different morphologies.
A PtMn system, where the size of the Mn crystal cell is much larger than Pt, however, is completely different from a PtFe system. Ordered structures of PtMn cannot occur due to strong lattice strain at the Pt–Mn interface. Thermal annealing can produce strain-relaxed ordered tetragonal structures [63,64,65,66,67,68,69]. Recent experimental work on lattice-strain-induced structure distortion reveals that a slight increase in Mn content in Pt1Mnx clusters (x: 0.5–2.0) causes Oswald ripening of nanoparticles during self-assembly [63]. The difference in PtFe and PtMn systems suggests that Pt compressive and stretching growth due to lattice strain might follow different mechanisms. In particular, as Mn/Pt content increases from 0.5 to 2.0, bimetallic PtMn clusters evolve from nano-buds to asymmetric cauliflower shapes. Such dramatic cluster morphology reveals that a large mismatch between Pt and Mn with a faster reduction rate of Pt causes simultaneous growth of multiple bud-arms at initial stages. More Mn content stimulates the anisotropic growth of each arm; thus, flower-shaped clusters are achieved (Figure 8). The asymmetric morphology further confirms the hypothesis that the nuclei formed initially immobilize on a solid surface; thus, the whole growing process occurs towards a solvent medium.
The wet synthesis of PtCo as well as PtFe nanocrystals follows a different story due to completely different crystallinity between Pt and Co/Fe metals [70,71]. Sun’s group discovered surprising lattice-dependent activity behavior on PtCo and PtFe nanowires [72]. A wire-shaped morphology can be obtained by injecting Co and Fe carbonyl into Pt(acac)2 solution in a 1-octadecene medium. Due to the strong lattice strain between Pt and Co/Fe metals, disordered fcc structures are obtained for as-prepared nanowires [73]. By thermal treatment, however, fcc evolve to ordered fct structures and exhibit enhanced surface activity for ORR applications.
Compared with PtFe, PtCo and PtMn systems, other bimetallic Pt-based combinations such as PtNi and PtCu also exhibit strain-induced morphology-controlled growth [74]. But it is important to mention that lattice strain in the latter systems is favorable for the selected growth of one specific facet rather than stimulating disordered structures. For example, Ni-assisted Pt nanoparticle growth kinetically accelerates a Pt (100) surface; thus Pt (111) with octahedral crystals is dominant in final samples [75,76,77,78]. Similarly, due to a minor lattice mismatch between Pt and Cu, lattice strain can actually act as the driving force for fcc architecture formation for the generation of (111), (110) and (100) facets [79,80,81,82]. For example, Jiang and Xie [83] synthesized rhombic dodecahedral PtCu3 alloy nanocrystals with a high-energy surface (110) using n-butylamine as a surface regulator. From a crystallographic point of view, the formation of an excavated polyhedron is very difficult due to surface energy minimization and close lattice match between Pt and Cu. It is believed that the strong adsorption of n-butylamine on a PtCu3 (110) surface causes strain reconstruction at the Pt and Cu interface, leading to the growth of a thermodynamically favorable (111) surface while a (110) surface is maintained [83,84]. In other words, the competitive adsorption of amines and minor lattice mismatch might be the intrinsic driving force for the eventual formation of such high-indexed structures.
The classic galvanic displacement technique has also been investigated, coupled with the selective deposition of Cu0 species on an exposed high-energy surface. In particular, the introduction of Br- significantly slows the reduction kinetics of Pt2+ in liquid medium (Table 2, entry 2); thus cubic structures with (100) facets can be generated with the aid of reductive PVP species [85]. In the second stage, the galvanic displacement of Cu0 by Pt2+ etches low-indexed surfaces, which is followed by a final stage of reduction in Cu2+ under hydrothermal conditions, allowing eventual surface reconstruction or strain relaxation to achieve concave structures. Similarly, kinetic control is also used to assist the formation of high-indexed structures for PtCu nanoclusters.
Temperature also plays an important role in the morphology of Pt3Ni nanocrystals. Yang’s group prepared truncated-octahedral Pt3Ni catalysts with (111) as the dominant facet [86]. The length of carbon chains in an amine agent is critical for the formation of a truncated-octahedral structure. Shorter alkane chain amines favor the formation of a (111) surface, suggesting that kinetic rate control to release lattice strain in Pt and Ni system is important. Fang’s team prepared Pt3Ni nanooctahedra using W as the surface modifier [87]. Since it is difficult to slow nucleation time period under solvothermal conditions, W was employed to self-provide stable sources of Pt clusters in the growth stage. The displacement reaction between Pt2+ and W0 controls the thermodynamic growth of Pt3Ni crystals by the difference in the surface energy on each crystallographic face; thus, finely tuned octahedral structures can be obtained. A PtNi octahedral with defects at the corner was prepared using polyol reduction in the presence of poly (diallyldimethylammonium chloride). Element distribution analysis reveals that Pt is richer in corners and edges where lattice strain is strong [88,89,90]. Debe’s team reported novel Pt3Ni7 nanocrystals with fcc lattice parameters of 0.37 nm and 7.5 nm in size. However, such a composition is found to suffer from Ni leaching due to unstable structures above Pt3Ni composition [91].
Table 2. Preparation and morphology of Pt-based nanoparticles.
Table 2. Preparation and morphology of Pt-based nanoparticles.
NamePreparationMorphologyRef
Pt-Fe/Al2O3H2PtCl6·6H2O, cetyltrimethylammonium bromide, butanol, cyclohexane, N2H4 H2O, Al2O3, ethanol, H2PtCl6, FeCl3
80 °C		Polycrystalline structure with high crystallinity[32]
PtCu NPsPlatinum (IV) chloride, copper (II) acetylacetonate, oleylamine, polyvinylpyrrolidone, ethylene glycol
200 °C		Spherical, mean particle size (7.0 ± 0.7) nm[85]
PtCu NWsPlatinum (II) acetylacetonate, cupricchloride, dihydrate, hexacarbonyltungsten, C6H12O6, dodecyl trimethyl ammonium bromide, oleylamine, 1-octadecene, C6H12, CH3COOH, CH3CH2OH, CH3OH
170 °C		Nanowire structure[92]
PtCu/TiO2Pt, Cu, Ar, 500 °CNanotube structure[93]
PtNi/HSNsH2PtCl6·6H2O, Ni(CH3COO)2·4H2O, oleylamine, cetyltrimethyl ammonium chloride, H2SO4
160 °C		hierarchical framework of multilayer structure, uniform octahedral shape, narrow particle size distribution, mean particle size nm 79.8[94]
Pt-Ni/CeO2Ce(NO3)3·6H2O, NaOH, NiCl2,
H2PtCl6, H2/N2
600 °C 		Average particle size 2 nm[95]
Pt–Ni/ZnO-rodZn(NO3)2·6H2O, NaOH, Pt, Pt-acetylacetonate, acetone, Ni(NO3)2·6H2O, ethanol, Ni, H2
500 °C 		Nano-rod structure
3–14 nm		[96]
Pt-Co/TiO2Pt(C5H7O2)2, CoC22H14O4, Ti(OCH2CH2CH2CH3)4
500 °C		Large spherical particles[97]
Different from alloy structures, core–shell morphologies have radial and compressive lattice strain due to lattice mismatch between core and shell materials. Johnson and coworkers predicted trends of more than 132 alloy and core–shell structures for late transition metal systems using DFT [98]. They systematically explored possible segregation energies to determine surface migration trends for binary systems because segregation energy provides a quantitative assessment of segregation behaviors in alloy systems. In general, the core–shell preference from a segregation energy perspective is largely determined by two independent parameters, namely cohesive energy and Wigner–Seitz radius, where the former is considered to be the primary factor. In particular, elements with relatively stronger cohesive energy go to the core part, while metals from the same group with a smaller Wigner–Seitz radius determine core–shell morphologies. Chemical environment also plays a critical role in the formation of core–shell structures. Tsung and coworkers observed the migration of Au from the core to a Pd-rich thin shell due to differences in surface and cohesive energies [99]. Pd has a relatively larger cohesive energy compared with Au. It is therefore more favorable for Pd to migrate to the core part rather than being under-coordinated on the edge [100]. The cohesive energy effect is the main driving force for the formation of PdAu core–shell structures.

