Continuous 3D-nanopatterned Ni–Mo solid solution as a free-standing electrocatalyst for the hydrogen evolution reaction in alkaline medium

Abstract

To date, researchers have shown that nanostructured solid solutions of transition metal electrocatalysts can improve hydrogen evolution reaction (HER) activity in alkaline media. However, there are few reports that focus on mass producing efficient electrocatalysts for the HER based on continuous 3-dimensional (3D) nanopatterning. Herein, a 3D-nanopatterned solid solution of Ni-Mo is synthesized to provide efficient electrocatalytic activity in alkaline electrolytes. Experimentally, it is found that the electrocatalytic active surface area (ECSA) is 65 times higher than 2D Ni-Mo. Additionally, the charge transfer resistance (Rct) of 3D Ni-Mo (0.6 Ω) is 16 times lower than 2D Ni-Mo (10.3 Ω), which shows that 3D Ni-Mo allows the fast transport of ions and facilitates the H* desorption process; thus, the above contributes to the improved kinetics for HER activity. Moreover, the 3D-nanopatterned Ni-Mo electrocatalyst requires a minimum overpotential of 39 mV to achieve a 10 mA/cm² current density, which is very close to the benchmark Pt/C electrocatalyst (30 mV) for the HER in alkaline media. In addition, 3D-nanopatterned Ni-Mo electrocatalyst exhibits 94.7 % Faradaic efficiency during HER. The as-prepared 3D-nanopatterned Ni-Mo is a free-standing electrocatalyst that can be synthesized at the inch scale or even larger and will be useful for practical applications in future renewable energy devices.