Optimizing Atomically Dispersed Metal Electrocatalysts for Hydrogen Evolution: Chemical Coordination Effect and Electronic Metal Support Interaction

Hydrogen has emerged as a green and sustainable fuel to meet the demand for future global energy. Distinct from steam reforming, electrochemical water splitting, especially powered by renewables, has been considered as a promising technique for scalable production of high-purity hydrogen with no carbon emission. Its commercialization depends on accelerating reaction kinetics and thus reduction of hydrogen cost, requiring electrocatalysts that are efficient, economical, and capable of stable and sustained hydrogen production. Atomically dispersed metal carbon-based catalysts (ADMCs) have attracted extensive attention due to their high atom utilization, abundant accessible active sites, fast mass transfer, and well-defined and tunable structures as ideal models for commercialized hydrogen production catalysts. However, boosting the performances of ADMCs for HER still requires new-captions of rational structural design. In this review, starting from the recently developed strategies of ADMCs synthesis, the microenvironment regulation of active sites of ADMCs are systematically summarized and discussed, such as atomically metal doping, synergetic atomically doping and ADMCs supported nanocrystals. With attention on the catalytic mechanisms and structure-activity relationships ranging from chemical coordination effects and electronic metal-support interaction, the active origin of ADMCs in the electrocatalytic hydrogen evolution reaction is discussed. Finally, the review outlooks the remaining challenges and emerging research topics in the future, including long service life, amplification preparation techniques, high-output alkaline water electrolysis, seawater electrolysis for hydrogen production and large current density hydrogen evolution. The new insights and knowledge into these aspects will be helpful for filling the existing gaps between scientific communities and industries and open up opportunities for bringing this promising technology into reality.