4. Conclusions and Outlooks

Based on critical discussion of Au- and Pt-based bimetallic nanocatalysts, it is clear that synthetic conditions are key for controllable morphologies. Temperature, pressure, aging time and concentration of template agents are among the most important factors that contribute to eventual morphologies. However, the following issues remain in current studies:
(i) 
Removal of template agents. Despite beautiful and controllable morphologies owing to the addition of template agents, they are detrimental for catalysis, as residual species of polymers block active sites for surface reactions. Therefore, future efforts should be paid to develop efficient methods to effectively remove template agents, rather than merely focusing on morphological control.
(ii) 
Scale-up synthesis is still missing. Although existing studies have revealed the unique kinetics of the formation of bimetallic nanoparticles, experimental studies on scale-up synthesis are still missing. This might mislead young researchers by an ill-defined yield of nanoparticles per precursor added, as such information is not available in most of the literature.
Nevertheless, more quantitative studies on synthesis, catalysis, plasmonics and magnetic aspects are useful for the further development of nanotechnologies for bimetallic nanomaterials.

Author Contributions

Resources, Y.W.; writing—original draft preparation, H.S. and D.Z. (Deming Zhao); writing—review and editing, D.Z. (Dongpei Zhang) and W.Y.; funding acquisition, X.J. and Y.W. All authors have read and agreed to the published version of the manuscript.

Funding

This work was funded by the National Natural Science Foundation of China, grant numbers 22078365 and 22008262.

Conflicts of Interest

Author Yaowei Wang was employed by the Shandong Chambroad Zhongcheng Clean Energy; Huibing Shi and Deming Zhao were employed by the Shandong Chambroad Petrochemicals. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

