Z-scheme photocatalyst Pt/GaP-TiO2-SiO2:Rh for the separated H2 evolution from photocatalytic seawater splitting

Heterojunction Pt/GaP-TiO2-SiO2:Rh (PGTSR) photocatalyst with the uniform spherical morphology (20 nm) possessed the high Ti3+ defects and oxygen vacancy (VO) sites in TiO2-SiO2:Rh composite which intimately contacted with GaP to form a Z-scheme photocatalyst. The PGTSR exhibited high photoactivity for pure water and artificial seawater splitting without sacrificial agents in single reactor under 4 -h simulated sunlight irradiation. The hydrogen/oxygen evolution rates (HER/OER) reached 80.1/41.2 mu mol.g(-1) and 94.0/45.1 mu mol.g(-1) in pure and artificial seawater splitting, respectively. The separated H-2 evolution from O-2 through the photocatalytic artificial seawater splitting was also carried out in a twin photoreactor, which was divided by a Neosepta membrane with IO3-/I- shuttle mediator and used commercial WO3 as O-2-photocatalyst, was achieved with HER/OER of 41.5/26.1 mu mol.g(-1) after 4 -h simulated sunlight irradiation. This work demonstrated a new construct of Z-scheme photocatalyst as well as the improvement of artificial photosynthesis system for overall photocatalytic seawater splitting.

Automated summary

This study demonstrated the high photoactivity of the Z-scheme photocatalyst PGTSR for splitting pure water and artificial seawater, achieving significant hydrogen/oxygen evolution rates without sacrificial agents under simulated sunlight. The separated H-2 evolution from O-2 through the photocatalytic artificial seawater splitting in a twin photoreactor also showed promising results.