Perspectives on the Active Sites and Catalyst Design for the Hydrogenation of Dimethyl Oxalate

ACS Catalysis ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 4465-4490 ◽  
Author(s):  
Run-Ping Ye ◽  
Ling Lin ◽  
Lu-Cun Wang ◽  
Dong Ding ◽  
Zhangfeng Zhou ◽  
...  
Keyword(s):  
Active Sites ◽  
Catalyst Design ◽  
Dimethyl Oxalate

Towards a Design of Active Oxygen Evolution Catalysts: Insights from Automated Density Functional Theory Calculations and Machine Learning

2019 ◽  
Author(s):  
Seoin Back ◽  
Kevin Tran ◽  
Zachary Ulissi
Keyword(s):  
Machine Learning ◽  
Oxygen Evolution ◽  
Active Sites ◽  
Density Functional ◽  
Chemical Space ◽  
Density Functional Theory Calculations ◽  
Catalyst Design ◽  
Transition Metal Catalysts ◽  
Oxide Materials ◽  
Design Strategies

<div> <div> <div> <div><p>Developing active and stable oxygen evolution catalysts is a key to enabling various future energy technologies and the state-of-the-art catalyst is Ir-containing oxide materials. Understanding oxygen chemistry on oxide materials is significantly more complicated than studying transition metal catalysts for two reasons: the most stable surface coverage under reaction conditions is extremely important but difficult to understand without many detailed calculations, and there are many possible active sites and configurations on O* or OH* covered surfaces. We have developed an automated and high-throughput approach to solve this problem and predict OER overpotentials for arbitrary oxide surfaces. We demonstrate this for a number of previously-unstudied IrO2 and IrO3 polymorphs and their facets. We discovered that low index surfaces of IrO2 other than rutile (110) are more active than the most stable rutile (110), and we identified promising active sites of IrO2 and IrO3 that outperform rutile (110) by 0.2 V in theoretical overpotential. Based on findings from DFT calculations, we pro- vide catalyst design strategies to improve catalytic activity of Ir based catalysts and demonstrate a machine learning model capable of predicting surface coverages and site activity. This work highlights the importance of investigating unexplored chemical space to design promising catalysts.<br></p></div></div></div></div><div><div><div> </div> </div> </div>

Toward rational catalyst design for partial hydrogenation of dimethyl oxalate to methyl glycolate: a descriptor-based microkinetic analysis

2019 ◽  
Vol 9 (20) ◽  
pp. 5763-5773 ◽  
Author(s):  
Wei-Qi Yan ◽  
Jun-Bo Zhang ◽  
Ling Xiao ◽  
Yi-An Zhu ◽  
Yue-Qiang Cao ◽  
...  
Keyword(s):  
Catalyst Design ◽  
Partial Hydrogenation ◽  
Dimethyl Oxalate ◽  
Catalyst Screening ◽  
Methyl Glycolate ◽  
Rational Catalyst Design

A descriptor-based microkinetic analysis has been performed to provide a basis for the catalyst screening for DMO hydrogenation to MG.

scholarly journals Influence of the Greater Protein Environment on the Electrostatic Potential in Metalloenzyme Active Sites: the Case of Formate Dehydrogenase

2021 ◽  
Author(s):  
Azadeh Nazemi ◽  
Adam Steeves ◽  
Heather Kulik
Keyword(s):  
Electrostatic Potential ◽  
Active Site ◽  
Active Sites ◽  
Formate Dehydrogenase ◽  
Catalyst Design ◽  
Metal Center ◽  
Ambient Conditions ◽  
Shift Analysis ◽  
The Impact ◽  
Protein Environment

The Mo/W containing metalloenzyme formate dehydrogenase (FDH) is an efficient and selective natural catalyst which reversibly converts CO2 to formate under ambient conditions. A greater understanding of the role of the protein environment in determining the local properties of the FDH active site would enable rational bioinspired catalyst design. In this study, we investigate the impact of the greater protein environment on the electrostatic potential (ESP) of the active site. To model the enzyme environment, we used a combination of long-timescale classical molecular dynamics (MD) and multiscale quantum-mechanical/molecular-mechanical (QM/MM) simulations. We leverage the charge shift analysis method to systematically construct QM regions and analyze the electronic environment of the active site by evaluating the degree of charge transfer between the core active site and the protein environment. The contribution of the terminal chalcogen ligand to the ESP of the metal center is substantial and dependent on the chalcogen identity, with ESPs less negative and similar for Se and S terminal chalcogens than for O regardless of whether the Mo6+ or W6+ metal center is present. Our evaluation reveals that the orientation of the sidechains and ligand conformations will alter the relative trends in the ESP observed for a given metal center or terminal chalcogen, highlighting the importance of sampling dynamic fluctuations in the protein. Overall, our observations suggest that the terminal chalcogen ligand identity plays an important role in the enzymatic activity of FDH.

