Previous Issue
Volume 14, June
 
 

Catalysts, Volume 14, Issue 7 (July 2024) – 23 articles

  • Issues are regarded as officially published after their release is announced to the table of contents alert mailing list.
  • You may sign up for e-mail alerts to receive table of contents of newly released issues.
  • PDF is the official format for papers published in both, html and pdf forms. To view the papers in pdf format, click on the "PDF Full-text" link, and use the free Adobe Reader to open them.
Order results
Result details
Section
Select all
Export citation of selected articles as:
16 pages, 6083 KiB  
Article
New and Facile Preparation Method for Highly Active Iron Oxide Catalysts for CO Oxidation
by Steffen Schlicher, Roland Schoch, Nils Prinz, Mirijam Zobel and Matthias Bauer
Catalysts 2024, 14(7), 416; https://doi.org/10.3390/catal14070416 (registering DOI) - 29 Jun 2024
Abstract
This work presents a new and facile route for the preparation of iron oxide-based catalysts supported on alumina, which enables the targeted synthesis of catalysts with an increased amount of isolated tetrahedrally coordinated iron centers compared to a conventional impregnation procedure, and therefore [...] Read more.
This work presents a new and facile route for the preparation of iron oxide-based catalysts supported on alumina, which enables the targeted synthesis of catalysts with an increased amount of isolated tetrahedrally coordinated iron centers compared to a conventional impregnation procedure, and therefore leads to an increase in activity for CO oxidation reaction. By a multi-step impregnation–calcination protocol, the catalysts were synthesized with iron loadings of between 1 and 10 wt%, and their catalytic activity was then compared with a 10 wt% loaded catalyst prepared by conventional single impregnation. With a loading of 8 wt%, the presented catalysts showed an improved catalytic activity regarding light-off and full conversion temperatures compared to this reference. Through the application of several analytical methods (PXRD, PDF, DRUVS, SEM, XAFS), the improved catalytic activity can be correlated with an increased amount of isolated iron centers and a significantly reduced fraction of agglomerates or particles. Full article
Show Figures

Figure 1

12 pages, 5525 KiB  
Article
Investigation of an Ethanol Electroreforming Cell Based on a Pt1Ru1/C Catalyst at the Anode
by Carmelo Lo Vecchio, Erminia Mosca, Stefano Trocino and Vincenzo Baglio
Catalysts 2024, 14(7), 415; https://doi.org/10.3390/catal14070415 (registering DOI) - 29 Jun 2024
Abstract
The production of H2 from renewable sources represents a crucial challenge for the planet’s future to achieve net zero emissions and store renewable energy. A possible alternative to water electrolysis (WE), which requires high potential (E > 1.48 V) to trigger the [...] Read more.
The production of H2 from renewable sources represents a crucial challenge for the planet’s future to achieve net zero emissions and store renewable energy. A possible alternative to water electrolysis (WE), which requires high potential (E > 1.48 V) to trigger the oxygen evolution reaction (OER), would be alcohol electrochemical reforming (ER), which implies the oxidation of short organic molecules such as methanol or ethanol. In ER, energy must be supplied to the system, but from a thermodynamic point of view, the energy request for the methanol or ethanol oxidation reaction is much lower than that of the OER. To study this process, an in-house 50 wt.% Pt1Ru1/C anodic catalyst was easily synthesized according to the Pt sulphite complex route and the impregnation of a carbon support (Ketjenblack, KB) and a Ru precursor. X-ray diffraction (XRD), X-ray fluorescence (XRF) spectroscopy, and Transmission Electron Microscopy (TEM) were used to characterize the structure, composition, and morphology of the catalyst. It appears that two distinct crystallographic phases of the Pt and Ru nanoparticles were encountered after the synthesis conducted by Ru impregnation. For the electrochemical measurements, ethanol electrooxidation (2 M CH3CH2OH) was studied first in a half cell with a rotating disc electrode (RDE) configuration under acid conditions and then in a direct ethanol electroreforming (or electrolysis) cell, equipped with a proton exchange membrane (PEM) as the electrolyte. The output current density was 0.93 A cm−2 at 1 V and 90 °C in 2 M ethanol. The remarkable current densities obtained in the alcohol electrolyzer at a low voltage are better than the actual state of the art for PEM ethanol ER. Full article
Show Figures

