Performance enhancement and degradation mechanism identification of a single-atom Co–N–C catalyst for proton exchange membrane fuel cells

Nature Catalysis, Год журнала: 2020, Номер 3(12), С. 1044 - 1054

Опубликована: Ноя. 30, 2020

Язык: Английский

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Coexisting Single‐Atomic Fe and Ni Sites on Hierarchically Ordered Porous Carbon as a Highly Efficient ORR Electrocatalyst

Advanced Materials, Год журнала: 2020, Номер 32(42)

Опубликована: Сен. 16, 2020

The development of oxygen reduction reaction (ORR) electrocatalysts based on earth-abundant nonprecious materials is critically important for sustainable large-scale applications fuel cells and metal-air batteries. Herein, a hetero-single-atom (h-SA) ORR electrocatalyst presented, which has atomically dispersed Fe Ni coanchored to microsized nitrogen-doped graphitic carbon support with unique trimodal-porous structure configured by highly ordered macropores interconnected through mesopores. Extended X-ray absorption fine spectra confirm that Fe- Ni-SAs are affixed the via FeN4 NiN4 coordination bonds. resultant Fe/Ni h-SA exhibits an outstanding activity, outperforming SA only or Ni-SAs, benchmark Pt/C. obtained experimental results indicate achieved performance from synergetic enhancement induced coexisting sites, superior mass-transfer capability promoted trimodal-porous-structured support.

Язык: Английский

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Atomically dispersed iron sites with a nitrogen–carbon coating as highly active and durable oxygen reduction catalysts for fuel cells

Nature Energy, Год журнала: 2022, Номер 7(7), С. 652 - 663

Опубликована: Июль 7, 2022

Язык: Английский

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High loading of single atomic iron sites in Fe–NC oxygen reduction catalysts for proton exchange membrane fuel cells

Nature Catalysis, Год журнала: 2022, Номер 5(4), С. 311 - 323

Опубликована: Апрель 25, 2022

Язык: Английский

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Atomically Dispersed Fe–Co Dual Metal Sites as Bifunctional Oxygen Electrocatalysts for Rechargeable and Flexible Zn–Air Batteries

ACS Catalysis, Год журнала: 2022, Номер 12(2), С. 1216 - 1227

Опубликована: Янв. 5, 2022

Single-metal site catalysts have exhibited highly efficient electrocatalytic properties due to their unique coordination environments and adjustable local structures for reactant adsorption electron transfer. They been widely studied many electrochemical reactions, including oxygen reduction reaction (ORR) evolution (OER). However, it remains a significant challenge realize high-efficiency bifunctional catalysis (ORR/OER) with single-metal-type active sites. Herein, we report atomically dispersed Fe–Co dual metal sites (FeCo–NC) derived from Fe Co co-doped zeolitic imidazolate frameworks (ZIF-8s), aiming build up multiple ORR/OER catalysts. The FeCo–NC catalyst shows excellent catalytic activity in alkaline media the ORR (E1/2 = 0.877 V) OER (Ej=10 1.579 V). Moreover, its outstanding stability during is comparable noble-metal (Pt/C RuO2). atomic dispersion state, structure, charge density difference of were characterized determined using advanced physical characterization functional theory (DFT) calculations. FeCo–N6 moieties are likely main simultaneously improved performance relative traditional single We further incorporated into an air electrode fabricating rechargeable flexible Zn–air batteries, generating superior power (372 mW cm–2) long-cycle (over 190 h) stability. This work would provide method design synthesize multi-metal electrocatalysis.

Язык: Английский

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Electrocatalysis in Alkaline Media and Alkaline Membrane-Based Energy Technologies

Chemical Reviews, Год журнала: 2022, Номер 122(6), С. 6117 - 6321

Опубликована: Фев. 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.

Язык: Английский

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Oxygen Reduction Electrocatalysts toward Practical Fuel Cells: Progress and Perspectives

Angewandte Chemie International Edition, Год журнала: 2021, Номер 60(33), С. 17832 - 17852

Опубликована: Фев. 5, 2021

Fuel cells are an incredibly powerful renewable energy technology, but their broad applications remains lagging because of the high cost and poor reliability cathodic electrocatalysts for oxygen reduction reaction (ORR). This review focuses on recent progress ORR in fuel cells. More importantly, it highlights fundamental problems associated with insufficient activity translation from rotating disk electrode to membrane assembly Finally, atomic-level in-depth information catalysts cells, potential perspectives suggested, including large-scale preparation, unified assessment criteria, advanced interpretation techniques, simulation artificial intelligence. aims provide valuable insights into science technical engineering efficient

Язык: Английский

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

Chemical Reviews, Год журнала: 2023, Номер 123(9), С. 6257 - 6358

Опубликована: Март 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.

Язык: Английский

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Recent Advances in MOF‐Derived Single Atom Catalysts for Electrochemical Applications

Advanced Energy Materials, Год журнала: 2020, Номер 10(38)

Опубликована: Авг. 13, 2020

Abstract Electrocatalysis plays a critical role in clean energy conversion, enabling great improvement for future sustainable technologies. Single atom catalysts (SACs) derived from metal–organic framework (MOF) are emerging extraordinary materials electrochemical catalytic applications. Covering the merits of unique electronic structure, low‐coordination environment, quantum size effect, and metal–support interaction, SACs promise enhanced electrocatalytic activity, stability, selectivity field conversion. In this article, MOF synthesis routes to afford well‐dispersed along with respective mechanism systematically reviewed first, typical examples each strategy carefully discussed. Then characterization techniques understanding isolated spatial distribution, local coordination environment SACs, insights into stable mechanisms provided by density functional theory (DFT) calculations summarized. addition, several important applications MOF‐derived including oxygen reduction reaction, CO 2 nitrogen hydrogen evolution etc., highlighted. To facilitate development high‐performing technical challenges corresponding research directions proposed.

Язык: Английский

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Electrocatalysis of Single-Atom Sites: Impacts of Atomic Coordination

ACS Catalysis, Год журнала: 2020, Номер 10(14), С. 7584 - 7618

Опубликована: Июнь 11, 2020

Single metal atoms embedded within select supporting matrices have shown great potential in the development of high-efficiency, low-cost electrocatalysts because maximal atom utilization and mass activity. As single are stabilized by coordination bonds with substrate, strong metal–support interactions can be exploited for ready manipulation electrocatalytic activity selectivity toward target reactions. However, most single-atom catalysts (SACs) prepared pyrolysis contain a wide range structures. Resolving atomic configurations moieties represents critical first step establishment an unambiguous correlation between SAC structure In this Review, we summarize recent progress studies electrocatalysts, focus on impacts sites activities series reactions that important various electrochemical energy technologies, such as hydrogen evolution reaction, oxygen reduction nitrogen CO2 so on. The survey entails SACs, from noble metals (e.g., Pt, Pd, Ru, Ir, Au, etc.) to non-noble Fe, Co, Ni, Cu, etc.), supported variety substrate materials pristine doped carbon, metal, oxide, sulfide, etc.). Finally, Review concludes perspective highlighting promises challenges further SACs context chemistry.

Язык: Английский

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