LAUSR

S-doped Fe/Ni oxide and Fe/Ni hydride oxide catalysts exhibit good oxygen evolution reaction (OER) performance. Nevertheless, the over-doping of S and the agglomeration of active sites still hinder the improvement of the performance of these catalysts. The S/O ratio regulation can optimize the electronic structure effectively so as to improve the OER performance of the catalysts, but few studies have focused on this study. Here, we find a facile room-temperature method to synthesize the unique 3D ultra-thin FeNiOS nanosheets with an adjustable S/O ratio for OER. The FeNiOS-NS catalysts exhibit excellent OER performance with an overpotential of 235 mV at 10 mA cm−2 and a small Tafel slope of 64.2 mV dec−1 in 0.1 M KOH, which originated from the sufficient exposure of the active Fe–Ni component and the optimized electronic structure due to the tunable S/O ratio. This study demonstrates a novel strategy to optimize the OER performance of Ni-based catalysts.