References

  1. Dusselier, M.; Van Wouwe, P.; Dewaele, A.; Makshina, E.; Sels, B.F. Lactic acid as a platform chemical in the biobased economy: The role of chemocatalysis. Energy Environ. Sci. 2013, 6, 1415–1442. [Google Scholar] [CrossRef]
  2. Goel, S.; Wu, Z.; Zones, S.I.; Iglesia, E. Synthesis and catalytic properties of metal clusters encapsulated within small-pore (SOD, GIS, ANA) zeolites. J. Am. Chem. Soc. 2012, 134, 17688–17695. [Google Scholar] [CrossRef]
  3. Azadi, O.; Taheri, A.; Babaei, A. New hybrid approach for desulfurization of diesel fuel using an efficient heterogeneous polyoxometalate nanocatalyst. Mater. Chem. Phys. 2023, 297, 127400. [Google Scholar] [CrossRef]
  4. Bodaghifard, M.A.; Hamidinasab, M.; Soleimani, N. Heteropoly acid-based ionic liquid grafted on hybrid nanomaterial for deep oxidative desulfurization of diesel fuel. Res. Chem. Intermed. 2023, 49, 1563–1579. [Google Scholar] [CrossRef]
  5. Ramli, Z.A.C.; Shaari, N.; Saharuddin, T.S.T. Progress and major BARRIERS of nanocatalyst development in direct methanol fuel cell: A review. Int. J. Hydrogen Energy 2022, 47, 22114–22146. [Google Scholar] [CrossRef]
  6. Rezvani, M.A.; Ardeshiri, H.H.; Aghasadeghi, Z. Extractive–Oxidative Desulfurization of Real and Model Gasoline Using (gly)3H[SiW12O40]⊂CoFe2O4 as a Recoverable and Efficient Nanocatalyst. Energy Fuels 2023, 37, 2245–2254. [Google Scholar] [CrossRef]
  7. Yadav, D.; Datta, S.; Saha, S.; Pradhan, S.; Kumari, S.; Gupta, P.K.; Chauhan, V.; Saw, S.K.; Sahu, G. Heterogeneous Nanocatalyst for Biodiesel Synthesis. ChemistrySelect 2022, 7, e202201671. [Google Scholar] [CrossRef]
  8. Astruc, D.; Lu, F.; Aranzaes, J.R. Nanoparticles as recyclable catalysts: The frontier between homogeneous and heterogeneous catalysis. Angew. Chem. Int. Ed. Engl. 2005, 44, 7852–7872. [Google Scholar] [CrossRef]
  9. Yang, Q.; Lu, Z.; Liu, J.; Lei, X.; Chang, Z.; Luo, L.; Sun, X. Metal oxide and hydroxide nanoarrays: Hydrothermal synthesis and applications as supercapacitors and nanocatalysts. Prog. Nat. Sci. Mater. Int. 2013, 23, 351–366. [Google Scholar] [CrossRef]
  10. Dehghan Banadaki, A.; Kajbafvala, A. Recent Advances in Facile Synthesis of Bimetallic Nanostructures: An Overview. J. Nanomater. 2014, 2014, 985948. [Google Scholar] [CrossRef]
  11. Liu, X.; Liu, X. Bimetallic nanoparticles: Kinetic control matters. Angew. Chem. Int. Ed. Engl. 2012, 51, 3311–3313. [Google Scholar] [CrossRef]
  12. Wu, J.; Li, P.; Pan, Y.T.; Warren, S.; Yin, X.; Yang, H. Surface lattice-engineered bimetallic nanoparticles and their catalytic properties. Chem. Soc. Rev. 2012, 41, 8066–8074. [Google Scholar]
  13. An, K.; Somorjai, G.A. Nanocatalysis I: Synthesis of Metal and Bimetallic Nanoparticles and Porous Oxides and Their Catalytic Reaction Studies. Catal. Lett. 2014, 145, 233–248. [Google Scholar]
  14. Cuenya, B.R. Synthesis and catalytic properties of metal nanoparticles: Size, shape, support, composition, and oxidation state effects. Thin Solid Film. 2010, 518, 3127–3150. [Google Scholar] [CrossRef]
  15. Shiju, N.R.; Guliants, V.V. Recent developments in catalysis using nanostructured materials. Appl. Catal. A Gen. 2009, 356, 1–17. [Google Scholar] [CrossRef]
  16. You, H.; Yang, S.; Ding, B.; Yang, H. Synthesis of colloidal metal and metal alloy nanoparticles for electrochemical energy applications. Chem. Soc. Rev. 2013, 42, 2880–2904. [Google Scholar] [CrossRef]
  17. Pal, J.; Pal, T. Faceted metal and metal oxide nanoparticles: Design, fabrication and catalysis. Nanoscale 2015, 7, 14159–14190. [Google Scholar]
  18. Tada, M.; Iwasawa, Y. Advanced chemical design with supported metal complexes for selective catalysis. Chem. Commun. 2006, 27, 2833–2844. [Google Scholar]
  19. Flytzani-Stephanopoulos, M.; Gates, B.C. Atomically dispersed supported metal catalysts. Annu. Rev. Chem. Biomol. Eng. 2012, 3, 545–574. [Google Scholar]
  20. Roucoux, A.; Schulz, J.; Patin, H. Reduced Transition Metal Colloids: A Novel Family of Reusable Catalysts? Chem. Rev. 2002, 102, 3757–3778. [Google Scholar]
  21. Sankar, M.; Dimitratos, N.; Miedziak, P.J.; Wells, P.P.; Kiely, C.J.; Hutchings, G.J. Designing bimetallic catalysts for a green and sustainable future. Chem. Soc. Rev. 2012, 41, 8099–8139. [Google Scholar] [CrossRef]
  22. Graham, J.; Hutchings, C.J.K. Strategies for the Synthesis of Supported Gold Palladium Nanoparticles with Controlled Morphology and Composition. Acc. Chem. Res. 2013, 46, 1759–1772. [Google Scholar]
  23. Besson, M.; Gallezot, P.; Pinel, C. Conversion of biomass into chemicals over metal catalysts. Chem. Rev. 2014, 114, 1827–1870. [Google Scholar] [CrossRef]
  24. Villa, A.; Wang, D.; Veith, G.M.; Vindigni, F.; Prati, L. Sol immobilization technique: A delicate balance between activity, selectivity and stability of gold catalysts. Catal. Sci. Technol. 2013, 3, 3036–3041. [Google Scholar] [CrossRef]
  25. Ferrando, R.; Jellinek, J.; Johnston, R.L. Nanoalloys: From Theory to Applications of Alloy Clusters and Nanoparticles. Chem. Rev. 2008, 108, 845–905. [Google Scholar] [CrossRef]
