Single-atom catalysis for zinc-air/O2 batteries, water electrolyzers and fuel cells applications

We summarize the latest progress achieved in precious and non-precious carbon based single-atom catalytic active sites, including Pd, Pt, Ir, Ru, Rh, Au, Fe, Co, Mn, Zn, Sn, and Cu, aiming at facilitating metal-air/O2 batteries, water electrolyzers, and fuel-cells commercialization. Correspondingly, several aspects of the intrinsic catalytic activity, for example, the role of center-metal-atoms, number and type of metal-coordinated atoms, and the surrounding environment of central-metal-atom, are systematically discussed. This review includes two major parts: i) the rational summary of recently reported catalysts, comprising synthesis/identification approaches of active-sites to catalytic performance, and ii) the basic key factors, influencing the performance. Equal emphasis is given to experimental results and theoretical calculations to figure out the structure-function correlation between the active-sites configuration and the intrinsic electrocatalytic performance. A research paradigm is suggested to design advanced single-metal-atom catalysts for fuel cells and metal-air batteries. Regardless of these developments, we highlight some remaining debatable issues that require urgent attention. Finally, we provide a comprehensive perspective on the development and progress of single-metal-atom catalysts for fuel cells and batteries. © 2021 Elsevier B.V