Active Sites in Catalytic Reaction

A special issue of Catalysts (ISSN 2073-4344). This special issue belongs to the section "Environmental Catalysis".

Deadline for manuscript submissions: closed (31 August 2018) | Viewed by 72400

Special Issue Editor

Department of Chemical, Biomolecular, and Corrosion Engineering, University of Akron, Akron, OH 44320, USA
Interests: electrocatalysis and catalysis; chemical and electrochemical reaction engineering; sustainable and renewable energy; C1 chemical conversion; advanced materials synthesis and applications
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Special Issue Information

Dear Colleagues,

Catalysts, capable of promoting reaction kinetics and improving product selectivity, play an essential role in modern industrialized world. The past century has witnessed great successes in catalyst development, with many types of catalyst materials being developed and applied in different fields including economic chemical and petrochemical production, efficient energy generation, and environmental control. However most of these previous successes largely relied on trial-and-error experiments rather than theoretical guidance. This was because of experimental difficulty in identifying the active sites and determining the reaction pathways, both of which serve as important basis for rational catalyst search. With technological advances in characterization approaches and computational chemistry in recent years, identification of active sites and elucidation of catalysis mechanisms become possible and would lead to a new era in catalyst research. This Special Issue aims to cover recent progress and research efforts in identifying, creating and characterizing active sites in catalytic reaction and in elucidating and theoretically understanding catalysis on active sites. All experimental and theoretical works falling into the scope of this Special Issue, including original research papers, short communications, review articles, and perspective articles, are invited for submission.

Prof. Zhenmeng Peng
Guest Editor

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Keywords

  • Active site
  • Catalyst development
  • Reaction mechanism
  • Heterogeneous catalysis
  • Homogeneous catalysis
  • Enzyme catalysis
  • Electrocatalysis
  • Photoelectrocatalysis
  • Photocatalysis
  • Density functional theory

Published Papers (12 papers)