scholarly journals Monolithic substrate support catalyst design considerations for steam methane reforming operation

2018 ◽  
Vol 34 (4) ◽  
pp. 481-501 ◽  
Author(s):  
Luqmanulhakim Baharudin ◽  
Matthew James Watson
Keyword(s):  
Active Sites ◽  
Catalyst Deactivation ◽  
Practical Aspect ◽  
Catalyst Design ◽  
Severe Reaction ◽  
Conductive Heat ◽  
Reaction Conditions ◽  
Design Considerations ◽  
Steam Methane ◽  
Substrate Support

Abstract This paper reviews the research undertaken to study the design criteria that address the monolithic support structure requirements in steam reforming operation for the effective mass transfer of process gases to the active sites and effective conductive heat transfer through tube wall to the active catalytic areas, as well as low pressure drop operation. Design considerations include selection of substrate materials that possess good mechanical strength to withstand the severe reaction conditions and prevent catalyst crushing that would lead to carbon formation and catalyst deactivation, and excessive heating of the tube that results in hot spots which is fatal to tube lifetime. The support’s mechanical properties are listed for the purpose of providing guidelines on verifying the structure durability. The practical aspect of packaging and stacking the monolith structures in the reformer tube for ease of loading and discharge is discussed to understand its readiness in industrial application.

scholarly journals Recent Progress in Atomic-Level Understanding of Cu/SSZ-13 Selective Catalytic Reduction Catalysts

Catalysts ◽  
2018 ◽  
Vol 8 (4) ◽  
pp. 140 ◽  
Author(s):  
◽  
Keyword(s):  
Selective Catalytic Reduction ◽  
Active Sites ◽  
Catalytic Reduction ◽  
Short Review ◽  
Catalytic Performance ◽  
Catalyst Design ◽  
Catalyst Stability ◽  
Hydrothermal Aging ◽  
Scr Catalysts ◽  
Fast Scr

Cu/SSZ-13 Selective Catalytic Reduction (SCR) catalysts have been extensively studied for the past five-plus years. New and exciting fundamental and applied science has appeared in the literature quite frequently over this time. In this short review, a few topics specifically focused on a molecular-level understanding of this catalyst are summarized: (1) The nature of the active sites and, in particular, their transformations under varying reaction conditions that include dehydration, the presence of the various SCR reactants and hydrothermal aging; (2) Discussions of standard and fast SCR reaction mechanisms. Considerable progress has been made, especially in the last couple of years, on standard SCR mechanisms. In contrast, mechanisms for fast SCR are much less understood. Possible reaction paths are hypothesized for this latter case to stimulate further investigations; (3) Discussions of rational catalyst design based on new knowledge obtained regarding catalyst stability, overall catalytic performance and mechanistic catalytic chemistry.

scholarly journals Ceria-Based Catalysts Studied by Near Ambient Pressure X-ray Photoelectron Spectroscopy: A Review

Catalysts ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 286 ◽  
Author(s):  
Xènia Garcia ◽  
Lluís Soler ◽  
Núria J. Divins ◽  
Xavier Vendrell ◽  
Isabel Serrano ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Active Sites ◽  
Ambient Pressure ◽  
High Vacuum ◽  
Modern Science ◽  
Catalyst Design ◽  
Oxygen Storage ◽  
Solid Catalyst ◽  
Essential Information ◽  
X Ray

The development of better catalysts is a passionate topic at the forefront of modern science, where operando techniques are necessary to identify the nature of the active sites. The surface of a solid catalyst is dynamic and dependent on the reaction environment and, therefore, the catalytic active sites may only be formed under specific reaction conditions and may not be stable either in air or under high vacuum conditions. The identification of the active sites and the understanding of their behaviour are essential information towards a rational catalyst design. One of the most powerful operando techniques for the study of active sites is near ambient pressure X-ray photoelectron spectroscopy (NAP-XPS), which is particularly sensitive to the surface and sub-surface of solids. Here we review the use of NAP-XPS for the study of ceria-based catalysts, widely used in a large number of industrial processes due to their excellent oxygen storage capacity and well-established redox properties.

scholarly journals Highly efficient nonprecious metal catalyst prepared with metal–organic framework in a continuous carbon nanofibrous network

2015 ◽  
Vol 112 (34) ◽  
pp. 10629-10634 ◽  
Author(s):  
Jianglan Shui ◽  
Chen Chen ◽  
Lauren Grabstanowicz ◽  
Dan Zhao ◽  
Di-Jia Liu
Keyword(s):  
Fuel Cell ◽  
Active Sites ◽  
Large Scale ◽  
Catalyst Design ◽  
High Price ◽  
Metal Catalyst ◽  
Membrane Electrode ◽  
Zeolitic Imidazolate Framework ◽  
Highly Efficient ◽  
Nonprecious Metal

