Mechanism insights and design strategies for metal-organic framework-based alkaline hydrogen evolution reaction electrocatalysts

Abstract

Currently, hydrogen, as a renewable energy carrier, plays a pivotal role in the sustainable development of future energy. Hydrogen evolution reaction (HER) can effectively convert water into green hydrogen, which is also an ideal model reaction in electrocatalytic fields for comprehending reaction mechanism and exploring high-efficient catalysts. Nevertheless, HER kinetics under alkaline conditions is 2–3 orders of magnitude lower than that under acidic conditions and the fundamental reason for the kinetic pH effect is still ambiguous. Therefore, designing effective alkaline HER catalysts and exploring its reaction mechanism are essential for reversible hydrogen recycle. Particularly, metal-organic framework (MOF) materials are highly porous structures formed by the coordination of metal center and organic ligand. In view of the advantages of large specific surface area, adjustable pore size, and tunable and various compositions, MOF-based materials have been widely explored as the alkaline HER electrocatalysts. Herein, we reviewed recent development of MOF-based catalysts towards alkaline HER, with emphases on reaction mechanism and design strategies. Firstly, this review analyzed the HER mechanism from the perspective of distinct reactive intermediates. Then, the recent research on MOF-based alkaline HER catalysts have been summarized from doping, alloying and constructing heterostructure strategies, focusing on the inherent correlation between the adsorption/desorption behaviors of efficient reaction intermediates and the electrocatalytic performance. In the end, challenges and prospects for the development of MOF-based alkaline HER electrocatalysts are discussed.