Bifunctional Single Atom Catalysts for Rechargeable Zinc–Air Batteries: From Dynamic Mechanism to Rational Design

Abstract

Ever‐growing demands for rechargeable zinc–air batteries (ZABs) call for efficient bifunctional electrocatalysts. Among various electrocatalysts, single atom catalysts (SACs) have received increasing attention due to the merits of high atom utilization, structural tunability, and remarkable activity. Rational design of bifunctional SACs relies heavily on an in‐depth understanding of reaction mechanisms, especially dynamic evolution under electrochemical conditions. This requires a systematic study in dynamic mechanisms to replace current trial and error modes. Herein, fundamental understanding of dynamic oxygen reduction reaction and oxygen evolution reaction mechanisms for SACs is first presented combining in situ and/or operando characterizations and theoretical calculations. By highlighting structure–performance relationships, rational regulation strategies are particularly proposed to facilitate the design of efficient bifunctional SACs. Furthermore, future perspectives and challenges are discussed. This review provides a thorough understanding of dynamic mechanisms and regulation strategies for bifunctional SACs, which are expected to pave the avenue for exploring optimum single atom bifunctional oxygen catalysts and effective ZABs.

Mechanosynthesis of a bifunctional FeNi–N–C oxygen electrocatalyst via facile mixed-phase templating and preheating-pyrolysis

“…5 In particular, metal–air batteries (MABs) are gaining attention as promising options for storing renewable energy efficiently and at a low cost. 6,7 MABs show remarkable theoretical energy density, which can be 5 to 25 times higher than that of current analogs. 8 MABs, however, are hindered by the kinetics of the two main reactions, the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER).…”

Local structural environment of single-atom catalysts

“…15 Therefore, downsizing the catalyst particles or clusters to single-atoms is extremely desirable for catalytic reactions because atomically isolated sites often function as active sites. [14][15][16][17][18][19][20][21] Single metal atoms are ubiquitous in natural biological enzymes as active centers; 22 e.g. the active centers of chlorophyll, heme and nitrogenase are Mg, Fe and Mo atoms, respectively.…”

“…15 Therefore, downsizing the catalyst particles or clusters to single-atoms is extremely desirable for catalytic reactions because atomically isolated sites often function as active sites. 14–21…”

Transition Metal Functionalized C30N12S6 as High-Performance Trifunctional Catalysts with Integrated Descriptors toward Hydrogen Evolution, Oxygen Evolution, and Oxygen Reduction Reactions: A Case of High-Throughput First-Principles Screening within the Framework of TM–N2@C30N10S6

“…The ever-increasing consumption for fossil fuels, as well as environmental crises caused by extravagant usage, have compelled scientists to reconsider the green and renewable energy storage and conversion technologies such as overall water-splitting, fuel cells, and metal–air batteries source of energy. − For these technologies, the crucial building blocks, consisting of the hydrogen evolution reaction (HER), oxygen evolution reaction (OER), and oxygen reduction reaction (ORR), depend sensitively on catalysts to achieve target catalytic performance. − As yet, the widely recognized best-performing electrocatalysts are still advanced noble metal-based compounds such as Pt/C for HER, Ru/Ir-based oxides for OER, and Pt-based material for ORR. − However, the large-scale usage of these widely used commercial electrocatalysts toward industrial sectors is severely limited by their high cost and limited reserves. To make these reactions achieve efficient catalysis, efficient and low-cost materials are highly desirable for expediting the corresponding electrochemical processes.…”