Figure 1

16 pages, 11294 KiB  
Article
Metal-Catalyzed Thermo-Catalytic Decomposition and Continuous Catalyst Generation
by Mpila Makiesse Nkiawete and Randy Lee Vander Wal
Catalysts 2024, 14(7), 414; https://doi.org/10.3390/catal14070414 (registering DOI) - 29 Jun 2024
Abstract
In this study, metal dusting is utilized to initiate a two-stage thermo-catalytic decomposition (TCD) process. Stage 1 starts with metal-catalyzed TCD, and in stage 2 the metal-catalyzed carbon catalyzes additional TCD. TEM is presented of the early- versus late-stage TCD to qualitatively illustrate [...] Read more.
In this study, metal dusting is utilized to initiate a two-stage thermo-catalytic decomposition (TCD) process. Stage 1 starts with metal-catalyzed TCD, and in stage 2 the metal-catalyzed carbon catalyzes additional TCD. TEM is presented of the early- versus late-stage TCD to qualitatively illustrate the second-stage TCD by the metal-catalyzed carbons. Corresponding SEM illustrates differences in growth type and surface density between early versus late reaction times, with backscattered imaging differentiating the first- versus second-stage TCD. TGA supports the microscopic inference of a second carbon phase by the presence of an early (low-temperature) reaction peak, characteristic of low-structure or disordered carbon as the second-stage TCD carbon. Raman analysis confirms that the second-stage carbon deposit is more disordered and unstructured, especially at 1000 °C, supported by the ID/IG and La value changes from 0.068 to 0.936 and 65 nm to 4.7 nm, respectively. To further confirm second-stage TCD occurrence upon pre-catalyzed carbons, two carbon blacks are tested. Exposing a combination of edge and basal or exclusively basal sites for the graphitized form, they afford a direct comparison of TCD carbon nanostructure dependence upon the initial carbon catalyst nanostructure. Pre-oxidation of the stainless-steel wool (SSW) prior to TCD is advantageous, accelerating TCD rates and increasing carbon yield relative to the nascent SSW for an equivalent reaction duration. Full article
(This article belongs to the Section Industrial Catalysis)
Show Figures

Figure 1

9 pages, 522 KiB  
Communication
A Green Synthesis of 3-Selanyl-Isoflavones via Lipase Mediated Selenylation/Cyclization of Enaminones
by Wenbo Kan, Yuming Piao, Wenning Song, Xiaoxuan Chen, Chunyu Wang, Zhi Wang and Lei Wang
Catalysts 2024, 14(7), 413; https://doi.org/10.3390/catal14070413 (registering DOI) - 28 Jun 2024
Viewed by 18
Abstract
Herein, a green biocatalytic approach using lipase as a catalyst has been developed for the synthesis of 3-selanyl-isoflavones through the selenylation/cyclization of 2-hydroxyphenyl enaminones and diphenyl di-selenide under mild conditions. The environmentally friendly method reached high yields of 87–95% in a short time [...] Read more.
Herein, a green biocatalytic approach using lipase as a catalyst has been developed for the synthesis of 3-selanyl-isoflavones through the selenylation/cyclization of 2-hydroxyphenyl enaminones and diphenyl di-selenide under mild conditions. The environmentally friendly method reached high yields of 87–95% in a short time at 30 °C, with 17 examples of 3-selanyl-isoflavones successfully prepared. Furthermore, we have investigated the possible mechanisms underlying this reaction. Full article
13 pages, 1295 KiB  
Article
CO2 Electroreduction by Engineering the Cu2O/RGO Interphase
by Matteo. Bisetto, Sourav Rej, Alberto Naldoni, Tiziano Montini, Manuela Bevilacqua and Paolo Fornasiero
Catalysts 2024, 14(7), 412; https://doi.org/10.3390/catal14070412 (registering DOI) - 28 Jun 2024
Viewed by 103
Abstract
In the present investigation, Cu2O-based composites were successfully prepared through a multistep method where cubic Cu2O nanoparticles (CU Cu2O) have been grown on Reduced Graphene Oxide (RGO) nanosheets. The structural and morphological properties of the materials have [...] Read more.
In the present investigation, Cu2O-based composites were successfully prepared through a multistep method where cubic Cu2O nanoparticles (CU Cu2O) have been grown on Reduced Graphene Oxide (RGO) nanosheets. The structural and morphological properties of the materials have been studied through a comprehensive characterization, confirming the coexistence of crystalline Cu2O and RGO. Microscopical imaging revealed the intimate contact between the two materials, affecting the size and the distribution of Cu2O nanoparticles on the support. The features of the improved morphology strongly affected the electrochemical behavior of the composites, increasing the activity and the faradaic efficiencies towards the electrochemical CO2 reduction reaction process. CU Cu2O/RGO 2:1 composite displayed selective CO formation over H2, with higher currents compared to pristine Cu2O (−0.34 mA/cm2 for Cu2O and −0.64 mA/cm2 for CU Cu2O/RGO 2:1 at the voltage of −0.8 vs. RHE and in a CO2 atmosphere) and a faradaic efficiency of 50% at −0.9 V vs. RHE. This composition exhibited significantly higher CO production compared to the pristine materials, indicating a favorable *CO intermediate pathway even at lower voltages. The systematic investigation on the effects of nanostructuration on composition, morphology and catalytic behavior is a valuable solution for the formation of effective interphases for the promotion of catalytic properties providing crucial insights for future catalysts design and applications. Full article
2 pages, 518 KiB  
Correction
Correction: Aldana et al. Nanocomposite PVDF/TiO2 Photocatalytic Membranes for Micropollutant Removal in Secondary Effluent. Catalysts 2024, 14, 109
by Juan C. Aldana, Marta Pedrosa, Adrián M. T. Silva, Joaquim L. Faria, Juan L. Acero and Pedro M. Álvarez
Catalysts 2024, 14(7), 411; https://doi.org/10.3390/catal14070411 (registering DOI) - 28 Jun 2024
Viewed by 57
Abstract
In the original publication [...] Full article
Show Figures