Fuel cell vehicles, the only all-electric technology with a demonstrated >300 miles per fill travel range, use Pt as the electrode catalyst. The high price of Pt creates a major cost barrier for large-scale implementation of polymer electrolyte membrane fuel cells. Nonprecious metal catalysts (NPMCs) represent attractive low-cost alternatives. However, a significantly lower turnover frequency at the individual catalytic site renders the traditional carbon-supported NPMCs inadequate in reaching the desired performance afforded by Pt. Unconventional catalyst design aiming at maximizing the active site density at much improved mass and charge transports is essential for the next-generation NPMC. We report here a method of preparing highly efficient, nanofibrous NPMC for cathodic oxygen reduction reaction by electrospinning a polymer solution containing ferrous organometallics and zeolitic imidazolate framework followed by thermal activation. The catalyst offers a carbon nanonetwork architecture made of microporous nanofibers decorated by uniformly distributed high-density active sites. In a single-cell test, the membrane electrode containing such a catalyst delivered unprecedented volumetric activities of 3.3 A⋅cm−3 at 0.9 V or 450 A⋅cm−3 extrapolated at 0.8 V, representing the highest reported value in the literature. Improved fuel cell durability was also observed.

Towards a Design of Active Oxygen Evolution Catalysts: Insights from Automated Density Functional Theory Calculations and Machine Learning

2019 ◽  
Author(s):  
Seoin Back ◽  
Kevin Tran ◽  
Zachary Ulissi
Keyword(s):  
Machine Learning ◽  
Oxygen Evolution ◽  
Active Sites ◽  
Density Functional ◽  
Chemical Space ◽  
Density Functional Theory Calculations ◽  
Catalyst Design ◽  
Transition Metal Catalysts ◽  
Oxide Materials ◽  
Design Strategies

<div> <div> <div> <div><p>Developing active and stable oxygen evolution catalysts is a key to enabling various future energy technologies and the state-of-the-art catalyst is Ir-containing oxide materials. Understanding oxygen chemistry on oxide materials is significantly more complicated than studying transition metal catalysts for two reasons: the most stable surface coverage under reaction conditions is extremely important but difficult to understand without many detailed calculations, and there are many possible active sites and configurations on O* or OH* covered surfaces. We have developed an automated and high-throughput approach to solve this problem and predict OER overpotentials for arbitrary oxide surfaces. We demonstrate this for a number of previously-unstudied IrO2 and IrO3 polymorphs and their facets. We discovered that low index surfaces of IrO2 other than rutile (110) are more active than the most stable rutile (110), and we identified promising active sites of IrO2 and IrO3 that outperform rutile (110) by 0.2 V in theoretical overpotential. Based on findings from DFT calculations, we pro- vide catalyst design strategies to improve catalytic activity of Ir based catalysts and demonstrate a machine learning model capable of predicting surface coverages and site activity. This work highlights the importance of investigating unexplored chemical space to design promising catalysts.<br></p></div></div></div></div><div><div><div> </div> </div> </div>

scholarly journals Recent Advances in the Catalyst Design and Mass Transport Control for the Electrochemical Reduction of Carbon Dioxide to Formate

Catalysts ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 859 ◽  
Author(s):  
Muhammad Alfath ◽  
Chan Woo Lee
Keyword(s):  
Mass Transport ◽  
Electrochemical Reduction ◽  
Active Sites ◽  
Co2 Reduction ◽  
Aqueous Solubility ◽  
Reduction Reaction ◽  
Catalyst Design ◽  
Catalyst Composition ◽  
Reduction Of Co2 ◽  
Formate Production

Closing the carbon cycle by the electrochemical reduction of CO2 to formic acid and other high-value chemicals is a promising strategy to mitigate rapid climate change. The main barriers to commercializing a CO2 reduction reaction (CO2RR) system for formate production are the chemical inertness, low aqueous solubility, and slow mass transport characteristics of CO2, along with the low selectivity and high overpotential observed in formate production via CO2 reduction. To address those problems, we first explain the possible reaction mechanisms of CO2RRs to formate, and then we present and discuss several strategies to overcome the barriers to commercialization. The electronic structure of the catalyst can be tuned to favor a specific intermediate by adjusting the catalyst composition and tailoring the facets, edges, and corners of the catalyst to better expose the active sites, which has primarily led to increased catalytic activity and selectivity. Controlling the local pH, employing a high-pressure reactor, and using systems with three-phase boundaries can tune the mass transport properties of reactants at the catalyst surface. The reported electrocatalytic performances are summarized afterward to provide insight into which strategies have critical effects on the production of formate.

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