“One Stone Five Birds” Plasma Activation Strategy Synergistic with Ru Single Atoms Doping Boosting the Hydrogen Evolution Performance of Metal Hydroxide

Layered metal hydroxides (LMHs) are promising catalysts for oxygen evolution reaction. However, the hydrogen evolution reaction (HER) activity of LMHs is unsatisfactory due to their poor conductivity and limited active sites. Herein, taking Ni(OH) 2 as demonstration, a novel “one stone five birds” plasma activation strategy synergistic with Ru single atoms (Ru SAs) doping is developed to boost the HER activity of Ni(OH) 2 by constructing heterostructured β-Ni(OH) 2 /Ni-Ru SAs nanosheet arrays (NSAs). Benefiting from the structural/compositional features and optimized electronic state, the as-obtained β-Ni(OH) 2 /Ni-Ru SAs NSAs exhibit splendid HER activity with a low overpotential of 16 mV at 10 mA cm −2 and a small Tafel slope of 21 mV dec −1 in alkaline solution. Excellent HER performance in alkaline seawater and neutral solutions are also demonstrated by the β-Ni(OH) 2 /Ni-Ru SAs NSAs. The plasma activation and Ru SAs doping play important roles in enhancing water adsorption and accelerating the kinetics of water dissociation. Density functional theory (DFT) calculations reveal that the introduction of Ru SAs in the system facilitates the generation of surface OH vacancies for providing more active sites as well as decreases the antibonding state density of the generated mid-gap state for enhancing H adsorption strength toward the optimal range.