Figure 12

13 pages, 4607 KiB  
Article
Adjacent Reaction Sites of Atomic Mn2O3 and Oxygen Vacancies Facilitate CO2 Activation for Enhanced CH4 Production on TiO2-Supported Nickel-Hydroxide Nanoparticles
by Praveen Kumar Saravanan, Dinesh Bhalothia, Amisha Beniwal, Cheng-Hung Tsai, Pin-Yu Liu, Tsan-Yao Chen, Hong-Ming Ku and Po-Chun Chen
Catalysts 2024, 14(7), 410; https://doi.org/10.3390/catal14070410 (registering DOI) - 28 Jun 2024
Viewed by 129
Abstract
The catalytic conversion of carbon dioxide (CO2) to methane (CH4) through the “Sabatier reaction”, also known as CO2 methanation, presents a promising avenue for establishing a closed carbon loop. However, the competitive reverse water gas shift (RWGS) reaction [...] Read more.
The catalytic conversion of carbon dioxide (CO2) to methane (CH4) through the “Sabatier reaction”, also known as CO2 methanation, presents a promising avenue for establishing a closed carbon loop. However, the competitive reverse water gas shift (RWGS) reaction severely limits CH4 production at lower temperatures; therefore, developing highly efficient and selective catalysts for CO2 methanation is imperative. In this regard, we have developed a novel nanocatalyst comprising atomic scale Mn2O3 species decorated in the defect sites of TiO2-supported Ni-hydroxide nanoparticles with abundant oxygen vacancies (hereafter denoted as NiMn-1). The as-prepared NiMn-1 catalyst initiates the CO2 methanation at a temperature of 523 K and delivers an optimal CH4 production yield of 21,312 mmol g−1 h−1 with a CH4 selectivity as high as ~92% at 573 K, which is 45% higher as compared to its monometallic counterpart Ni-TiO2 (14,741 mmol g−1 h−1). Physical investigations combined with gas chromatography analysis corroborate that the exceptional activity and selectivity of the NiMn-1 catalyst stem from the synergistic cooperation between adjacent active sites on its surface. Specifically, the high density of oxygen vacancies in Ni-hydroxide and adjacent Mn2O3 domains facilitate CO2 activation, while the metallic Ni domains trigger H2 splitting. We envision that the obtained results pave the way for the design of highly active and selective catalysts for CO2 methanation. Full article
Show Figures

Figure 1

17 pages, 3523 KiB  
Article
A Preliminary Assessment of Sorption-Enhanced Methanol Synthesis in a Fluidized Bed Reactor with Selective Addition/Removal of the Sorbent
by Miguel Menéndez, Raúl Ciércoles, Javier Lasobras, Jaime Soler and Javier Herguido
Catalysts 2024, 14(7), 409; https://doi.org/10.3390/catal14070409 - 28 Jun 2024
Viewed by 120
Abstract
Methanol synthesis from CO2 can be made in the presence of a sorbent to increase the achievable yield. If the fresh sorbent is continuously fed to a fluidized bed and separated from the catalyst bed by segregation, a steady-state operation can be [...] Read more.
Methanol synthesis from CO2 can be made in the presence of a sorbent to increase the achievable yield. If the fresh sorbent is continuously fed to a fluidized bed and separated from the catalyst bed by segregation, a steady-state operation can be achieved. The objective of the present work is to provide insight on the suitable operating conditions for such a fluidized bed reactor system. For this, a conventional CuO/ZnO/Al2O3 was selected as the catalyst, and the SiOLITE® zeolite was selected as the sorbent. Different particle sizes were used to be tested in various proportions to perform the fluidized bed segregation study. The fluid dynamics and segregation of the catalyst–sorbent binary mixtures were the most critical points in the development of this proof of concept. A good bed segregation with a mixing index of 0.31 was achieved. This fact favors the correct operation of the system with the continuous addition of adsorbent, which had hardly any catalyst losses during the tests carried out, achieving a loss of 0.005 g/min under optimal conditions. Continuous feeding and removal of sorbent with a low loss of catalyst was observed. Reactor simulations with MATLAB provided promising results, indicating that the addition of sorbent considerably improves the methanol yield under some operating conditions. This makes it more viable for industrial scaling, since it allows us to considerably reduce the pressure used in the methanol synthesis process or to increase the yield per step, reducing the recirculation of unconverted reactants. Full article
(This article belongs to the Special Issue Fluidizable Catalysts for Novel Chemical Processes)
Show Figures

Graphical abstract

31 pages, 9448 KiB  
Article
Photocatalytic 4-Nitrophenol Reduction by Hydrothermally Synthesized Mesoporous Co- and/or Fe-Substituted Aluminophosphates
by B. M. Swetha, Rajeev Kumar, Anupama A. V., Sarvesh Kumar, Fei Yan and Balaram Sahoo
Catalysts 2024, 14(7), 408; https://doi.org/10.3390/catal14070408 - 28 Jun 2024
Viewed by 129
Abstract
Mesoporous cobalt- and/or iron-substituted aluminophosphates were synthesized by a hydrothermal method, followed by pyrolysis and calcination. The substitution of the transition metal elements modified the electronic properties of the samples and the accompanying surface characteristics. The samples showed tunable catalytic activity through the [...] Read more.
Mesoporous cobalt- and/or iron-substituted aluminophosphates were synthesized by a hydrothermal method, followed by pyrolysis and calcination. The substitution of the transition metal elements modified the electronic properties of the samples and the accompanying surface characteristics. The samples showed tunable catalytic activity through the substitution of Fe and/or Co. We have demonstrated that the light-induced photocatalytic 4-nitrophenol reduction reaction can be enhanced through the substitution of Fe and/or Co in aluminophosphates. The induction time associated with the three different types of samples, observed due to the influence of the substituents, allows us to understand the mechanism of the 4-nitrophenol reduction process in our samples. Our work solves the issue associated with the origin of induction time and the enhancement of the catalytic activity of mesoporous aluminophosphates in the 4-nitrophenol reduction reaction through a controlled modification of the electronic properties. Full article
(This article belongs to the Section Photocatalysis)
Show Figures