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Research

Jump to: Review

13 pages, 7182 KiB  
Article
Effect of Nickel Oxide Doping to Ceria-Supported Gold Catalyst for CO Oxidation and Water-Gas Shift Reactions
by Miao Shu, Shuai Wei, Chun-Jiang Jia, Dao-Lei Wang and Rui Si
Catalysts 2018, 8(12), 584; https://doi.org/10.3390/catal8120584 - 26 Nov 2018
Cited by 7 | Viewed by 3355
Abstract
Ceria-supported gold catalyst has drew much research interest owing to its high reactivity on CO oxidation and water-gas shift (WGS) reactions. However, till now, there were relatively limited studies on the effect of secondary metal/metal oxide component into gold-ceria system to enhance its [...] Read more.
Ceria-supported gold catalyst has drew much research interest owing to its high reactivity on CO oxidation and water-gas shift (WGS) reactions. However, till now, there were relatively limited studies on the effect of secondary metal/metal oxide component into gold-ceria system to enhance its catalytic performance. In this work, we synthetized the ceria supported gold-nickel samples via a deposition-precipitation method with the base of NaHCO3 to adjust final pH value of 8~9. We found that the addition of nickel oxide drove off the gold species from the stock solution during synthesis, and thus resulted in a dramatical decrease on doped Au concentration. No crystallized phases of gold and nickel were observed on the surface of ceria nanorods in both X-ray diffraction (XRD) and transmission electron microscopy (TEM). The valence of nickel was maintained as Ni2+ for all the measured samples by X-ray photoelectron spectroscopy (XPS), while gold was oxidized with the increased nickel amount after analysis of X-ray absorption near edge spectroscopy (XANES). The corresponding catalytic tests showed that with the introduction of nickel oxide, the activity of gold-ceria catalyst was promoted for the WGS reaction, but inhibited for the CO oxidation reaction. Full article
(This article belongs to the Special Issue Active Sites in Catalytic Reaction)
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12 pages, 3029 KiB  
Article
Two-Dimensional Mn-Co LDH/Graphene Composite towards High-Performance Water Splitting
by Jian Bao, Junfeng Xie, Fengcai Lei, Zhaolong Wang, Wenjun Liu, Li Xu, Meili Guan, Yan Zhao and Huaming Li
Catalysts 2018, 8(9), 350; https://doi.org/10.3390/catal8090350 - 28 Aug 2018
Cited by 27 | Viewed by 6065
Abstract
The oxygen evolution reaction (OER) is a complex multi-step four-electron process showing sluggish kinetics. Layered double hydroxides (LDH) were reported as promising catalysts for the OER, but their low electrical conductivity restricts their widespread applications. To overcome this problem, a composite material containing [...] Read more.
The oxygen evolution reaction (OER) is a complex multi-step four-electron process showing sluggish kinetics. Layered double hydroxides (LDH) were reported as promising catalysts for the OER, but their low electrical conductivity restricts their widespread applications. To overcome this problem, a composite material containing Mn-Co LDH ultrathin nanosheet and highly conductive graphene was synthesized for the first time. Benefited from the high electrocatalytic activity and the superior charge transfer ability induced by these components, the new material shows superior OER activity. Used as the OER catalyst, a high current density of 461 mA cm−2 at 2.0 V vs. RHE (reversible hydrogen electrode) was measured besides shows a low overpotential of 0.33 V at 10 mA cm−2. Moreover, the new composite also shows a superior bifunctional water splitting performance as catalyst for the OER and HER (hydrogen evolution reaction) catalysts. Our results indicate that the presented material is a promising candidate for water splitting which is cheap and efficient. Full article
(This article belongs to the Special Issue Active Sites in Catalytic Reaction)
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25 pages, 6062 KiB  
Article
Design of Specific Acid-Base-Properties in CeO2-ZrO2-Mixed Oxides via Templating and Au Modification
by Maja Glorius, Monica A. C. Markovits and Cornelia Breitkopf