  26. Helmut Bönnemann, R.M.R. Nanoscopic Metal ParticlesSynthetic Methods and Potential Applications. Eur. J. Inorg. Chem. 2001, 2001, 2455–2480. [Google Scholar] [CrossRef]
  27. Wang, N.; Sun, Q.; Yu, J. Ultrasmall Metal Nanoparticles Confined within Crystalline Nanoporous Materials: A Fascinating Class of Nanocatalysts. Adv. Mater. 2019, 31, e1803966. [Google Scholar] [CrossRef]
  28. Laursen, A.B.; Hojholt, K.T.; Lundegaard, L.F.; Simonsen, S.B.; Helveg, S.; Schuth, F.; Paul, M.; Grunwaldt, J.D.; Kegnaes, S.; Christensen, C.H.; et al. Substrate size-selective catalysis with zeolite-encapsulated gold nanoparticles. Angew. Chem. Int. Ed. Engl. 2010, 49, 3504–3507. [Google Scholar] [CrossRef]
  29. Liu, L.; Pippel, E.; Scholz, R.; Gosele, U. Nanoporous Pt-Co Alloy Nanowires: Fabrication, Characterization, and Electrocatalytic Properties. Nano Lett. 2009, 9, 4352–4358. [Google Scholar] [CrossRef]
  30. Liu, X.; Shi, J.; Bai, X.; Wu, W. Ultrasound-excited hydrogen radical from NiFe layered double hydroxide for preparation of ultrafine supported Ru nanocatalysts in hydrogen storage of N-ethylcarbazole. Ultrason. Sonochem. 2021, 81, 105840. [Google Scholar] [CrossRef]
  31. Ni, X.; Zhang, B.; Li, C.; Pang, M.; Su, D.; Williams, C.T.; Liang, C. Microwave-assisted green synthesis of uniform Ru nanoparticles supported on non-functional carbon nanotubes for cinnamaldehyde hydrogenation. Catal. Commun. 2012, 24, 65–69. [Google Scholar] [CrossRef]
  32. Feng, L.; Liang, J.; Wang, K.; Cao, B.; Song, H. Fe-Promoted Pt-Fe/Al2O3 Catalyst Prepared by Microemulsion Technique for m-Chloronitrobenzene Hydrogenation. Russ. J. Phys. Chem. A 2018, 92, 1279–1284. [Google Scholar] [CrossRef]
  33. Tianimoghadam, S.; Salabat, A. A microemulsion method for preparation of thiol-functionalized gold nanoparticles. Particuology 2018, 37, 33–36. [Google Scholar] [CrossRef]
  34. Solla-Gullón, J.; Gómez, E.; Vallés, E.; Aldaz, A.; Feliu, J.M. Synthesis and structural, magnetic and electrochemical characterization of PtCo nanoparticles prepared by water-in-oil microemulsion. J. Nanoparticle Res. 2009, 12, 1149–1159. [Google Scholar] [CrossRef]
  35. Rajapantulu, A.; Bandyopadhyaya, R. Formation of Gold Nanoparticles in Water-in-Oil Microemulsions: Experiment, Mechanism, and Simulation. Langmuir 2021, 37, 6623–6631. [Google Scholar] [CrossRef] [PubMed]
  36. Pawlonka, J.; Gac, W.; Greluk, M.; Słowik, G. Application of microemulsion method for development of methanol steam reforming Pd/ZnO catalysts. J. Therm. Anal. Calorim. 2016, 125, 1265–1272. [Google Scholar] [CrossRef]
  37. Pal, A. Gold–platinum alloy nanoparticles through water-in-oil microemulsion. J. Nanostructure Chem. 2014, 5, 65–69. [Google Scholar] [CrossRef]
  38. Gnanakumar, E.S.; Ng, W.; Coskuner Filiz, B.; Rothenberg, G.; Wang, S.; Xu, H.; Pastor-Perez, L.; Pastor-Blas, M.M.; Sepulveda-Escribano, A.; Yan, N.; et al. Plasma-Assisted Synthesis of Monodispersed and Robust Ruthenium Ultrafine Nanocatalysts for Organosilane Oxidation and Oxygen Evolution Reactions. ChemCatChem 2017, 9, 4159–4163. [Google Scholar] [CrossRef] [PubMed]
  39. Di, L.; Zhang, J.; Zhang, X. A review on the recent progress, challenges, and perspectives of atmospheric-pressure cold plasma for preparation of supported metal catalysts. Plasma Process. Polym. 2018, 15, 1700234. [Google Scholar] [CrossRef]
  40. Djerdj, I.; Arčon, D.; Jagličić, Z.; Niederberger, M. Nonaqueous synthesis of metal oxide nanoparticles: Short review and doped titanium dioxide as case study for the preparation of transition metal-doped oxide nanoparticles. J. Solid State Chem. 2008, 181, 1571–1581. [Google Scholar] [CrossRef]
  41. Yan, N.; Xiao, C.; Kou, Y. Transition metal nanoparticle catalysis in green solvents. Coord. Chem. Rev. 2010, 254, 1179–1218. [Google Scholar] [CrossRef]
  42. Mourdikoudis, S.; Liz-Marzán, L.M. Oleylamine in Nanoparticle Synthesis. Chem. Mater. 2013, 25, 1465–1476. [Google Scholar] [CrossRef]
  43. Tang, C.; He, Z.; Liu, Y.; He, X.; Chen, G.; Xie, C.; Huang, J. AuPd nanoporous dendrites: High electrocatalytic activity and surface plasmon-enhanced stability for ethanol electrooxidation. Chem. Eng. J. 2023, 453, 139962. [Google Scholar] [CrossRef]
  44. Dimitratos, N.; Villa, A.; Wang, D.; Porta, F.; Su, D.; Prati, L. Pd and Pt catalysts modified by alloying with Au in the selective oxidation of alcohols. J. Catal. 2006, 244, 113–121. [Google Scholar] [CrossRef]
  45. Fang, W.; Deng, Y.; Tang, L.; Zeng, G.; Zhou, Y.; Xie, X.; Wang, J.; Wang, Y.; Wang, J. Synthesis of Pd/Au bimetallic nanoparticle-loaded ultrathin graphitic carbon nitride nanosheets for highly efficientcatalytic reduction of p-nitrophenol. J. Colloid Interface Sci. 2017, 490, 834–843. [Google Scholar] [CrossRef]
  46. Raghavendra, P.; Vishwakshan Reddy, G.; Sivasubramanian, R.; Sri Chandana, P.; Subramanyam Sarma, L. Reduced graphene oxide-supported Pd@Au bimetallic nano electrocatalyst for enhanced oxygen reduction reaction in alkaline media. Int. J. Hydrogen Energy 2018, 43, 4125–4135. [Google Scholar] [CrossRef]