Figure 1

3 pages, 1865 KiB  
Editorial
Exclusive Papers of the Editorial Board Members and Topical Advisory Panel Members of Catalysts in Section “Catalysis in Organic and Polymer Chemistry”
by Kotohiro Nomura, Raffaella Mancuso, Zhengguo Cai, Samuel Dagorne, Moris S. Eisen, Luca Gonsalvi, Martin Kotora, Bun Yeoul Lee, Shaofeng Liu, Luísa Margarida Martins, Takeshi Ohkuma, Armando Pombeiro, Fabio Ragaini, Carl Redshaw, Marc Visseaux, Zongquan Wu, Hiroto Yoshida and Masamichi Ogasawara
Catalysts 2024, 14(7), 407; https://doi.org/10.3390/catal14070407 - 27 Jun 2024
Viewed by 243
Abstract
Herein, I would like to provide an overview of this Special Issue, published in the Organic and Polymer Chemistry Section of Catalysis, comprising contributions from 18 of the journal’s Editorial Board Members [...] Full article
14 pages, 986 KiB  
Article
Study on Novel SCR Catalysts for Denitration of High Concentrated Nitrogen Oxides and Their Reaction Mechanisms
by Bo Yu, Xingyu Liu, Shufeng Wu, Heng Yang, Shuran Zhou, Li Yang and Fang Liu
Catalysts 2024, 14(7), 406; https://doi.org/10.3390/catal14070406 - 27 Jun 2024
Viewed by 137
Abstract
With the rapid development of industrialization, the emission of nitrogen oxides (NOx) has become a global environmental issue. Uranium is the primary fuel used in nuclear power generation. However, the production of uranium, typically based on the uranyl nitrate method, usually [...] Read more.
With the rapid development of industrialization, the emission of nitrogen oxides (NOx) has become a global environmental issue. Uranium is the primary fuel used in nuclear power generation. However, the production of uranium, typically based on the uranyl nitrate method, usually generates large amounts of nitrogen oxides, particularly NO2, with concentrations in the exhaust gas exceeding 10,000 ppm. High concentrations of nitrogen dioxide are also produced during silver electrolysis processing and the treatment of waste electrolyte solutions. Traditional V-W/TiO2 NH3-SCR catalysts typically exhibit high catalytic activity at temperatures ranging from 300 to 400 °C, under conditions of low NOx concentrations and high gas hourly space velocity. However, their performance is not satisfying when reducing high concentrations of NO2. This study aims to optimize the traditional V-W/TiO2 catalysts to enhance their catalytic activity under conditions of high NO2 concentrations (10,000 ppm) and a wide temperature range (200–400 °C). On the basis of 3 wt% Mo/TiO2, various loadings of V2O5 were selected, and their catalytic activities were tested. Subsequently, the optimal ratios of active component vanadium and additive molybdenum were explored. Simultaneously, doping with WO3 for modification was selected in the V-Mo/TiO2 catalyst, followed by activity testing under the same conditions. The results show that: the NOx conversion rates of all five catalysts increase with temperature at range of 200–400 °C. Excessive loading of MoO3 decreased the catalytic performance, with 5 wt% being the optimal loading. The addition of WO3 significantly enhanced the low-temperature activity of the catalysts. When the loadings of WO3 and MoO3 were both 3 wt%, the catalyst exhibited the best denitrification performance, achieving a NOx conversion rate of 98.8% at 250 °C. This catalyst demonstrates excellent catalytic activity in reducing very high concentration (10,000 ppm) NO2, at a wider temperature range, expanding the temperature range by 50% compared to conventional SCR catalysts. Characterization techniques including BET, XRD, XPS, H2-TPR, and NH3-TPD were employed to further study the evolution of the catalyst, and the promotional mechanisms are explored. The results revealed that the proportion of chemisorbed oxygen (Oα) increased in the WO3-modified catalyst, exhibiting lower V reduction temperatures, which are favorable for low-temperature denitrification activity. NH3-TPD experiments showed that compared to MoOx species, surface WOx species could provide more acidic sites, resulting in stronger surface acidity of the catalyst. Full article
(This article belongs to the Section Environmental Catalysis)
Show Figures

