Work-function-induced interfacial electron redistribution of MoO2/WO2 heterostructures for high-efficiency electrocatalytic hydrogen evolution reaction

The engineering of the electronic configurations of active sites, together with the production of more accessible active sites through heterostructure design, has been established as a forceful methodology for boosting water electrolysis performance. Herein, a facile approach is developed to fabricate well-dispersed MoO 2 and WO 2 nanoparticles with abundant heterointerfaces entrapped in N,P-doped carbon nanofibers (referred to as MoO 2 /WO 2 @N,P-CNFs hereafter) as hydrogen evolution reaction (HER) electrocatalysts in alkaline and acidic electrolytes. Extensive spectroscopic analyses and theoretical findings manifest that the heterointerface formed by the work function modulation of MoO 2 /WO 2 triggers the spontaneous electron redistribution from MoO 2 to WO 2 and a built-in electric field, which is essential to promote water adsorption, optimize the H-intermediate adsorption energy, result in the enhanced charge transfer efficiency, and ultimately increase the intrinsic HER activity. Simultaneously, the intimate confinement of MoO 2 /WO 2 heterostructures in the porous carbon substrate can restrain the active sites from unfavorable coarsening and detachment, thus ensuring facilitated HER kinetics and outstanding structural robustness. As a result, MoO 2 /WO 2 @N,P-CNFs exhibit superior catalytic HER performance in acidic and basic solutions, requiring 118 and 95 mV overpotentials to achieve 10 mA·cm −2 , respectively, surpassing a number of reported non-noble metal-based electrocatalysts. This work provides guidelines for the rational design and construction of special metallic heterocomponents with optimized interfacial electronic structure for various electrochemical technologies. Graphic abstract