  47. Bukhtiyarov, A.V.; Burueva, D.B.; Prosvirin, I.P.; Klyushin, A.Y.; Panafidin, M.A.; Kovtunov, K.V.; Bukhtiyarov, V.I.; Koptyug, I.V. Bimetallic Pd–Au/Highly Oriented Pyrolytic Graphite Catalysts: From Composition to Pairwise Parahydrogen Addition Selectivity. J. Phys. Chem. C 2018, 122, 18588–18595. [Google Scholar] [CrossRef]
  48. Dao, V.-D.; Choi, Y.; Yong, K.; Larina, L.L.; Shevaleevskiy, O.; Choi, H.-S. A facile synthesis of bimetallic AuPt nanoparticles as a new transparent counter electrode for quantum-dot-sensitized solar cells. J. Power Sources 2015, 274, 831–838. [Google Scholar] [CrossRef]
  49. Sandoval, A.; Delannoy, L.; Méthivier, C.; Louis, C.; Zanella, R. Synergetic effect in bimetallic Au–Ag/TiO2 catalysts for CO oxidation: New insights from in situ characterization. Appl. Catal. A Gen. 2015, 504, 287–294. [Google Scholar] [CrossRef]
  50. Tripathy, T.; Kolya, H.; Jana, S.; Senapati, M. Green synthesis of Ag-Au bimetallic nanocomposites using a biodegradable synthetic graft copolymer; hydroxyethyl starch-g-poly (acrylamide-co-acrylic acid) and evaluation of their catalytic activities. Eur. Polym. J. 2017, 87, 113–123. [Google Scholar] [CrossRef]
  51. Bhukta, A.; Bagarti, T.; Guha, P.; Ravulapalli, S.; Satpati, B.; Rakshit, B.; Maiti, P.; Parlapalli, V.S. Study of Ag induced bimetallic (Au–Ag) nanowires on silicon (5 5 12) surfaces: Experiment and theoretical aspects. Surf. Sci. 2017, 664, 29–37. [Google Scholar] [CrossRef]
  52. Rout, L.; Kumar, A.; Dhaka, R.S.; Reddy, G.N.; Giri, S.; Dash, P. Bimetallic Au-Cu alloy nanoparticles on reduced graphene oxide support: Synthesis, catalytic activity and investigation of synergistic effect by DFT analysis. Appl. Catal. A Gen. 2017, 538, 107–122. [Google Scholar] [CrossRef]
  53. Monga, A.; Bathla, A.; Pal, B. A Cu-Au bimetallic co-catalysis for the improved photocatalytic activity of TiO2 under visible light radiation. Sol. Energy 2017, 155, 1403–1410. [Google Scholar] [CrossRef]
  54. Xie, H.; Ye, X.; Duan, K.; Xue, M.; Du, Y.; Ye, W.; Wang, C. CuAu–ZnO–graphene nanocomposite: A novel graphene-based bimetallic alloy-semiconductor catalyst with its enhanced photocatalytic degradation performance. J. Alloys Compd. 2015, 636, 40–47. [Google Scholar] [CrossRef]
  55. Zhang, H.; Deng, X.; Jiao, C.; Lu, L.; Zhang, S. Preparation and catalytic activities for H2O2 decomposition of Rh/Au bimetallic nanoparticles. Mater. Res. Bull. 2016, 79, 29–35. [Google Scholar] [CrossRef]
  56. Jin, X.; Zhao, M.; Yan, W.; Zeng, C.; Bobba, P.; Thapa, P.S.; Subramaniam, B.; Chaudhari, R.V. Anisotropic growth of PtFe nanoclusters induced by lattice-mismatch: Efficient catalysts for oxidation of biopolyols to carboxylic acid derivatives. J. Catal. 2016, 337, 272–283. [Google Scholar] [CrossRef]
  57. Zhao, G.; Wu, G.; Liu, Y.; He, Y.; Feng, J.; Li, D. Preparation of AuPd/ZnO–CuO for the directional oxidation of glycerol to DHA. Catal. Sci. Technol. 2020, 10, 6223–6234. [Google Scholar] [CrossRef]
  58. Gudarzi, D.; Ratchananusorn, W.; Turunen, I.; Heinonen, M.; Salmi, T. Promotional effects of Au in Pd–Au bimetallic catalysts supported on activated carbon cloth (ACC) for direct synthesis of H2O2 from H2 and O2. Catal. Today 2015, 248, 58–68. [Google Scholar] [CrossRef]
  59. Liu, M.; Lai, L.; Wang, Z.; Jin, X.; Shen, J.; Wang, Y.; Zhang, Q.; Zhang, D.; Sun, Y.; Ning, H.; et al. Catalytic Synthesis of Tartaric Acid from Glucose and Gluconic Acid over AuPt/TiO2 Catalysts: Studies on Catalyst Structure–Performance Dependency. Ind. Eng. Chem. Res. 2023, 62, 6052–6068. [Google Scholar] [CrossRef]
  60. Liu, M.; Jin, X.; Zhang, G.; Xia, Q.; Lai, L.; Wang, J.; Zhang, W.; Sun, Y.; Ding, J.; Yan, H.; et al. Bimetallic AuPt/TiO2 Catalysts for Direct Oxidation of Glucose and Gluconic Acid to Tartaric Acid in the Presence of Molecular O2. ACS Catal. 2020, 10, 10932–10945. [Google Scholar] [CrossRef]
  61. Lai, L.; Liu, M.; Liu, J.; Li, W.; Miao, W.; Sun, Z.; Wang, Z.; Wang, Y.; Shi, H.; Chen, C.; et al. Kinetic Modeling of Glucose Oxidation to Tartaric Acid over Monometallic Pt/TiO2 and Bimetallic AuPt/TiO2 Catalysts: Role of Bimetals on C–H and C–C Cleavages. ACS Sustain. Chem. Eng. 2023, 11, 15851–15864. [Google Scholar] [CrossRef]
  62. Müslehiddinoglu, J.; Vannice, M.A. CO adsorption on supported and promoted Ag epoxidation catalysts. J. Catal. 2003, 213, 305–320. [Google Scholar] [CrossRef]
  63. Jin, X.; Zeng, C.; Yan, W.; Zhao, M.; Bobba, P.; Shi, H.; Thapa, P.S.; Subramaniam, B.; Chaudhari, R.V. Lattice distortion induced electronic coupling results in exceptional enhancement in the activity of bimetallic PtMn nanocatalysts. Appl. Catal. A Gen. 2017, 534, 46–57. [Google Scholar] [CrossRef]
  64. Bossola, F.; Pereira-Hernández, X.I.; Evangelisti, C.; Wang, Y.; Dal Santo, V. Investigation of the promoting effect of Mn on a Pt/C catalyst for the steam and aqueous phase reforming of glycerol. J. Catal. 2017, 349, 75–83. [Google Scholar] [CrossRef]
  65. Nakano, A.; Manabe, S.; Higo, T.; Seki, H.; Nagatake, S.; Yabe, T.; Ogo, S.; Nagatsuka, T.; Sugiura, Y.; Iki, H.; et al. Effects of Mn addition on dehydrogenation of methylcyclohexane over Pt/Al2O3 catalyst. Appl. Catal. A Gen. 2017, 543, 75–81. [Google Scholar] [CrossRef]