Graphical abstract

17 pages, 422 KiB  
Article
Impact of Co-Fed Hydrogen on High Conversion Propylene Aromatization on H-ZSM-5 and Ga/H-ZSM-5
by Christopher K. Russell, Josiah L. Rockey, Rebecca N. Hanna and Jeffrey T. Miller
Catalysts 2024, 14(7), 405; https://doi.org/10.3390/catal14070405 - 27 Jun 2024
Viewed by 123
Abstract
The expanded production of shale gas has increased the desire for developing methods for converting light alkanes, especially propane and ethane, into aromatic compounds (i.e., benzene, toluene, and xylene) for petrochemicals and fuels. The Cyclar process is one example of an industrial process [...] Read more.
The expanded production of shale gas has increased the desire for developing methods for converting light alkanes, especially propane and ethane, into aromatic compounds (i.e., benzene, toluene, and xylene) for petrochemicals and fuels. The Cyclar process is one example of an industrial process that has been demonstrated for the conversion of butane to aromatics; however, the conversion of lower molecular weight alkanes remains elusive. A multi-step process for the conversion of light alkanes to aromatics may be developed, where the first stage converts light alkanes into olefins and hydrogen, and the second stage converts olefins into aromatics. However, to determine the viability of this process, a better understanding of the performance of olefin aromatization in the presence of equimolar hydrogen is necessary. Herein, H-ZSM-5 and Ga-modified H-ZSM-5 are compared for propylene aromatization in the presence and absence of equimolar hydrogen at 1.9 kPa and 50 kPa partial pressures. The presence of H2 has no impact on the product distribution with H-ZSM-5 at either pressure. At 1.9 kPa with Ga/H-ZSM-5, similar product distributions are observed regardless of the presence or absence of H2 since Ga is not sufficiently active for hydrogenation to inhibit aromatics formation. However, at 50 kPa of H2 with Ga/H-ZSM-5, there is an increased selectivity to C4 products and a decrease in toluene and xylene selectivities at high conversions (i.e., χ > 80%), suggesting that aromatic dehydrogenation of cyclic hydrocarbons has been suppressed. Full article
(This article belongs to the Special Issue Research Advances in Zeolites and Zeolite-Based Catalysts)
12 pages, 676 KiB  
Article
Hydroprocessing of Gasoline on Modified Alumina Catalysts
by Balga Tuktin, Galymzhan Saidilda, Saule Nurzhanova and Yerdos Ongarbayev
Catalysts 2024, 14(7), 404; https://doi.org/10.3390/catal14070404 - 26 Jun 2024
Viewed by 209
Abstract
The hydroprocessing of gasoline on modified alumina catalysts makes it possible to obtain high-octane products. The implementation and development of the process have largely become possible due to the development of modified alumina catalysts that do not contain noble metals and exhibit special [...] Read more.
The hydroprocessing of gasoline on modified alumina catalysts makes it possible to obtain high-octane products. The implementation and development of the process have largely become possible due to the development of modified alumina catalysts that do not contain noble metals and exhibit special catalytic properties. This article discusses topical issues of petrochemistry, namely the creation of catalysts with improved characteristics for the production of high-octane gasoline with low sulfur content. New catalytic systems based on alumina and other carriers modified with transition metals, lanthanum and phosphorus were synthesized. Вy physico-chemical methods of analysis TPD of ammonia, TEM and XRD, we studied the acid–base and structural characteristics of the developed catalysts. The activity of the developed catalysts in the studied process of hydrotreating gasoline fractions depends on the structure and condition of the active centers. The process of hydrotreating straight-run gasoline in the presence of synthesized catalysts was carried out on a laboratory flow unit. It was shown that, during the hydrotreating of straight-run gasoline on the NiO-MoO3-La-P-HZSM-HY-Al2O3 catalyst, the octane number in the final product increased to 88.6, and the sulfur content decreased from 0.0088 to 0.001%. It was found that the minimum sulfur content in the gasoline hydrotreating product of 0.0005% was achieved on the catalyst CoO-WO3-La-P-HZSM-HY-Al2O3, which is significantly lower than for other studied catalytic systems. The obtained results of the sulfur content in the hydrotreating products fully comply with the Euro-5 standard. Thus, the efficiency of hydrotreating the gasoline fractions studied in this work was mainly determined by the nature of the carriers and modifiers used for the synthesis of catalysts and the technological parameters of the process. The synthesized catalysts showed high activity and selectivity, resulting in high-octane gasoline with a low sulfur content that meets international quality standards. Full article
(This article belongs to the Special Issue Catalysis for Bitumen/Heavy Oil Upgrading and Petroleum Refining)
16 pages, 4008 KiB  
Article
Enhanced Photodegradation of Acetaminophen Using Efficient ZnO-NiO Nanofibers
by Hassan E. Gomaa, Heba H. El-Maghrabi, Fatma A. Gomaa, Patrice Raynaud and Amr A. Nada
Catalysts 2024, 14(7), 403; https://doi.org/10.3390/catal14070403 - 26 Jun 2024
Viewed by 202
Abstract
The increasing presence of pharmaceutical pollutants, such as acetaminophen, in water bodies poses a significant environmental challenge due to their persistence and potential toxicity. This study investigated the enhanced photodegradation of acetaminophen using ZnO-NiO nanofibers as superior photocatalysts. The nanofibers synthesized with varying [...] Read more.
The increasing presence of pharmaceutical pollutants, such as acetaminophen, in water bodies poses a significant environmental challenge due to their persistence and potential toxicity. This study investigated the enhanced photodegradation of acetaminophen using ZnO-NiO nanofibers as superior photocatalysts. The nanofibers synthesized with varying NiO contents (designated as ZN0.5, ZN1, ZN1.5, and ZN2), were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), Raman, FTIR, Brunauer–Emmett–Teller (BET) analysis, and diffuse reflectance spectroscopy (DRS) to elucidate their structural, morphological, and optical properties. Thermogravimetric analysis (TGA) indicated that the nanofibers exhibit high thermal stability, with major weight loss attributed to the decomposition of the polymer matrix and residual organics. The BET analysis revealed that the specific surface area remains stable after increasing the NiO content up to a certain ratio. This stability correlates with the enhanced photocatalytic performance due to increased light absorption and improved charge separation. The diffuse reflectance spectra and Kubelka–Munk plots demonstrated a reduction in bandgap energy with higher NiO content, facilitating greater visible light absorption. Photocatalytic experiments under visible light irradiation, in the presence of peroxymonosulfate (PMS), showed that the ZN1.5 nanofibers achieved the highest acetaminophen degradation rate, i.e., 92%, within 3 h. Mechanistic studies, supported by radical trapping experiments, revealed that the improved photocatalytic efficiency is due to the synergistic effects of ZnO and NiO heterojunctions, which enhance charge separation and reactive oxygen species (ROS) generation. This research highlights the potential of ZnO-NiO nanofibers as effective photocatalysts for the degradation of pharmaceutical pollutants. The findings demonstrate that optimizing the composition and structure of nanofibers can significantly improve their environmental remediation capabilities, providing a promising solution for sustainable water treatment. Full article
(This article belongs to the Special Issue Advanced Catalytic Processes for Wastewater Treatment)
Show Figures

