Ru doping in Ni(OH)2 to accelerate water reduction kinetics for efficient hydrogen evolution reaction

Abstract

Water dissociation reaction (Volmer step) is the main restrictive factor that gives rise to the sluggish reaction kinetics for hydrogen evolution reaction (HER) in alkaline solution. In this paper, Ru doped Ni(OH)2 deposited on Ti mesh (abbreviated as TM) was synthesized by one-pot hydrothermal method. SEM, TEM, XRD, Raman, and XPS analysis indicated that both surface morphology and electronic structure had an apparent change, but phase structure maintained unchanged after Ru doping. HER activities of Ru doped Ni(OH)2/TM samples in 1.0 M KOH were investigated in detail. Ru doped Ni(OH)2/TM prepared with 0.2 mM RuCl3 precursor (denoted as Ru doped Ni(OH)2/TM-0.2) presented excellent HER performance with an overpotential of 135 mV at −10 mA/cm2 and the lowest Tafel slope of 63.7 mV/dec. This electrocatalyst also maintained long-term stability even operating for 15 h. Experimental results demonstrated that Ru doping into Ni(OH)2 could enhance charge transfer rate, increase electrocatalytically active surface area (ECSA) and, most importantly, accelerate Volmer step and also provide appropriate Ru active sites for hydrogen adsorption, which endowed Ru doped Ni(OH)2/TM-0.2 with superior HER activity and durability.