Catalysts 2018, 8(9), 358; https://doi.org/10.3390/catal8090358 - 27 Aug 2018
Cited by 23 | Viewed by 4630
Abstract
Ceria-zirconia mixed oxides and gold supported oxides exhibit very good thermal stability and catalytic activity, as well as great selectivity. This work has been focused on the controlled synthesis and characterization of cationic- and amphiphilic-templated ceria, zirconia, and ceria-zirconia mixed oxides from nitrate [...] Read more.
Ceria-zirconia mixed oxides and gold supported oxides exhibit very good thermal stability and catalytic activity, as well as great selectivity. This work has been focused on the controlled synthesis and characterization of cationic- and amphiphilic-templated ceria, zirconia, and ceria-zirconia mixed oxides from nitrate and iso-propoxide precursors, and ceria-zirconia mixed oxides modified with gold via the deposition precipitation method with urea. The characterization of the acidic and basic properties was carried out through two test reactions. A complete chemical and structural characterization of the materials was done using Atomic Absorption Spectroscopy (AAS), Brunauer-Emmet-Teller Surface Analysis (N2-BET), X-Ray Diffraction (XRD), NH3- Temperature Programmed Desorption (TPD)/CO2-TPD, and Fourier Transform Infrared Spectroscopy (FTIR). Template techniques led to the formation of high surface area mesoporous materials with high activity and thermal stability. In general, the acid sites density was decreased, whereas the basic site density was increased by modification with Au or incorporation of zirconia in case of mixed oxides. Full article
(This article belongs to the Special Issue Active Sites in Catalytic Reaction)
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14 pages, 1943 KiB  
Article
Active Site of O2 and Its Improvement Mechanism over Ce-Ti Catalyst for NH3-SCR Reaction
by Dong Jiang, Shule Zhang, Yiqing Zeng, Pengfei Wang and Qin Zhong
Catalysts 2018, 8(8), 336; https://doi.org/10.3390/catal8080336 - 17 Aug 2018
Cited by 13 | Viewed by 3791
Abstract
The current study on Ce-Ti catalyst was mainly focused on the function of NH3 and NO adsorption sites. In our study, by comparing Ce-Ti (doped catalyst) to Ce/Ti (supported catalyst), the active site of O2 and its improvement mechanism over Ce-Ti [...] Read more.
The current study on Ce-Ti catalyst was mainly focused on the function of NH3 and NO adsorption sites. In our study, by comparing Ce-Ti (doped catalyst) to Ce/Ti (supported catalyst), the active site of O2 and its improvement mechanism over Ce-Ti catalyst for NH3-Selective catalytic reduction (SCR) reactions were investigated. For Ce-Ti catalyst, a cerium atom was confirmed entering a TiO2 crystal lattice by X-ray diffraction (XRD) and Raman; the structure of Ce-□-Ti (□ represents oxygen vacancy) in Ce-Ti catalyst was confirmed by X-ray photoelectron spectroscopy (XPS) and Photoluminescence spectra (PL spectra). The nature of this structure was characterized by electron paramagnetic resonance (EPR), Ammonia temperature-programmed desorption (NH3-TPD), hydrogen temperature-programmed reduction (H2-TPR), Nitric oxide temperature-programmed desorption (NO-TPD) and In situ DRIFT. The results indicated that oxygen vacancies had a promotive effect on the adsorption and activation of oxygen, and oxygen was converted to superoxide ions in large quantities. Also, because of adsorption and activation of NO and NH3, electrons were transferred to adsorbed oxygen via oxygen vacancies, which also promoted the formation of superoxide ions. We expected that our study could promote understanding of the active site of O2 and its improvement mechanism for doped catalyst. Full article
(This article belongs to the Special Issue Active Sites in Catalytic Reaction)
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11 pages, 4450 KiB  
Article
Clarification of Active Sites at Interfaces between Silica Support and Nickel Active Components for Carbon Monoxide Methanation
by Mengjuan Zhang, Panpan Li, Zhiqun Tian, Mingyuan Zhu, Fu Wang, Jiangbing Li, Bin Dai, Feng Yu, Hengshan Qiu and Hongwei Gao
Catalysts 2018, 8(7), 293; https://doi.org/10.3390/catal8070293 - 20 Jul 2018
Cited by 15 | Viewed by 4245
Abstract
