Analyzing the Case for Bifunctional Catalysis

Andersen, Mie; Medford, Andrew J.; Nørskov, Jens K.; Reuter, Karsten

doi:10.1002/anie.201601049

Cited by 72 publications

(83 citation statements)

References 22 publications

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“…For one of the most important reasons, DFT calculations have provided the insight into predicting the ORR/OER activity of the materials. [3,[10][11][12][13][14][15][16] This physical framework is used to estimate the free energy changes corresponding to elementary steps involving proton-coupled electron transfer on the catalyst surface. For the other, some analytical and characterization techniques including Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, X-ray absorption/diffraction, Mössbauer spectroscopy and so on, allow us to monitor the ORR/OER in situ and confirm the actual active phase/intermediates and electrochemical behavior during ORR/OER on the surface of the materials.…”

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confidence: 99%

Design of Efficient Bifunctional Oxygen Reduction/Evolution Electrocatalyst: Recent Advances and Perspectives

Huang

Wang

Peng

et al. 2017

Advanced Energy Materials

709

448

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Oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) are the two most important reactions in rechargeable metal‐air battery, a promising technology to meet the energy requirements for various applications. The development of low‐cost, highly efficient and stable bifunctional ORR/OER catalysts is critical for a large‐scale application of this technology. In this review, the authors first introduce the fundamentals of bifunctional ORR/OER electrocatalysis in alkaline electrolyte. Various types of nanostructured materials as bifunctional ORR/OER catalysts including metal oxide, hydroxide and sulfide, functional carbon material, metal, and their composites are then reviewed. The crucial factors that can be used to tune the activity of the catalyst towards ORR/OER are summarized, including (1) phase, morphology, crystal facet, defect, mixed‐metal and strain engineering for metal oxide; (2) heteroatom doping, topological defects, and formation of metal‐N‐C structure for carbon material; (3) alloy effect for metal. These experiences lay the foundation for large scale application of metal‐air battery and can also effectively guide the rational design of catalysts for other electrocatalytic reactions.

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mentioning

confidence: 99%

Design of Efficient Bifunctional Oxygen Reduction/Evolution Electrocatalyst: Recent Advances and Perspectives

Huang

Wang

Peng

et al. 2017

Advanced Energy Materials

709

448

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“…Thefact that edges respond strongly to diffusion and presence of facet sites,isrelated to the supply of oxygen. [30,31] These results further emphasize the benefit of having awide distribution of sites to benefit from the principle of least resistance. Forthe present reaction, alarge difference in reactivity between low and high-coordinated sites leads to ab eneficial situation where CO and Oc an be abundant on the particle simultaneously.T his enhances the activity as compared to reactions over extended surfaces, where the reaction energy landscape is homogeneous.…”

Section: Angewandte Chemiementioning

confidence: 67%

The Site‐Assembly Determines Catalytic Activity of Nanoparticles

Jørgensen

Grönbeck

2018

Angewandte Chemie

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Heterogeneous catalysts are often designed as metal nanoparticles supported on oxide surfaces.H ere,t he relation between particle morphology and reaction kinetics is investigated by scaling relation kinetic Monte Carlo simulations using CO oxidation over Pt nanoparticles as amodel reaction. We find that different particle morphologies result in vastly different catalytic activities.The activity is strongly affected by kinetic couplings between sites,a nd aw ide site distribution generally enhances the activity.The present study highlights the role of site-assemblies as aconcept that, in addition to isolated active sites,c an be used to understand catalytic reactions over nanoparticles.Heterogeneous catalysts are commonly realized as metal nanoparticles supported on oxide-surfaces.The nanoparticles in technical catalysts are generally ill-defined with respect to shape and size,a nd the contribution of different particle geometries and sizes to the measured catalytic activity is difficult to disentangle.T he situation can be further complicated by changes in particle shape arising in response to the reaction conditions. [1-3] As particle shape may affect catalytic activity,itbecomes important to understand the link between particle morphology and catalyst performance.T his topic, although central, has not received much systematic attention. Experimental studies of multiple reactions have revealed size and shape dependencies of the activity. [4][5][6][7] Theoretically, density functional theory [8,9] (DFT) calculations have outlined how adsorption properties depend on particle geometry, [10,11] which has been rationalized by descriptors such as coordination numbers and d-band centers. [12][13][14][15] Structure sensitivity in the catalytic activity has generally been investigated by dividing the catalyst into isolated facets with one type of site. [13,16] However,t reating sites as isolated entities implies that kinetic couplings between the sites are neglected. CO oxidation is ap rototypical model reaction, for which microkinetic models have predicted reactivity and size dependence for different metal particles. [17,18] However,these models were formulated in the mean field approximation (MFA), which does not account for the specific arrangement and detailed kinetic couplings of sites.T he importance of as ite distribution, or site-assembly,h ave previously been recognized as complex kinetic couplings,b oth experimentally [19] and by schematic kinetic Monte Carlo simulations. [20] These studies indicate that the site-assembly can be crucial for the reaction kinetics,h owever without quantitative estimates.T hus there is agap in the understanding of the relation between particle morphology and catalytic activity.Thepresent article explores the relation between particle geometry and catalytic activity,b yp resenting first-principles kinetic Monte Carlo simulations over nanoparticles of different shapes,u sing CO oxidation over Pt nanoparticles as an archetype reaction. We find that identical sites on different geome...

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“…Although scaling relationships predict Au to have good selectivity (albeit poor activity) for alcohol synthesis, decreasing size of nanoparticles can shift the activity to favor CO oxidation . At present, the insights gained from scaling relationships for alcohol synthesis are primarily limited to metals, but the combination of active metals and oxides such as metal‐exchanged zeolites and mixed metal oxides can be used to break away from the activity/selectivity limits observed in these relationships . Separate reaction steps can be optimized on different active sites for an overall better reaction performance.…”

Section: Resultsmentioning

confidence: 99%

Thermodynamic Limitations of the Catalyst Design Space for Methanol Production from Methane

2018

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Current efforts to overcome the challenges of direct methane to methanol processes have focused on designing heterogeneous catalysts that perform methane partial oxidation using cheap and abundant oxidants such as molecular oxygen and water. An evaluation of the thermodynamic limitations of methanol production with the use of these oxidants is required to understand the maximum possible conversion and selectivity for a given feed composition and temperature. When O2 is present, the formation of the most thermodynamically stable product, carbon dioxide, must be inhibited. At practical temperatures for moderate scale processes, water as the sole oxidant results in extremely low steady‐state methane conversion, but higher yields can be achieved with coupled surface reactions. This work evaluates these thermodynamic challenges and opportunities for catalysts that can selectively oxidize methane to methanol with oxygen and water and discusses routes for achieving high methanol yields.

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Analyzing the Case for Bifunctional Catalysis

Cited by 72 publications

References 22 publications

Design of Efficient Bifunctional Oxygen Reduction/Evolution Electrocatalyst: Recent Advances and Perspectives

Design of Efficient Bifunctional Oxygen Reduction/Evolution Electrocatalyst: Recent Advances and Perspectives

The Site‐Assembly Determines Catalytic Activity of Nanoparticles

Thermodynamic Limitations of the Catalyst Design Space for Methanol Production from Methane

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