Crystalline Ni(OH)₂/Amorphous NiMoO<i>_x</i> Mixed‐Catalyst with Pt‐Like Performance for Hydrogen Production

Abstract

Abstract The achievement of effective alkaline hydrogen production from water electrolysis is an active field of research. Herein, an integrated electrode composed of crystalline Ni(OH) 2 and amorphous NiMoO x is fabricated onto nickel foam (denoted as Ni(OH) 2 –NiMoO x /NF). The hydrogen evolution reaction (HER) kinetics are optimized along with phase transformation process during soaking operation. An overpotential of 36 mV to drive 10 mA cm −2 along with the low Tafel slope of 38 mV dec −1 reveals the catalyst's excellent HER performance and a Heyrovsky‐step‐controlled HER mechanism. When assembled into a urea‐assisted water electrolyzer, a voltage of 1.42 V can reach 10 mA cm −2 . Further experiments and Fourier transform infrared spectroscopy (FTIR) results illustrate the synergy effect between crystalline and amorphous areas and the optimized water dissociation step. Crystalline Ni(OH) 2 serves as the scissor for water dissociation in an alkali environment to produce H*, while the amorphous NiMoO x layer serves as the location for H* adsorption and H 2 desorption.