NiCr-LDH–Co nanosheets on nickel foam as efficient oxygen evolution electrocatalysts in alkaline media

Abstract

The exploration of efficient, stable, and economical electrocatalysts for oxygen evolution reaction (OER) is of great significance and challenge for the development of renewable energy. A series of Ni-based layered double hydroxides (LDHs) have been explored as promising electrocatalysts for OER on account of their earth abundance, low overpotential, and super stability. However, the low electrical conductivity of LDHs cannot satisfy the progressive requirements of water splitting. Herein, we introduce a template strategy to synthesize trimetallic nickel-chromium LDH–cobalt (NiCr-LDH–Co) nanosheets on nickel foam (NiCr-LDH–Co/NF) without any binders as efficient catalysts for OER. Compared with the reported NiCoCr-LDHs synthesized by one-step, our NiCr-LDH–Co/NF delivered a lower overpotential of 229.4 mV at 50 mA cm⁻², which is even lower than that of all the reported bimetallic nickel-based LDHs (NiFe-LDH, NiCo-LDH, NiMn-LDH, NiTi-LDH, NiV-LDH, etc.) and the precious RuO₂ catalyst. Furthermore, the NiCr-LDH–Co/NF was maintained for at least 24 h at a high current density of 50 mA cm⁻² without much deviation in 1 M KOH solution. The effective integration of the layered structures of LDH and the high electronic conductivity of the Co element endow NiCr-LDH–Co/NF remarkable catalytic ability for the OER process. Furthermore, the strategy expands the possibility for improving the catalytic activity of trimetallic LDHs as OER catalysts.