Identification of active site is critical for developing advanced heterogeneous catalysis. Here, a nickel/silica (Ni/SiO2) catalyst was prepared through an ammonia-evaporation method for CO methanation. The as-obtained Ni/SiO2 catalyst shows a CO conversion of 96.74% and a methane selectivity of [...] Read more.
Identification of active site is critical for developing advanced heterogeneous catalysis. Here, a nickel/silica (Ni/SiO2) catalyst was prepared through an ammonia-evaporation method for CO methanation. The as-obtained Ni/SiO2 catalyst shows a CO conversion of 96.74% and a methane selectivity of 93.58% at 623 K with a weight hourly space velocity of 25,000 mL·g−1·h−1. After 150 h of continuous testing, the CO conversion still retains 96%, which indicates a high catalyst stability and long life. An in situ vacuum transmission infrared spectrum demonstrates that the main active sites locate at the interface between the metal Ni and the SiO2 at a wave number at 2060 cm−1 for the first time. The interesting discovery of the active site may offer a new insight for design and synthesis of methanation catalysts. Full article
(This article belongs to the Special Issue Active Sites in Catalytic Reaction)
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10 pages, 1911 KiB  
Article
Prickly Pear-Like Three-Dimensional Porous MoS2: Synthesis, Characterization and Advanced Hydrogen Evolution Reaction
by Huiting Lu, Xin Chen, Wenhao Dai, Kai Zhang, Conghui Liu and Haifeng Dong
Catalysts 2018, 8(6), 235; https://doi.org/10.3390/catal8060235 - 04 Jun 2018
Cited by 3 | Viewed by 4335
Abstract
Herein, we hydrothermally synthesize a type of prickly pear-like three-dimensional (3D) porous MoS2 (ZT-MoS2), using a zinc oxide (ZnO) rod deposited on quartz glass substrates, as a template for an advanced hydrogen evolution reaction (HER) catalyst. Microscopic and spectroscopic tools [...] Read more.
Herein, we hydrothermally synthesize a type of prickly pear-like three-dimensional (3D) porous MoS2 (ZT-MoS2), using a zinc oxide (ZnO) rod deposited on quartz glass substrates, as a template for an advanced hydrogen evolution reaction (HER) catalyst. Microscopic and spectroscopic tools comprehensively characterize the morphology of the ZT-MoS2 nanostructure, which exhibits adequate edge active sites and defects, as well as a high component of active octahedral MoS2 (1T-MoS2). Electrochemical characterizations reveal the good HER performance of the ZT-MoS2 that presents a good overpotential of 110 mV, and a Tafel slope of 63 mV·dec−1, superior to most of the previously reported MoS2-based HER catalysts. This work contributes to the design and fabrication of 3D MoS2 with enhanced HER performance, which holds great promise for fuel cells and energy conversion. Full article
(This article belongs to the Special Issue Active Sites in Catalytic Reaction)
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10 pages, 4361 KiB  
Article
Nitrogen-Doped Porous Carbon Derived from Bamboo Shoot as Solid Base Catalyst for Knoevenagel Condensation and Transesterification Reactions
by Bingbing Mi, Xiufang Chen, Changle Jiang, Jingxin Wang, Xiujuan Chen, Bo Zhang, Xianmiao Liu, Zhijia Liu and Benhua Fei
Catalysts 2018, 8(6), 232; https://doi.org/10.3390/catal8060232 - 04 Jun 2018
Cited by 9 | Viewed by 3505
Abstract
Highly porous nitrogen-doped carbons derived from bamboo shoots (BSNCs) were prepared through an in-situ synthesis method. The results showed that BSNCs had a large specific surface area, a relatively high nitrogen content and hierarchically porous structures. The catalytic properties of BSNCs were evaluated [...] Read more.
Highly porous nitrogen-doped carbons derived from bamboo shoots (BSNCs) were prepared through an in-situ synthesis method. The results showed that BSNCs had a large specific surface area, a relatively high nitrogen content and hierarchically porous structures. The catalytic properties of BSNCs were evaluated based on Knoevenagel condensation and transesterification reactions. Deprotonated BSNC-700 exhibited high efficiency for the model reactions as a solid base catalyst, and the superior sample deprotonated in tBuOK solution with a concentration of 0.1 increased the conversion rate from 16.1% to 76.0% for Knoevenagel condensation. The two reactions proceeded smoothly in the presence of deprotonated BSNC-700. The results also showed that the catalyst could be recycled for several times for Knoevenagel condensation. The results from this research will provide a guideline to develop bamboo shoot as a precursor to fabricate a superb solid base catalyst. Full article