  66. Pazos Urrea, M.; Herold, F.; Chen, D.; Rønning, M. Nitrogen-containing carbon nanofibers as supports for bimetallic Pt-Mn catalysts in aqueous phase reforming of ethylene glycol. Catal. Today 2023, 418, 114066. [Google Scholar] [CrossRef]
  67. Roongcharoen, T.; Yang, X.; Han, S.; Sementa, L.; Vegge, T.; Hansen, H.A.; Fortunelli, A. Oxidation and de-alloying of PtMn particle models: A computational investigation. Faraday Discuss 2023, 242, 174–192. [Google Scholar] [CrossRef]
  68. Zhang, R.; Zhao, S.; Mu, R.; Fu, Q. Atmosphere-Dependent Structures of Pt–Mn Bimetallic Catalysts. J. Phys. Chem. C 2020, 124, 17548–17555. [Google Scholar] [CrossRef]
  69. Zheng, Y.; Han, R.; Yang, L.; Yang, J.; Shan, C.; Liu, Q. Revealing opposite behaviors of catalyst for VOCs Oxidation: Modulating electronic structure of Pt nanoparticles by Mn doping. Chem. Eng. J. 2023, 465, 142807. [Google Scholar] [CrossRef]
  70. Huang, J.; Peng, B.; Stracensky, T.; Liu, Z.; Zhang, A.; Xu, M.; Liu, Y.; Zhao, Z.; Duan, X.; Jia, Q.; et al. 1D PtCo nanowires as catalysts for PEMFCs with low Pt loading. Sci. China Mater. 2021, 65, 704–711. [Google Scholar] [CrossRef]
  71. Zhang, C.; Chen, Z.; Yang, H.; Luo, Y.; Qun Tian, Z.; Kang Shen, P. Surface-structure tailoring of Dendritic PtCo nanowires for efficient oxygen reduction reaction. J. Colloid Interface Sci. 2023, 652 Pt B, 1597–1608. [Google Scholar] [CrossRef]
  72. Guo, S.; Li, D.; Zhu, H.; Zhang, S.; Markovic, N.M.; Stamenkovic, V.R.; Sun, S. FePt and CoPt nanowires as efficient catalysts for the oxygen reduction reaction. Angew. Chem. Int. Ed. Engl. 2013, 52, 3465–3468. [Google Scholar] [CrossRef] [PubMed]
  73. Poudyal, N.; Chaubey, G.S.; Nandwana, V.; Rong, C.B.; Yano, K.; Liu, J.P. Synthesis of FePt nanorods and nanowires by a facile method. Nanotechnology 2008, 19, 355601. [Google Scholar] [CrossRef] [PubMed]
  74. Shen, C.; Li, X.; Wei, Y.; Cao, Z.; Li, H.; Jiang, Y.; Xie, Z. PtCo-excavated rhombic dodecahedral nanocrystals for efficient electrocatalysis. Nanoscale Adv. 2020, 2, 4881–4886. [Google Scholar] [CrossRef]
  75. Liu, Z.; Senanayake, S.D.; Rodriguez, J.A. Elucidating the interaction between Ni and CeOx in ethanol steam reforming catalysts: A perspective of recent studies over model and powder systems. Appl. Catal. B Environ. 2016, 197, 184–197. [Google Scholar] [CrossRef]
  76. Wang, S.; He, B.; Tian, R.; Sun, C.; Dai, R.; Li, X.; Wu, X.; An, X.; Xie, X. Ni-hierarchical Beta zeolite catalysts were applied to ethanol steam reforming: Effect of sol gel method on loading Ni and the role of hierarchical structure. Mol. Catal. 2018, 453, 64–73. [Google Scholar] [CrossRef]
  77. Fan, A.; Qin, C.; Zhao, R.; Sun, H.; Sun, H.; Dai, X.; Ye, J.-Y.; Sun, S.-G.; Lu, Y.; Zhang, X. Phosphorus-doping-tuned PtNi concave nanocubes with high-index facets for enhanced methanol oxidation reaction. Nano Res. 2022, 15, 6961–6968. [Google Scholar] [CrossRef]
  78. Hu, M.; Zhang, J.; Zhu, W.; Chen, Z.; Gao, X.; Du, X.; Wan, J.; Zhou, K.; Chen, C.; Li, Y. 50 ppm of Pd dispersed on Ni(OH)2 nanosheets catalyzing semi-hydrogenation of acetylene with high activity and selectivity. Nano Res. 2017, 11, 905–912. [Google Scholar] [CrossRef]
  79. Pei, G.; Liu, X.; Chai, M.; Wang, A.; Zhang, T. Isolation of Pd atoms by Cu for semi-hydrogenation of acetylene: Effects of Cu loading. Chin. J. Catal. 2017, 38, 1540–1548. [Google Scholar] [CrossRef]
  80. Rassolov, A.V.; Krivoruchenko, D.S.; Medvedev, M.G.; Mashkovsky, I.S.; Stakheev, A.Y.; Svitanko, I.V. Diphenylacetylene hydrogenation on a PdAg /Al2O3 single-atom catalyst: An experimental and DFT study. Mendeleev Commun. 2017, 27, 615–617. [Google Scholar] [CrossRef]
  81. Jin, X.; Thapa, P.S.; Subramaniam, B.; Chaudhari, R.V. Kinetic Modeling of Sorbitol Hydrogenolysis over Bimetallic RuRe/C Catalyst. ACS Sustain. Chem. Eng. 2016, 4, 6037–6047. [Google Scholar] [CrossRef]
  82. Liu, W.J.; Xu, Z.; Zhao, D.; Pan, X.Q.; Li, H.C.; Hu, X.; Fan, Z.Y.; Wang, W.K.; Zhao, G.H.; Jin, S.; et al. Efficient electrochemical production of glucaric acid and H2 via glucose electrolysis. Nat. Commun. 2020, 11, 265. [Google Scholar] [CrossRef] [PubMed]
  83. Jia, Y.; Jiang, Y.; Zhang, J.; Zhang, L.; Chen, Q.; Xie, Z.; Zheng, L. Unique excavated rhombic dodecahedral PtCu3 alloy nanocrystals constructed with ultrathin nanosheets of high-energy 110 facets. J. Am. Chem. Soc. 2014, 136, 3748–3751. [Google Scholar] [CrossRef] [PubMed]
  84. Xiong, Y.; Ma, Y.; Lin, Z.; Xu, Q.; Yan, Y.; Zhang, H.; Wu, J.; Yang, D. Facile synthesis of PtCu3alloy hexapods and hollow nanoframes as highly active electrocatalysts for methanol oxidation. CrystEngComm 2016, 18, 7823–7830. [Google Scholar] [CrossRef]
  85. Kalyva, M.; Sunding, M.F.; Gunnæs, A.E.; Diplas, S.; Redekop, E.A. Correlation between surface chemistry and morphology of PtCu and Pt nanoparticles during oxidation-reduction cycle. Appl. Surf. Sci. 2020, 532, 147369. [Google Scholar] [CrossRef]
  86. Wu, J.; Yang, H. Synthesis and electrocatalytic oxygen reduction properties of truncated octahedral Pt3Ni nanoparticles. Nano Res. 2010, 4, 72–82. [Google Scholar] [CrossRef]
