Clever fusion of structure and function: A coupled sulfurization-driven OER performance study based on ZIF-67 nanoparticles and NiMoO4 nanorods

Hydrogen fuel cells (HFCs) and water electrolysis are emerging clean energy technologies that can alleviate the problems of environmental pollution and energy shortage. Oxygen Extraction Reaction (OER) is a slow four-electron transfer process with a high energy barrier, and often regarded as the bottleneck of a series of clean energy technologies. In this paper, NiMoO4 nanorods (denoted as NMO) were in situ grown on nickel foam substrate, and then ZIF-67 nanoparticles were assembled onto NiMoO4 nanorods (denoted as NMO@ZIF-67). Finally, the surface layers of NiMoO4 nanorods and ZIF-67 nanoparticles were vulcanized by hydrothermal treatment for 6 h to obtain the catalyst NiMoO4@NiMoCo-S-6 (denoted as NMO@NMC-S-6). In 1 M KOH aqueous solution, NMO@NMC-S-6 exhibited excellent electrochemical performance, only 176 mV and 243 mV overpotentials were required at current densities of 10 and 100 mA cm-2, respectively, and Tafel slope of NMO@NMC-S-6 is 24.81 mV dec-1. In addition, benefitting from the combined structure of nanorods and nanoparticles effectively prevented nanoparticles aggregation and enhanced its own structure and transport channel stability, NMO@NMC-S-6 showed remarkable stability in 20 h electrochemical test. This work brings a reference orientation for constructing cost-efficient alkaline OER catalyst through structure combination strategy.