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 TiO 2 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   μmol   h −1   g −1 under UV–vis irradiation when the ratio of the CdS nanoparticles to TiO 2 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–TiO 2 interface, and favorable reaction sites resulting from the porous structure .