Synergistically enhanced alkaline hydrogen evolution reaction by coupling CoFe layered double hydroxide with NiMoO4 prepared by two-step electrodeposition

Abstract

Exploiting cost-effective, highly efficient and stable alkaline electrocatalysts is a great challenge for the hydrogen evolution reaction (HER). Herein, NiMoO₄ and CoFe layered double hydroxide (CoFe LDH) with poor crystallinity were successively deposited on Cu nanowire (Cu NW) grown on Cu foam by a two-step electrodeposition process, which was verified by XRD, Raman, ATR-FTIR, XPS, SEM, TEM and HRTEM characterizations. The HER performance measurement in 1.0 M KOH solution showed the optimal CoFe LDH-60 s/NiMoO₄/Cu NW/Cu foam sample demonstrated prominent alkaline HER activity and long-term durability with an ultralow overpotential of 45 mV at −10 mA cm⁻² and a Tafel slope of 94.0 mV dec⁻¹, superior to the recently reported transition metal-based electrocatalysts. Further study clarified that the remarkable alkaline HER performance could be attributed to the strong synergistic effect between CoFe LDH-60 s and NiMoO₄ in favor of water adsorption/activation and optimizing hydrogen adsorption, and providing plentiful exposed active sites as well as an enhanced electron transfer process offered by the unique 1D nanostructure with Cu nanowire as the core. This work can provide a guidance for designing a highly active and stable electrocatalyst for hydrogen production.