(This article belongs to the Special Issue Active Sites in Catalytic Reaction)
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13 pages, 2366 KiB  
Article
Single-Atom Mn Active Site in a Triol-Stabilized β-Anderson Manganohexamolybdate for Enhanced Catalytic Activity towards Adipic Acid Production
by Jianhui Luo, Yichao Huang, Bin Ding, Pingmei Wang, Xiangfei Geng, Jiangwei Zhang and Yongge Wei
Catalysts 2018, 8(3), 121; https://doi.org/10.3390/catal8030121 - 19 Mar 2018
Cited by 26 | Viewed by 5616
Abstract
Adipic acid is an important raw chemical for the commercial production of polyamides and polyesters. The traditional industrial adipic acid production utilizes nitric acid to oxidize KA oil (mixtures of cyclohexanone and cyclohexanol), leading to the emission of N2O and thus [...] Read more.
Adipic acid is an important raw chemical for the commercial production of polyamides and polyesters. The traditional industrial adipic acid production utilizes nitric acid to oxidize KA oil (mixtures of cyclohexanone and cyclohexanol), leading to the emission of N2O and thus causing ozone depletion, global warming, and acid rain. Herein, we reported an organically functionalized β-isomer of Anderson polyoxometalates (POMs) nanocluster with single-atom Mn, β-{[H3NC(CH2O)3]2MnMo6O18} (1), as a highly active catalyst to selectively catalyze the oxidation of cyclohexanone, cyclohexanol, or KA oil with atom economy use of 30% H2O2 for the eco-friendly synthesis of adipic acid. The catalyst has been characterized by single crystal and powder XRD, XPS, ESI-MS, FT-IR, and NMR. A cyclohexanone (cyclohexanol) conversion of >99.9% with an adipic acid selectivity of ~97.1% (~85.3%) could be achieved over catalyst 1 with high turnover frequency of 2427.5 h−1 (2132.5 h−1). It has been demonstrated that the existence of Mn3+ atom active site in catalyst 1 and the special butterfly-shaped topology of POMs both play vital roles in the enhancement of catalytic activity. Full article
(This article belongs to the Special Issue Active Sites in Catalytic Reaction)
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12 pages, 2406 KiB  
Article
The H2-Treated TiO2 Supported Pt Catalysts Prepared by Strong Electrostatic Adsorption for Liquid-Phase Selective Hydrogenation
by Sasithorn Kuhaudomlap, Okorn Mekasuwandumrong, Piyasan Praserthdam, Shin-Ichiro Fujita, Masahiko Arai and Joongjai Panpranot
Catalysts 2018, 8(2), 87; https://doi.org/10.3390/catal8020087 - 22 Feb 2018
Cited by 11 | Viewed by 4994
Abstract
The H2-treated TiO2 supported Pt catalysts were prepared by strong electrostatic adsorption method and tested in the liquid-phase selective hydrogenation of various organic compounds such as 3-nitrostyrene to vinylaniline (VA) and furfural to furfuryl alcohol (FA). A combination of high [...] Read more.
The H2-treated TiO2 supported Pt catalysts were prepared by strong electrostatic adsorption method and tested in the liquid-phase selective hydrogenation of various organic compounds such as 3-nitrostyrene to vinylaniline (VA) and furfural to furfuryl alcohol (FA). A combination of high Pt dispersion, strong interaction of Pt-TiOx, and the presence of low coordination Pt sites was necessary for high hydrogenation activity. However, while the selectivity of VA in 3-nitrostyrene hydrogenation did not depend much on the catalyst preparation method used, the selectivity of FA in furfural hydrogenation was much higher when the catalysts were prepared by SEA, comparing to those obtained by impregnation in which the solvent product was formed, due probably to the non-acidic conditions used during Pt loading by SEA method. Full article
(This article belongs to the Special Issue Active Sites in Catalytic Reaction)
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Review

