Yan Yang, Jiaju Fu, Yun Zhang, Ali A. Ensafi, and Jin-Song Hu

J. Phys. Chem. C 2021, 125, 41, 22397–22420. https://pubs.acs.org/doi/abs/10.1021/acs.jpcc.1c07682

ABSTRACT: In the face of the environmental and energy crisis, the commercialization of advanced electrochemical energy conversion technology based on basic reactions like the hydrogen evolution reaction (HER), the oxygen reduction reaction (ORR), the oxygen evolution reaction (OER), and the CO2 reduction reaction (CO2RR) calls for the development of low-cost and highefficiency non-precious-metal (NPM) electrocatalysts. The ideal NPM electrocatalysts usually feature (1) highly active intrinsic sites; (2) high-density and uniform active sites to reduce the energy barrier of the reaction and increase the surface electronmass transfer rate, thus improving the activity, turnover efficiency, and selectivity of the catalyst. Molecular engineering strategy is an effective approach to realize the bottom-up construction of highperformance NPM electrocatalysts with well-defined active sites. In this review, the recent progress about utilizing molecules including small molecules, metal−organic frameworks (MOF), covalent organic frameworks (COF), biomolecules, and polyoxometalate (POM) as precursors to build NPM electrocatalysts (M−NC single-atom catalysts, NPM-based materials, and metal-free carbon-based materials) with high-loading-density and well-defined active sites for electrochemical energy conversion are summarized. Finally, the prospects and challenges for the future development of high-performance and industrially applicable electrocatalysts are proposed.