Two-photon induced NIR active core-shell structured WO3/CdS for enhanced solar light photocatalytic performance

Near-infrared (NIR) light utilization in the photoreduction of water to H-2 remains a great challenge. Here we show an interesting design of NIR-driven photocatalyst via a two-photon absorption process by exploiting the electron-storage peculiarity of oxygen-deficient WO3. In the core-shell structured WO3/CdS, the WO3 core absorbs ultraviolet (UV)-visible and NIR photons successively and transfer excited electrons to the UV-visible light activated CdS shell for H-2 generation. The core-shell structure effectively hinders the consumption of the photo-generated charges on the surface of WO3. With the absence of cocatalyst, the WO3/CdS heterojunction presents an unprecedented H-2 generation rate of 65.98 and 14.84 mmol g(-1) h(-1) under solar light irradiation and in the NIR region, respectively. The solar-to-hydrogen conversion efficiency under simulated solar light irradiation reaches as high as 3.00 %. This work proposes a new approach to profiting the electron-storing WO3-like materials for designing solar light activated photocatalysts.