Electronic modulation of novel W18O49 nanoshuttles for efficient hydrogen evolution reaction

Abstract

Research on transition metal oxides for hydrogen evolution reaction (HER) is challenging due to their poor electrical conductivity and weak hydrogen adsorption. In this paper, a class of W₁₈O₄₉ nanoshuttles (NSs) with highly bifurcated structure at both ends were synthesized via a hydrothermal method for highly efficient HER. By simply introducing Nb and Pt components, W₁₈O₄₉ can achieve optimal hydrogen adsorption through electronic modulation. The optimized NbPt/W₁₈O₄₉ NSs show an extremely low overpotential of 37 mV to obtain 10 mA cm^-2 and an unprecedented small Tafel slope of 23 mV dec^-1, superior to commercial Pt/C. The NbPt/W₁₈O₄₉ NSs can endure long-term stability for 18 h with negligible morphology change and performance degradation. Based on the surface valence band spectra of x-ray photoelectron spectroscopy and density functional theory calculations, the improved HER activity is closely related to the optimization of hydrogen binding energy on active sites and activation of inert O sites of W₁₈O₄₉. This study opens a facile avenue of electronic modulation to promote electrocatalytic performance.