A Study on the Electrochemical Performance of MOF Based HER Catalysts for Anion Exchange Membrane Water Electrolysis

Recently, research on anion exchange membrane water electrolysis (AEMWE) has been conducted, which has the advantage of using a non-noble transition metal catalyst to reduce cost and improve the activity and durability of the catalyst. In alkaline solutions, heterojunction catalysts are favored because the rational design of catalysts requires the ability to simultaneously dissociate water and bind hydrogen species. In this study, N-doped carbon hollow polyhedron (NCHP) supports were synthesized using two types of metal-organic frameworks (MOFs) to enhance catalyst durability by effective active site-support interactions. Moreover, well dispersed MoC on MOFs with regularly connected metal nodes and organic ligands increased the number of active sites and improved the reaction kinetics owing to the synergistic effects between MoC and Co@NC, which enhanced the hydrogen evolution reaction (HER). The formation mechanism of NCHP was confirmed by transmission electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. During the half-cell test, the incorporation of MoC (MoC-Co@NC/NCHP) reduced the HER overpotential by approximately 1.8 times at 10mA/cm 2 compared with that of Co@NC/NCHP. Furthermore, durability cycling was conducted from 0.1 to -0.6 V versus a reversible hydrogen electrode (RHE). The durability tests revealed that after 3000 cycles, the reduction in the HER current of MoC-Co@NC/NCHP was 1.4 and 2.7 times lower than those of Co@NC/NCHP and commercial Pt/C, respectively. This study provides two strategies to obtain highly stable NC matrix supports and highly active heterojunction catalysts.