Steering charge kinetics in W2C@C/TiO2 heterojunction architecture: Efficient solar-light-driven hydrogen generation

Abstract

The constructing of functional materials with well-defined nanostructure, showing efficient charge separation and transportation properties, has been intensively and in depth investigated to fabricate catalysts for H2 generation from solar-driven water reduction. Here we demonstrate that loading W2C@C structure in which each W2C nanoparticle (NP) is wrapped by carbon shell on surface of hollow TiO2 microspheres (HTMs) can enhance the separation of photogenerated electron-hole pairs by building an internal electric field in W2C@C/HTMs composite structure and act as the reaction active sites for water reduction. As expected, the optimized W2C@C/HTMs construction exhibits the highest photocatalytic H2 generation rate of 6.91 mmol h−1 g−1 under simulated solar light illumination, over 20 times larger than that of bare HTMs. The underlying mechanism has been investigated from the perspective of photochemistry and photophysics based on a series of characterization techniques, which suggests that W2C@C can effectively steer the charge kinetics, maximizing the charge carriers’ separation.