Electrocatalytic hydrogen evolution reaction (HER) in alkaline media is a promising electrochemical energy conversion strategy. Ruthenium (Ru) is an efficient catalyst with a desirable cost for HER, however, the sluggish H2O dissociation process, due to the low H2O adsorption on its surface, currently hampers the performances of this catalyst in alkaline HER. Herein, we demonstrate that the H2O adsorption improves significantly by the construction of Ru-O-Mo sites. We prepared Ru/MoO2 catalysts with Ru-O-Mo sites through a facile thermal treatment process and assessed the creation of Ru-O-Mo interfaces by transmission electron microscope (TEM) and extended X-ray absorption fine structure (EXAFS). By using Fourier-transform infrared spectroscopy (FTIR) and H2O adsorption tests, we proved Ru-O-Mo sites have tenfold stronger H2O adsorption ability than that of Ru catalyst. The catalysts with Ru-O-Mo sites exhibited a state-of-the-art overpotential of 16 mV at 10 mA cm -2 in 1 M KOH electrolyte, demonstrating a threefold reduction than the previous bests of Ru (59 mV) and commercial Pt (31 mV) catalysts. We proved the stability of these performances over 40 hours without decline. These results could open a new path for designing efficient and stable catalysts.

Directly using solar energy to realize photocatalytic reduction of CO2to hydrocarbon fuels is an effective tactics to solve the energy crisis and carbon emission. Although graphite carbon nitride (g‐C3N4) has been widely studied as a star photocatalyst for CO2reduction, the extremely fast charge recombination rate seriously limits its performance. Loading suitable co‐catalysts to construct an effective junction is considered an efficient way to solve this issue and promote photocatalytic performance. In this work, metallic molybdenum dioxide (MoO2) is dispersed on g‐C3N4nanosheets to construct a Schottky junction photocatalyst. The Schottky junction between MoO2and g‐C3N4induces efficient charge separation and transfer. As a result, the optimal MoO2/g‐C3N4Schottky junction photocatalyst exhibits a 15 times higher CH4yield and five times higher CO yield compared with pure g‐C3N4. This article provides a new route to construct a Schottky junction for boosting photocatalytic activity.