In-situ generate robust Fe–Ni derived nano-catalyst featuring surface reconstruction for enhanced oxygen evolution reaction

Oxygen evolution reaction (OER) catalysts with highly efficient and cost-effective are cardinal for hydrogen production through water electrolysis. Herein, a novel strategy based on the theory of molecular crystallization and atomic diffusion is described to construct the FeOOH@Ni3(NO3)2(OH)4/NF. It requires an overpotential of 248 mV at the current density of 100 mA cm−2 for OER. The in-situ Raman spectroscopy test exploring the catalytic actives unravels that NiOOH is one of the real active species and a small amount of NiFe2O4 is generated during OER process. The analysis of the mechanism shows that NiOOH converted from the intermediate product of Ni(OH)2 derived from Ni3(NO3)2(OH)4 in the process of OER. NiOOH and FeOOH mainly work together contributing to boosting intrinsic catalytic activity. This work may provide a new insight into fabricating strategy for other nano-catalysts. The in-situ Raman measurement provides a valid and reliable means to probe into the catalytic active site and catalytic mechanism in the catalytic process.