The concept of active site in heterogeneous catalysis

Nature Reviews Chemistry, Journal Year: 2022, Volume and Issue: 6(2), P. 89 - 111

Published: Jan. 6, 2022

Language: Английский

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Potential-Driven Restructuring of Cu Single Atoms to Nanoparticles for Boosting the Electrochemical Reduction of Nitrate to Ammonia

Journal of the American Chemical Society, Journal Year: 2022, Volume and Issue: 144(27), P. 12062 - 12071

Published: June 29, 2022

Restructuring is ubiquitous in thermocatalysis and of pivotal importance to identify the real active site, yet it less explored electrocatalysis. Herein, by using operando X-ray absorption spectroscopy conjunction with advanced electron microscopy, we reveal restructuring as-synthesized Cu-N4 single-atom site nanoparticles ∼5 nm during electrochemical reduction nitrate ammonia, a green ammonia production route upon combined plasma-assisted oxidation nitrogen. The Cu2+ Cu+ Cu0 subsequent aggregation single atoms found occur concurrently enhancement NH3 rate, both them are driven applied potential switching from 0.00 -1.00 V versus RHE. maximum rate reaches 4.5 mg cm-2 h-1 (12.5 molNH3 gCu-1 h-1) Faradaic efficiency 84.7% at RHE, outperforming most other Cu catalysts reported previously. After electrolysis, aggregated reversibly disintegrated into then restored structure being exposed an ambient atmosphere, which masks potential-induced reaction. synchronous changes percentage suggests that genuine sites for corroborated post-deposited NP catalyst density functional theory calculations.

Language: Английский

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Lattice oxygen redox chemistry in solid-state electrocatalysts for water oxidation

Energy & Environmental Science, Journal Year: 2021, Volume and Issue: 14(9), P. 4647 - 4671

Published: Jan. 1, 2021

Lattice oxygen redox chemistry in solid-state electrocatalysts rationalizes the remarkable OER activity by lattice oxygen-mediated mechanism. Here we elucidate fundamental principle of this mechanism and summarize recently related developments.

Language: Английский

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Electrochemical CO2 reduction (CO2RR) to multi-carbon products over copper-based catalysts

Coordination Chemistry Reviews, Journal Year: 2021, Volume and Issue: 454, P. 214340 - 214340

Published: Dec. 13, 2021

Language: Английский

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Electrocatalysis in Alkaline Media and Alkaline Membrane-Based Energy Technologies

Chemical Reviews, Journal Year: 2022, Volume and Issue: 122(6), P. 6117 - 6321

Published: Feb. 8, 2022

Hydrogen energy-based electrochemical energy conversion technologies offer the promise of enabling a transition global landscape from fossil fuels to renewable energy. Here, we present comprehensive review fundamentals electrocatalysis in alkaline media and applications alkaline-based technologies, particularly fuel cells water electrolyzers. Anion exchange (alkaline) membrane (AEMFCs) enable use nonprecious electrocatalysts for sluggish oxygen reduction reaction (ORR), relative proton (PEMFCs), which require Pt-based electrocatalysts. However, hydrogen oxidation (HOR) kinetics is significantly slower than acidic media. Understanding these phenomena requires applying theoretical experimental methods unravel molecular-level thermodynamics and, particularly, proton-coupled electron transfer (PCET) process that takes place proton-deficient Extensive spectroscopic studies, on single-crystal Pt metal oxides, have contributed development activity descriptors, as well identification nature active sites, rate-determining steps HOR ORR. Among these, structure reactivity interfacial serve key potential pH-dependent kinetic factors are helping elucidate origins ORR differences acids bases. Additionally, deliberately modulating controlling catalyst–support interactions provided valuable insights enhancing catalyst accessibility durability during operation. The design synthesis highly conductive durable membranes/ionomers enabled AEMFCs reach initial performance metrics equal or higher those PEMFCs. We emphasize importance using electrode assemblies (MEAs) integrate often separately pursued/optimized electrocatalyst/support membranes/ionomer components. Operando/in situ methods, at multiscales, ab initio simulations provide mechanistic understanding electron, ion, mass transport catalyst/ionomer/membrane interfaces necessary guidance achieve cell operation air over thousands hours. hope this Review will roadmap advancing scientific fundamental governing with ultimate goal achieving ultralow precious-metal-free high-performance related technologies.

