Constructing a NiCu/C/NiCu Interface for Alkaline Saline Water Electrolysis

Abstract

Abstract Interface engineering is a useful way to fabricate nonprecious-based electrocatalyst materials for easy overall water splitting (OWS), which is of great importance for renewable hydrogen energy production. Herein, we designed a needle-like catalyst by a low-temperature CVD method using NiCu alloy nanoparticles evenly embedded in the graphene shell, resulting in a large-scale NiCu/C/NiCu interface. The few-layer graphene prevents the NiCu alloy nanoparticles from melting and growing and increases the number of interfaces. Meanwhile, the C layer coated on the surface of the NiCu alloy hinders the erosion of Cl– to the catalyst, showing excellent stability in the overall water splitting. The HER and OER overpotentials of the needle-like catalyst in a 1 M KOH solution were 53.8 and 298.5 mV (10 mA cm–2), respectively, and the HER and OER overpotentials in a 1 M KOH+0.5 M NaCl solution were 38.4 and 304.1 mV (10 mA cm–2), respectively. Assembled with two electrodes in a cell for saline water splitting, it reaches the current density of 100 mA cm–2 at an operating voltage of 1.86 V. Additionally, it also shows superb stability for 65 h at a high current density.