Molecular design and coordination regulation of atomically dispersed bi-functional catalysts for oxygen electrocatalysis

The oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) play important roles in new sustainable energy conversion devices to address the dilemma of energy shortage, but are limited by slow electrochemical kinetic processes. Atomically dispersed catalysts (ADCs) with maximized utilization and well-defined configurations point the way to design efficient and cost-effective multifunctional electrocatalysts. In this paper, we illustrate the relationship between the structure and multifunctional performance of mono-disperse catalysts using reversible oxygen electrocatalysis as an example. Significantly, carbon materials and metal compounds are described as equally important substrate materials. For carbon-based mono-disperse catalysts, the realization of atomic metal sites on carbon supports and the regulation of intrinsic activity are reviewed from the following aspects: molecular design (including substrate design and selection of a center metal atom) and coordination environment. Besides, the substrates of non-carbon-based mono-disperse catalysts are divided into metal oxides, sulfides and carbides/nitrides, and the catalytic mechanism and regulation methods are described. Finally, the prospects and challenges of mono-disperse catalysts for multifunctional electrocatalytic reactions are discussed.