Figure 1

11 pages, 2493 KiB  
Article
A Bio-Based Tackifier Synthesized by Room-Temperature Cationic Copolymerization of Isobutene and β-Pinene
by Oluwaseyi Aderemi Ajala, Yuushou Nakayama, Takeshi Shiono and Ryo Tanaka
Catalysts 2024, 14(7), 402; https://doi.org/10.3390/catal14070402 - 26 Jun 2024
Viewed by 177
Abstract
Whereas the cationic homopolymerization of β-pinene and isobutene (IB) have been extensively studied, their copolymerization is still very scarce, and the conditions under which copolymerization can occur are limited to extremely low temperatures. Moreover, the application of the copolymer has not been reported. [...] Read more.
Whereas the cationic homopolymerization of β-pinene and isobutene (IB) have been extensively studied, their copolymerization is still very scarce, and the conditions under which copolymerization can occur are limited to extremely low temperatures. Moreover, the application of the copolymer has not been reported. Here, a series of room-temperature copolymerizations of β-pinene and IB, using group 13 compounds as catalysts, were conducted. The copolymerizations yielded a low molecular weight (Mn ~ 103) and a narrow molecular weight distribution (Mw/Mn < 2.0) copolymer, with a satisfactory yield at various comonomer feeds, and their glass transition temperature was predictable from the comonomer composition. Furthermore, the tackifying property of the obtained copolymer was investigated using a 180° peel adhesion test. A blend polymer of the copolymer and a styrene-isoprene triblock copolymer showed a high peeling force (0.58 ± 0.14 N/10 mm) and a glass transition temperature low enough for its application as a pressure-sensitive adhesive. Full article
(This article belongs to the Special Issue State-of-the-Art Polymerization Catalysis)
Show Figures

Graphical abstract

15 pages, 792 KiB  
Article
Palladium-Catalyzed Synthesis of 6-aryl Dopamine Derivatives
by Andrea Calcaterra, Santiago Fernández García, Federico Marrone, Roberta Bernini, Giancarlo Fabrizi, Antonella Goggiamani and Antonia Iazzetti
Catalysts 2024, 14(7), 401; https://doi.org/10.3390/catal14070401 - 25 Jun 2024
Viewed by 307
Abstract
Dopamine is a key neurotransmitter involved in a series of biologically relevant processes and its derivatives have sparked significant interest as intriguing synthetic targets. This class of compounds is indeed not only considerable for the potential biological activities but is also promising for [...] Read more.
Dopamine is a key neurotransmitter involved in a series of biologically relevant processes and its derivatives have sparked significant interest as intriguing synthetic targets. This class of compounds is indeed not only considerable for the potential biological activities but is also promising for diverse applications in material science. In light of this, our research was focused on the synthesis of 6-aryldopamine derivatives starting from 4-(2-aminoethyl)phenol through a sequential protocol, whose main steps are hydroxylation, halogenation, and Suzuki cross-coupling. Our method demonstrated versatility, efficiency, and compatibility with various functional groups, including aldehydes, ketones, esters, ethers, and fluorine. Full article
(This article belongs to the Section Catalytic Materials)
Show Figures

