Plasma-induced moieties impart super-efficient activity to hydrogen evolution electrocatalysts

Abstract

Abstract Having a high combustion value (1.4 × 108 J/kg) with an intrinsically green nature, hydrogen has been widely regarded as the next generation energy alternative to the conventional fossil fuels that have caused severe environmental issues associated with the rapidly increasing CO2 emissions, including global warming, sea level rising and species extinction. Thus, it is important to develop highly efficient and cost-effective catalysts for hydrogen generation. Herein, we fabricated a novel NiMoO4 catalyst on Ni foams, followed by NH3–plasma treatment to introduce NH2 functional groups, which were then transformed into –NH3 moieties during the HER process to afford a superb HER activity in alkaline solution, approaching the theoretical limit. The resultant NHx-NiMoO4 HER catalyst was demonstrated to be super-active with a record high HER performance (η @ 10 mA cm−2 = 18 mV, Tafel slope = 28.3 mV/decade) and promising for sea-water splitting. The theoretical studies suggest that NH3 moieties suffered from reorganization towards minimizing the energy barriers for both Volmer and Tafel/Heyrovsky steps. The plasma method may be extended to the design of novel catalysts for many other important chemical or electrochemical reactions.