  87. Zhang, J.; Yang, H.; Fang, J.; Zou, S. Synthesis and oxygen reduction activity of shape-controlled Pt3Ni nanopolyhedra. Nano Lett. 2010, 10, 638–644. [Google Scholar] [CrossRef] [PubMed]
  88. Radtke, M.; Ignaszak, A. Classical group theory adapted to the mechanism of Pt3Ni nanoparticle growth: The role of W(CO)6 as the “shape-controlling” agent. Phys. Chem. Chem. Phys. 2016, 18, 75–78. [Google Scholar] [CrossRef] [PubMed]
  89. Shin, D.Y.; Shin, Y.-J.; Kim, M.-S.; Kwon, J.A.; Lim, D.-H. Density functional theory–based design of a Pt-skinned PtNi catalyst for the oxygen reduction reaction in fuel cells. Appl. Surf. Sci. 2021, 565, 150518. [Google Scholar] [CrossRef]
  90. Liu, Y.; Chen, H.; Tian, C.; Geng, D.; Wang, D.; Bai, S. One-Pot Synthesis of Highly Efficient Carbon-Supported Polyhedral Pt3Ni Alloy Nanoparticles for Oxygen Reduction Reaction. Electrocatalysis 2019, 10, 613–620. [Google Scholar] [CrossRef]
  91. Debe, M.K.; Steinbach, A.J.; Vernstrom, G.D.; Hendricks, S.M.; Kurkowski, M.J.; Atanasoski, R.T.; Kadera, P.; Stevens, D.A.; Sanderson, R.J.; Marvel, E.; et al. Extraordinary Oxygen Reduction Activity of Pt3Ni7. J. Electrochem. Soc. 2011, 158, B910. [Google Scholar] [CrossRef]
  92. Huang, L.; Zhang, W.; Zhong, Y.; Li, P.; Xiang, D.; Uddin, W.; Li, X.; Wang, Y.-G.; Yuan, X.; Wang, D.; et al. Surface-structure tailoring of ultrafine PtCu nanowires for enhanced electrooxidation of alcohols. Sci. China Mater. 2020, 64, 601–610. [Google Scholar] [CrossRef]
  93. Shahvaranfard, F.; Ghigna, P.; Minguzzi, A.; Wierzbicka, E.; Schmuki, P.; Altomare, M. Dewetting of PtCu Nanoalloys on TiO2 Nanocavities Provides a Synergistic Photocatalytic Enhancement for Efficient H2 Evolution. ACS Appl. Mater. Interfaces 2020, 12, 38211–38221. [Google Scholar] [CrossRef]
  94. Li, S.; Tian, Z.Q.; Liu, Y.; Jang, Z.; Hasan, S.W.; Chen, X.; Tsiakaras, P.; Shen, P.K. Hierarchically skeletal multi-layered Pt-Ni nanocrystals for highly efficient oxygen reduction and methanol oxidation reactions. Chin. J. Catal. 2021, 42, 648–657. [Google Scholar] [CrossRef]
  95. Araiza, D.G.; Arcos, D.G.; Gómez-Cortés, A.; Díaz, G. Dry reforming of methane over Pt-Ni/CeO2 catalysts: Effect of the metal composition on the stability. Catal. Today 2021, 360, 46–54. [Google Scholar] [CrossRef]
  96. Lugo, V.R.; Mondragon-Galicia, G.; Gutierrez-Martinez, A.; Gutierrez-Wing, C.; Rosales Gonzalez, O.; Lopez, P.; Salinas-Hernandez, P.; Tzompantzi, F.; Reyes Valderrama, M.I.; Perez-Hernandez, R. Pt-Ni/ZnO-rod catalysts for hydrogen production by steam reforming of methanol with oxygen. RSC Adv. 2020, 10, 41315–41323. [Google Scholar] [CrossRef]
  97. Tolek, W.; Khruechao, K.; Pongthawornsakun, B.; Mekasuwandumrong, O.; Cadete Santos Aires, F.J.; Weerachawanasak, P.; Panpranot, J. Flame spray-synthesized Pt-Co/TiO2 catalysts for the selective hydrogenation of furfural to furfuryl alcohol. Catal. Commun. 2021, 149, 106246. [Google Scholar] [CrossRef]
  98. Wang, L.L.; Johnson, D.D. Predicted Trends of Core-Shell Preferences for 132 Late Transition-Metal Binary-Alloy Nanoparticles. J. Am. Chem. Soc. 2009, 131, 14023–14029. [Google Scholar] [CrossRef]
  99. Serkov, A.A.; Vol’f, L.A. Oxidation of hemicellulose during the continuous mercerization process. Plenum Publ. Corp. 1985, 16, 329–331. [Google Scholar] [CrossRef]
  100. Akbarzadeh, H.; Abareshi, N.; Kamrani, M. Role of the middle-shell in the stability of three-shell nanoparticles: A molecular dynamics study. Colloids Surf. A Physicochem. Eng. Asp. 2023, 676, 132163. [Google Scholar] [CrossRef]
Molecules 29 03062 g001
Figure 1. Au and Pt composites are the most promising catalysts for the future chemical industry.
Figure 1. Au and Pt composites are the most promising catalysts for the future chemical industry.
Molecules 29 03062 g001
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Figure 2. Schematic representation of some possible mixing patterns in bimetallic systems: (a) core–shell alloys, (b) sub-cluster segregated alloys, (c) ordered and random homogeneous alloys, and (d) multishell alloys. Reproduced with permission from Ref. [21]. Copyright 2012, Royal Society of Chemistry.
Figure 2. Schematic representation of some possible mixing patterns in bimetallic systems: (a) core–shell alloys, (b) sub-cluster segregated alloys, (c) ordered and random homogeneous alloys, and (d) multishell alloys. Reproduced with permission from Ref. [21]. Copyright 2012, Royal Society of Chemistry.
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Figure 3. (a) Schematic of different methods for encapsulating metal within MFI zeolite. Reproduced with permission from Ref. [27]. Copyright 2018, Wiley. (b) Schematic illustration of the fabrication process of nanoporous Pt–Co alloy nanowires. Reproduced with permission from Ref. [29]. Copyright 2009, American Chemical Society.
Figure 3. (a) Schematic of different methods for encapsulating metal within MFI zeolite. Reproduced with permission from Ref. [27]. Copyright 2018, Wiley. (b) Schematic illustration of the fabrication process of nanoporous Pt–Co alloy nanowires. Reproduced with permission from Ref. [29]. Copyright 2009, American Chemical Society.
