Pyramid-like CdS nanoparticles grown on porous TiO2 monolith: An advanced photocatalyst for H2 production

Efficient production of H-2 via solar-light-driven water splitting by a semiconductor-based photocatalyst without noble metals is crucial owing to increasingly severe global energy and environmental issues. However, many challenges, including the low efficiency of H-2 evolution, low solar light absorption, excited electron-hole pair recombination, and slow transport of photoexcited carriers, must be resolved to enhance the H-2 photoproduction efficiency and photocatalyst stability. Here, a two-step method is used to synthesize advanced H-2-generating photocatalysts consisting of pyramid-like CdS nanoparticles grown on a porous TiO2 monolith, which show promising photocatalytic activity for the hydrogen evolution reaction. Furthermore, the stability of the photocatalysts is examined through long-term tests to verify their good durability. Without noble metals as cocatalysts, the photocatalyst can reach a high H-2 production rate of 1048.7 mu mol h(-1) g(-1) under UV-vis irradiation when the ratio of the CdS nanoparticles to TiO2 is 5 mol%. This unusual photocatalytic activity arises from the wide-region light adsorption due to the narrow band gap of CdS, effective separation of electrons and holes due to conduction band alignment at the CdS-TiO2 interface, and favorable reaction sites resulting from the porous structure. (C) 2017 Elsevier Ltd. All rights reserved.