Interface engineering of NiO/RuO2 heterojunction nano-sheets for robust overall water splitting at large current density

It is of great potential to develop efficient and robust Ru based bifunctional catalysts for water electrolysis. In this work, NiO/RuO2 heterojunction nano-sheets in situ grown on nickel foam (NiO/RuO2/NF) is successfully prepared, which shows good activity and stability for both oxygen and hydrogen evolution reaction (OER and HER). For overall water splitting (OWS), it only needs 1.44 V to obtain 10 mA cm−2 in 1.0 M KOH solution. Notably, it can work for 72 h at ± 1,500 mA cm−2 toward OER, HER and OWS with small activity decrease. Under simulated industrial conditions, 1.90 V is needed to drive 1,500 mA cm−2, and it also can work steadily for 72 h. The reason could be attributed to the heterogeneous interface coupling effect and nano-sheets with rough surface directly grown on NF. Hence, this work provides a feasible strategy for developing robust bifunctional Ru based water splitting catalysts.