In situ Raman Monitoring of Surface Structures and Oxygen Species on Ni(OH)₂/Au/Nickel Foam During Oxygen Evolution Reaction

Nickel foam is a prevalent material for the oxygen evolution reaction (OER) in alkaline media. Herein, we employed a one-step electrodeposition technique to effectively fabricate a Ni(OH)2/Au/nickel foam (denoted as a Ni(OH)2/Au/NF) catalyst. This catalyst exhibits both surface-enhanced Raman scattering (SERS) activity and catalytic activity. The electrochemical SERS technique is employed for in situ monitoring of surface structure changes and intermediates during the OER process. The molecular evidence reveals that the electro-driven initial Ni(OH)2 first becomes disordered and finally is oxidized to NiOOH. When the OER occurs, the active oxygen species of NiOO* is observed to release O2. Compared with that of bare NF, the more disordered NiOOH from Ni(OH)2/Au/NF has a greater OER activity. These findings significantly advance the understanding of the OER mechanism on Ni-based catalysts, providing guidelines for the elaboration and optimization of future catalytic systems.