Graphical abstract

19 pages, 1284 KiB  
Article
Ni-Ag Catalysts for Hydrogen Production through Dry Reforming of Methane: Characterization and Performance Evaluation
by Hayat Henni, Rafik Benrabaa, Pascal Roussel and Axel Löfberg
Catalysts 2024, 14(7), 400; https://doi.org/10.3390/catal14070400 - 25 Jun 2024
Viewed by 359
Abstract
To investigate the influence of Ag and the loading of Ni species, Ni-Ag type catalysts were synthesized with varying Ni/Ag ratios (1, 1.5 and 2) using the coprecipitation method. The catalysts were extensively characterized using various techniques such as TG-DSC-SM, XRD, ICP, BET, [...] Read more.
To investigate the influence of Ag and the loading of Ni species, Ni-Ag type catalysts were synthesized with varying Ni/Ag ratios (1, 1.5 and 2) using the coprecipitation method. The catalysts were extensively characterized using various techniques such as TG-DSC-SM, XRD, ICP, BET, SEM-EDX and TPR and subsequently tested in the CH4/CO2 reaction without any pretreatment. Regardless of the ratio employed, a phase mixture containing NiO and Ag was observed after calcination under air between 600 °C and 1200 °C. SEM analysis confirmed the presence of a close interface between Ag and NiO. The specific surface area was found to be significantly higher for the catalyst with lower Ni content (R = 1). TPR analysis demonstrated that the inclusion of Ag facilitated the reduction of Ni at lower temperatures. XRD analyses of the spent catalyst confirmed catalyst reduction during the reaction. Among the samples, a catalyst with Ni/Ag = 1 exhibited superior catalytic activity without any pretreatment under a reduction atmosphere, in which case the conversions of methane and CO2 at 650 °C amounted to 38 and 45 mol%, respectively, with H2/CO = 0.7 and 71 mol% of H2. The presence of Ag species enhances the stability of the Ni catalyst and improves catalytic performance in the dry reforming of methane. Full article
17 pages, 5088 KiB  
Article
Structural Characterization of Enzymatic Interactions with Functional Nicotinamide Cofactor Biomimetics
by Raquel A. Rocha, Liam A. Wilson, Brett D. Schwartz, Andrew C. Warden, Luke W. Guddat, Robert E. Speight, Lara Malins, Gerhard Schenk and Colin Scott
Catalysts 2024, 14(7), 399; https://doi.org/10.3390/catal14070399 - 24 Jun 2024
Viewed by 370
Abstract
Synthetic nicotinamide biomimetics (NCBs) have emerged as alternatives to the use of natural cofactors. The relatively low cost and ease of manufacture of NCBs may enable the scaling of biocatalytic reactions to produce bulk chemicals (e.g., biofuels and plastics). NCBs are also recognized [...] Read more.
Synthetic nicotinamide biomimetics (NCBs) have emerged as alternatives to the use of natural cofactors. The relatively low cost and ease of manufacture of NCBs may enable the scaling of biocatalytic reactions to produce bulk chemicals (e.g., biofuels and plastics). NCBs are also recognized by only a subset of NAD(P)/NAD(P)H-dependent enzymes, which potentially allows access to orthogonal redox cascades that can be run simultaneously within a single reactor. In the work presented here, a series of NCBs was prepared and tested for activity with alcohol dehydrogenases and ene-reductases. While the NCBs did not support enzymatic activity with the alcohol dehydrogenases, the observed rate of the ene-reductases with NCBs was greater than when incubated with the natural cofactor (consistent with previous observations). We obtained the structures of an ene-reductase and an alcohol dehydrogenase with an NCB bound in their active sites. While the NCB bound to the ene-reductases in a productive position and orientation for hydride transfer to the isoalloxazine ring of the flavin cofactor, the NCB failed to adopt a catalytically competent binding mode in the alcohol dehydrogenase. Full article
(This article belongs to the Section Biocatalysis)
Show Figures

Figure 1

4 pages, 455 KiB  
Editorial
New Trends in Catalytic Reaction for High-Temperature and Low-Emission Combustion Technologies
by Baiqian Dai, Xiaojiang Wu and Lian Zhang
Catalysts 2024, 14(7), 398; https://doi.org/10.3390/catal14070398 - 24 Jun 2024
Viewed by 263
Abstract
With the continuous rise in global energy demand and the increasing awareness of environmental protection, high-temperature low-emission combustion technology has become a research hotspot in the field of combustion science [...] Full article
Show Figures