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20 pages, 2965 KiB  
Review
Active Sites in Heterogeneous Catalytic Reaction on Metal and Metal Oxide: Theory and Practice
by Yanbo Pan, Xiaochen Shen, Libo Yao, Abdulaziz Bentalib and Zhenmeng Peng
Catalysts 2018, 8(10), 478; https://doi.org/10.3390/catal8100478 - 20 Oct 2018
Cited by 60 | Viewed by 16854
Abstract
Active sites play an essential role in heterogeneous catalysis and largely determine the reaction properties. Yet identification and study of the active sites remain challenging owing to their dynamic behaviors during catalysis process and issues with current characterization techniques. This article provides a [...] Read more.
Active sites play an essential role in heterogeneous catalysis and largely determine the reaction properties. Yet identification and study of the active sites remain challenging owing to their dynamic behaviors during catalysis process and issues with current characterization techniques. This article provides a short review of research progresses in active sites of metal and metal oxide catalysts, which covers the past achievements, current research status, and perspectives in this research field. In particular, the concepts and theories of active sites are introduced. Major experimental and computational approaches that are used in active site study are summarized, with their applications and limitations being discussed. An outlook of future research direction in both experimental and computational catalysis research is provided. Full article
(This article belongs to the Special Issue Active Sites in Catalytic Reaction)
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18 pages, 3220 KiB  
Review
First-Principles Modeling in Heterogeneous Electrocatalysis
by Dominic R. Alfonso, De Nyago Tafen and Douglas R. Kauffmann
Catalysts 2018, 8(10), 424; https://doi.org/10.3390/catal8100424 - 28 Sep 2018
Cited by 26 | Viewed by 6034
Abstract
The last decade has witnessed tremendous progress in the development of computer simulation based on quantum mechanical description of the interactions between electrons and between electrons and atomic nuclei with electrode potentials taken into account–promoting the possibility to model electrocatalytic reactions. The cornerstone [...] Read more.
The last decade has witnessed tremendous progress in the development of computer simulation based on quantum mechanical description of the interactions between electrons and between electrons and atomic nuclei with electrode potentials taken into account–promoting the possibility to model electrocatalytic reactions. The cornerstone of this development was laid by the widely used computational hydrogen electrode method which involves a posteriori correction of standard constant charge first principles studies in solvent environment. The description of this technique and its contribution to our effort to understand electrocatalytic reactions on the active sites of metal-based nanoparticles are reviewed. The pathways and energetics of the relevant elementary reactions are presented. We also discussed a recent attempt in the literature to account for the inflow and outflow of electrons from the electrode as electrochemical reactions proceed, which has been greatly assisted by the development of density functional theory within the grand canonical framework. Going beyond the computational hydrogen electrode method by explicit incorporation of electrode potential within the calculations permits access to more detailed insights without requiring extra computational burden. Full article
(This article belongs to the Special Issue Active Sites in Catalytic Reaction)
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35 pages, 30917 KiB  
Review
Covalent Organic Frameworks: Promising Materials as Heterogeneous Catalysts for C-C Bond Formations
by Dongge Ma, Yi Wang, Anan Liu, Shuhong Li, Chichong Lu and Chuncheng Chen
Catalysts 2018, 8(9), 404; https://doi.org/10.3390/catal8090404 - 19 Sep 2018
Cited by 37 | Viewed by 8086
Abstract
Covalent organic frameworks (COFs) are defined as highly porous and crystalline polymers, constructed and connected via covalent bonds, extending in two- or three-dimension. Compared with other porous materials such as zeolite and active carbon, the versatile and alternative constituent elements, chemical bonding types [...] Read more.
Covalent organic frameworks (COFs) are defined as highly porous and crystalline polymers, constructed and connected via covalent bonds, extending in two- or three-dimension. Compared with other porous materials such as zeolite and active carbon, the versatile and alternative constituent elements, chemical bonding types and characteristics of ordered skeleton and pore, enable the rising large family of COFs more available to diverse applications including gas separation and storage, optoelectronics, proton conduction, energy storage and in particular, catalysis. As the representative candidate of next-generation catalysis materials, because of their large surface area, accessible and size-tunable open nano-pores, COFs materials are suitable for incorporating external useful active ingredients such as ligands, complexes, even metal nanoparticles deposition and substrate diffusion. These advantages make it capable to catalyze a variety of useful organic reactions such as important C-C bond formations. By appropriate pore-engineering in COFs materials, even enantioselective asymmetric C-C bond formations could be realized with excellent yield and ee value in much shorter reaction time compared with their monomer and oligomer analogues. This review will mainly introduce and discuss the paragon examples of COFs materials for application in C-C bond formation reactions for the organic synthetic purpose. Full article
(This article belongs to the Special Issue Active Sites in Catalytic Reaction)
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