Disordered layers on WO₃ nanoparticles enable photochemical generation of hydrogen from water

Abstract

Tailored defects on a semiconductor surface can provide active catalytic sites and effectively tune the electronic structure for suitable optical properties. Herein, we report that surface modification of WO₃ with a disordered layer enables the photochemical hydrogen production from water. A simple room temperature solution process with lithium-ethylenediamine (Li-EDA) alters the surface of WO₃ with localized defects that form a thin disordered layer. Both structural and optical characterization reveal that such a disordered layer induces an upshift in the Fermi level and the elevation of the conduction band of WO₃ above the hydrogen reduction potential. Using an alkaline sacrificial agent, Li-EDA treated WO₃ shows a co-catalyst-free photochemical hydrogen evolution rate of 94.2 μmol g⁻¹ h⁻¹ under simulated sunlight. To the best of our knowledge, this is the first example of using WO₃ as a direct photocatalyst for hydrogen generation from water via simple surface defect engineering.