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Figure 4. (a) UV–VIS spectra of Au, Ag and Ag-Au bimetallic nanocomposites synthesized by the graft copolymer HES-g-poly. Reproduced with permission from Ref. [50]. Copyright 2017, Elsevier. (b) DRIFT spectra of Au–Ag/TiO2 after in situ reduction and CO adsorption. Evolution of the spectra with CO contact time from 0 to 80 min (a–h). Reproduced with permission from Ref. [49]. Copyright 2015, Elsevier.
Figure 4. (a) UV–VIS spectra of Au, Ag and Ag-Au bimetallic nanocomposites synthesized by the graft copolymer HES-g-poly. Reproduced with permission from Ref. [50]. Copyright 2017, Elsevier. (b) DRIFT spectra of Au–Ag/TiO2 after in situ reduction and CO adsorption. Evolution of the spectra with CO contact time from 0 to 80 min (a–h). Reproduced with permission from Ref. [49]. Copyright 2015, Elsevier.
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Figure 5. (a) HAADF-STEM image of Au3-Cu/rGO catalyst; (b–d) EDS mapping of Au3-Cu/rGO catalyst. Reproduced with permission from Ref. [52] Copyright 2017, Elsevier; (e) typical HRTEM images of Pd/Au alloy NPs in the as-obtained Pd/Au@g-C3N4-N(1:1). Reproduced with permission from Ref. [45] Copyright 2017, Elsevier; (f) HRTEM image of Pd@Ag/RGO. Reproduced with permission from Ref. [46]. Copyright 2018, Elsevier; (g) HRSEM images of AuPt-BNP/FTO glass. Reproduced with permission from Ref. [48]. Copyright 2015, Elsevier; (h) TEM image of ZnO nanopyramids. Reproduced with permission from Ref. [54]. Copyright 2015, Elsevier.
Figure 5. (a) HAADF-STEM image of Au3-Cu/rGO catalyst; (b–d) EDS mapping of Au3-Cu/rGO catalyst. Reproduced with permission from Ref. [52] Copyright 2017, Elsevier; (e) typical HRTEM images of Pd/Au alloy NPs in the as-obtained Pd/Au@g-C3N4-N(1:1). Reproduced with permission from Ref. [45] Copyright 2017, Elsevier; (f) HRTEM image of Pd@Ag/RGO. Reproduced with permission from Ref. [46]. Copyright 2018, Elsevier; (g) HRSEM images of AuPt-BNP/FTO glass. Reproduced with permission from Ref. [48]. Copyright 2015, Elsevier; (h) TEM image of ZnO nanopyramids. Reproduced with permission from Ref. [54]. Copyright 2015, Elsevier.
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Figure 6. (a) Emission spectra of monometallic and bimetallic nanocomposites modified TiO2. (b) Effect of different amounts of CuSO4 (0.01 M) deposition onto Au nanospheres for variation in the surface plasmon band, and (c) their respective color changes (increasing Cu2+ ions from A to D). Reproduced with permission from Ref. [53]. Copyright 2017, Elsevier.
Figure 6. (a) Emission spectra of monometallic and bimetallic nanocomposites modified TiO2. (b) Effect of different amounts of CuSO4 (0.01 M) deposition onto Au nanospheres for variation in the surface plasmon band, and (c) their respective color changes (increasing Cu2+ ions from A to D). Reproduced with permission from Ref. [53]. Copyright 2017, Elsevier.
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Figure 7. Lattice-mismatched anisotropic growth of PtFe nanoclusters. HR-TEM images of (a) Pt and (b) PtFe(1) with insets at lower magnification. White bars indicate 5 nm. Reproduced with permission from Ref. [56]. Copyright 2016, Elsevier.
Figure 7. Lattice-mismatched anisotropic growth of PtFe nanoclusters. HR-TEM images of (a) Pt and (b) PtFe(1) with insets at lower magnification. White bars indicate 5 nm. Reproduced with permission from Ref. [56]. Copyright 2016, Elsevier.
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Figure 8. TEM images of bimetallic PtMn catalysts. (a–c) novel nano-bud shaped bimetallic clusters, (d,e) 4 to 8 buds on the PtMn clusters. Anisotropic growth orienting from the surface plane of ordered Pt octahedral or cubic structures. (f) Lattice-strain-induced distorted bimetallic PtMn nanocatalysts. Reproduced with permission from Ref. [63]. Copyright 2017, Elsevier.
Figure 8. TEM images of bimetallic PtMn catalysts. (a–c) novel nano-bud shaped bimetallic clusters, (d,e) 4 to 8 buds on the PtMn clusters. Anisotropic growth orienting from the surface plane of ordered Pt octahedral or cubic structures. (f) Lattice-strain-induced distorted bimetallic PtMn nanocatalysts. Reproduced with permission from Ref. [63]. Copyright 2017, Elsevier.
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Wang, Y.; Shi, H.; Zhao, D.; Zhang, D.; Yan, W.; Jin, X. Lattice-Strained Bimetallic Nanocatalysts: Fundamentals of Synthesis and Structure. Molecules 2024, 29, 3062. https://doi.org/10.3390/molecules29133062

AMA Style

Wang Y, Shi H, Zhao D, Zhang D, Yan W, Jin X. Lattice-Strained Bimetallic Nanocatalysts: Fundamentals of Synthesis and Structure. Molecules. 2024; 29(13):3062. https://doi.org/10.3390/molecules29133062

Chicago/Turabian Style

Wang, Yaowei, Huibing Shi, Deming Zhao, Dongpei Zhang, Wenjuan Yan, and Xin Jin. 2024. "Lattice-Strained Bimetallic Nanocatalysts: Fundamentals of Synthesis and Structure" Molecules 29, no. 13: 3062. https://doi.org/10.3390/molecules29133062

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