MOF-derived Co/Co3O4/C hollow structural composite as an efficient electrocatalyst for hydrogen evolution reaction

Stable, efficient catalysts are crucial for electrochemical water splitting. Metal-organic frameworks (MOFs) can be used to create electrocatalysts meeting these criteria; however, the lack of high-quality electrode materials for the hydrogen evolution reaction impedes their adoption. In this study, a hollow-structured Co/Co3O4/C composite was prepared using a Co-based MOF precursor through a two-step pyrolysis-oxidation process. This composite outperformed nonhollow Co/Co3O4/C structures as well as hollow Co/C and Co3O4/C composites as a catalyst for hydrogen production in alkaline media. It had a low overvoltage of 169 mV at a current density of 10 mA cm(-2) and a moderate Tafel slope of 60.7 mV dec-(1). Moreover, it exhibited remarkable durability with 2000 cycles and 12 h of testing. This can be attributed to the synergistic effect of Co, Co3O4, and the hollow morphological architecture, which promote the dissociation of HO-H bonds, recombination of hydrogen intermediates, and efficient electron transfer. The results of this study are highly promising for the fabrication of cost-effective electrode materials for water splitting.