LAUSR

Abstract The main energy consumption of industrial water electrolysis is electric energy, which accounts for ca. 80% of the total cost of water electrolysis. Developing highly efficient bifunctional electrocatalyst for both hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) is essential to reduce the energy consumption. Herein, nickel foam (NF)-supported NiCoP nanorod array catalyst is prepared and used for HER and OER. Not only at a small current density (10 mA/cm2), but also at the commercially required high current density (≥500 mA/cm2), NiCoP/NF catalyst shows excellent bifunctional properties with extremely low overpotential and high stability. Small overpotentials of 60 and 253 mV are needed to drive the current density of 10 mA/cm2 for HER and OER, respectively, and the cell voltage of overall water splitting is only 1.55 V. At the high current density of 500 mA/cm2, the overpotentials are 180 and 365 mV, and the corresponding cell voltage is only 1.83 V. Furthermore, the cell voltage hardly changes within 24 h of overall water splitting test, which makes the catalyst have promising applications in the industrial water electrolysis. The high performance of NiCoP/NF outperforms the commercial RuO2-Pt/C couple and most of the bifunctional Ni/Co-based catalysts reported so far.