Language: Английский

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Oxygen Evolution/Reduction Reaction Catalysts: From In Situ Monitoring and Reaction Mechanisms to Rational Design

Chemical Reviews, Journal Year: 2023, Volume and Issue: 123(9), P. 6257 - 6358

Published: March 21, 2023

The oxygen evolution reaction (OER) and reduction (ORR) are core steps of various energy conversion storage systems. However, their sluggish kinetics, i.e., the demanding multielectron transfer processes, still render OER/ORR catalysts less efficient for practical applications. Moreover, complexity catalyst–electrolyte interface makes a comprehensive understanding intrinsic mechanisms challenging. Fortunately, recent advances in situ/operando characterization techniques have facilitated kinetic monitoring under conditions. Here we provide selected highlights mechanistic studies with main emphasis placed on heterogeneous systems (primarily discussing first-row transition metals which operate basic conditions), followed by brief outlook molecular catalysts. Key sections this review focused determination true active species, identification sites, reactive intermediates. For in-depth insights into above factors, short overview metrics accurate characterizations is provided. A combination obtained time-resolved information reliable activity data will then guide rational design new Strategies such as optimizing restructuring process well overcoming adsorption-energy scaling relations be discussed. Finally, pending current challenges prospects toward development homogeneous presented.

Language: Английский

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Perfecting electrocatalystsviaimperfections: towards the large-scale deployment of water electrolysis technology

Energy & Environmental Science, Journal Year: 2021, Volume and Issue: 14(4), P. 1722 - 1770

Published: Jan. 1, 2021

A tuned electronic structure favors the electrocatalytic water splitting reactionviaaccelerating reaction kinetics, changing rate-determining step, and optimizing adsorption energy for intermediates; this is achievedviaintentionally incorporating imperfections into crystal lattices of electrocatalysts.

Language: Английский

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Steering the structure and selectivity of CO2 electroreduction catalysts by potential pulses

Nature Catalysis, Journal Year: 2022, Volume and Issue: 5(4), P. 259 - 267

Published: April 21, 2022

Abstract Convoluted selectivity trends and a missing link between reaction product distribution catalyst properties hinder practical applications of the electrochemical CO 2 reduction (CO RR) for multicarbon generation. Here we employ operando X-ray absorption diffraction methods with subsecond time resolution to unveil surprising complexity catalysts exposed dynamic conditions. We show that by using pulsed protocol consisting alternating working oxidizing potential periods dynamically perturb derived from Cu O nanocubes, one can decouple effect ensemble coexisting copper species on distribution. In particular, an optimized balance oxidized reduced surface achieved within narrow range cathodic anodic pulse durations resulted in twofold increase ethanol production compared static RR This work thus prepares ground steering through controlled structural chemical transformations.

Language: Английский

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Emerging low-nuclearity supported metal catalysts with atomic level precision for efficient heterogeneous catalysis

Nano Research, Journal Year: 2022, Volume and Issue: 15(9), P. 7806 - 7839

Published: June 2, 2022

Language: Английский

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Insight into Structural Evolution, Active Sites, and Stability of Heterogeneous Electrocatalysts

Angewandte Chemie International Edition, Journal Year: 2021, Volume and Issue: 61(11)

Published: Sept. 7, 2021

Studying structure-activity correlations of electrocatalysts is essential for improving the conversion electrical to chemical energy. Recently, increasing evidence obtained by operando characterization techniques reveal that structural evolution catalysts caused interplay with electric fields, electrolytes and reactants/intermediates brings about formation real active sites. Hence, it time summarize related research advances envisage future developments. In this Minireview, we first introduce fundamental concepts associated (e.g., catalysts, sites/centers stability/lifetime) their relevance. Then, multiple triggers advanced characterizations are discussed. Significantly, a brief overview its reversibility in heterogeneous electrocatalysis provided, especially representative electrocatalytic oxygen reaction (OER) CO2 reduction (CO2 RR) processes. Lastly, key challenges opportunities exciting field highlighted.

Language: Английский

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