Figure 1

18 pages, 4680 KiB  
Article
In Situ Growth of Mn-Co3O4 on Mesoporous ZSM-5 Zeolite for Boosting Lean Methane Catalytic Oxidation
by Yuxuan Zhang, Ruibo Wei, Lin Yang, Jinming Ge, Feiyang Hu, Tingting Zhang, Fangyin Lu, Haiwang Wang and Jian Qi
Catalysts 2024, 14(7), 397; https://doi.org/10.3390/catal14070397 - 23 Jun 2024
Viewed by 333
Abstract
The low-temperature oxidation of methane gas in coal mine exhaust gas is important for reducing the greenhouse effect and protecting the environment. Unfortunately, the carbon–hydrogen bonds in methane molecules are highly stable, requiring higher reaction temperatures to achieve effective catalytic oxidation. However, metal [...] Read more.
The low-temperature oxidation of methane gas in coal mine exhaust gas is important for reducing the greenhouse effect and protecting the environment. Unfortunately, the carbon–hydrogen bonds in methane molecules are highly stable, requiring higher reaction temperatures to achieve effective catalytic oxidation. However, metal oxide-based catalysts face the problem of easy sintering and the deactivation of active components at high temperatures, which is an important challenge that catalysts need to overcome in practical applications. In this work, a series of Mn-Co3O4 active components were grown in situ on ZSM-5 zeolite with mesoporous pore structures treated with an alkaline solution via a hydrothermal synthesis method. Due to the presence of polyethylene glycol as a structure-directing agent, manganese can be uniformly doped into the Co3O4 lattice. The large specific surface area of ZSM-5 zeolite allows the active component Mn-Co3O4 to be uniformly dispersed, effectively preventing the sintering and growth of active component particles during the catalytic reaction process. It is worth mentioning that the Mn-Co3O4/meso-ZSM-5-6.67 catalyst has a methane conversion rate of up to 90% at a space velocity of 36,000 mL·g−1·h−1 and a reaction temperature of 363 °C. This is mainly due to the mesoporous ZSM-5 carrier with a high specific surface area, which is conducive to the adsorption and mass transfer of reaction molecules. The active component has an abundance of oxygen vacancies, which is conducive to the activation of reaction molecules and enhances its catalytic activity, which is even higher than that of noble metal-based catalysts. The new ideas for the preparation of metal oxide-based low-temperature methane oxidation catalysts proposed in this work are expected to provide new solutions for low-temperature methane oxidation reactions and promote technological progress in related fields. Full article
(This article belongs to the Special Issue Feature Papers in "Industrial Catalysis" Section)
7 pages, 408 KiB  
Editorial
Theme Issue in Memory to Professor Jiro Tsuji (1927–2022)
by Ewa Kowalska and Shuaizhi Zheng
Catalysts 2024, 14(7), 396; https://doi.org/10.3390/catal14070396 - 21 Jun 2024
Viewed by 334
Abstract
The importance of catalysis is obvious and unquestionable, especially bearing in mind that about 90% of all commercially produced chemical products involve catalysts at some step of their manufacture [...] Full article
(This article belongs to the Special Issue Theme Issue in Memory to Prof. Jiro Tsuji (1927–2022))
13 pages, 3630 KiB  
Article
Conservatively Perturbed Equilibrium (CPE)—Phenomenon as a Tool for Intensifying the Catalytic Process: The Case of Methane Reforming Processes
by Mykhailo O. Vilboi, Vitaliy R. Trishch and Gregory S. Yablonsky
Catalysts 2024, 14(7), 395; https://doi.org/10.3390/catal14070395 - 21 Jun 2024
Viewed by 246
Abstract
The phenomenon of conservatively perturbed equilibrium (CPE) was applied to the processes of methane reforming (dry and steam reforming) and analyzed using kinetic computer simulations. This phenomenon was studied for two products, CO and H2, at different temperatures. “Unperturbed” species with [...] Read more.
The phenomenon of conservatively perturbed equilibrium (CPE) was applied to the processes of methane reforming (dry and steam reforming) and analyzed using kinetic computer simulations. This phenomenon was studied for two products, CO and H2, at different temperatures. “Unperturbed” species with inlet concentrations equal to the outlet equilibrium concentration experienced unavoidable passing through the temporary extremum (the CPE point), in this case, the maximum. Application of the CPE phenomenon to the complex catalytic methane reforming processes demonstrate two improvements: 1. Achieving the over-equilibrium product concentration. 2. This concentration is achieved at the reactor length that is much shorter than the length corresponding to the vicinity of the complete equilibrium. Full article
(This article belongs to the Section Catalytic Reaction Engineering)
Show Figures

Figure 1

13 pages, 4379 KiB  
Article
Expediting Corrosion Engineering for Sulfur-Doped, Self-Supporting Ni-Fe Layered Dihydroxide in Efficient Aqueous Oxygen Evolution
by Yingjun Ma, Jie Wang, Hangning Liu, Lin Wang, Changhui Sun, Liangyu Gong, Xiaogang Zhang and Jiefang Zhu
Catalysts 2024, 14(7), 394; https://doi.org/10.3390/catal14070394 - 21 Jun 2024
Viewed by 264
Abstract
Electrochemical water-splitting is widely acknowledged as a renewable strategy for hydrogen production, but it is primarily constrained by the sluggish reaction kinetics of the anode oxygen evolution reaction (OER). In our study, we employ a fast room-temperature corrosion engineering strategy for the construction [...] Read more.
Electrochemical water-splitting is widely acknowledged as a renewable strategy for hydrogen production, but it is primarily constrained by the sluggish reaction kinetics of the anode oxygen evolution reaction (OER). In our study, we employ a fast room-temperature corrosion engineering strategy for the construction of a sulfur-doped Ni-Fe layered dihydroxide catalyst (S-NiFe LDH). With the assistance of a sulfur source, microsphere morphology with an ultra-thin lamellar surface cross-arrangement can be rapidly grown on the surface of an iron foam substrate, ensuring a substantial electrochemical interface. The composition of Ni species in the catalysts can be regulated by simply adjusting the amount of Ni2+ and reaction time. Functioning as an OER catalyst, the S-NiFe LDH demonstrates high activity and reaction kinetics, featuring a minimal overpotential of 120.0 mV to deliver a current density of 10 mA cm−2, a small Tafel slope of 39.5 mV dec−1 and a notable electrical double-layer capacitance (Cdl) of 31.3 mF cm−2. The remarkable electrocatalytic performance can be attributed to its distinctive three-dimensional (3D) structure and sulfur dopants, which effectively regulate the electrochemical interface and electronic structure of NiFe LDH. This work provides valuable insights for expeditious materials design. Full article
(This article belongs to the Special Issue Electrocatalysis for Hydrogen/Oxygen Evolution Reactions)
Show Figures

Figure 1

Previous Issue
Back to TopTop