Abstract
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 h without decline. These results could open a new path for designing efficient and stable catalysts.
Ru/MoO2 catalyst with paired Ru–O–Mo sites improved the H2O dissociation by optimized H2O adsorption, and great alkaline HER performance was achieved. [Display omitted]
•The H2O adsorption ability significantly improves by the paired Ru–O–Mo sites ensemble.•The charge transfer from Ru to the O in Ru–O–Mo sites reduces the H2O dissociation barrier.•The Ru/MoO2 catalysts with Ru–O–Mo sites exhibited an excellent overpotential (16 mV) and stability (40 h) in alkaline HER.