Fabrication of Z-scheme CdTe/CaTiO3-x perovskite heterostructure with enhanced photocatalytic activity

Photoelectrochemical water splitting and pollutant degradation are promising technologies for the energy crisis and environmental remediation. In this study, a heterojunction system of oxygen vacancies mediated CaTiO₃ nanocubes (CaTiO_3-x) modified with CdTe (CdTe/CaTiO_3-x) was prepared using a simple hydrothermal method. Additionally, possible charge transfer pathways and the generation of active species are explored and analyzed using the Z-scheme photocatalytic mechanism. The CdTe/CaTiO_3-x heterostructure enhances photocatalytic activity due to its valence and conduction band structures that are more suitable for absorbing sunshine, higher e^-/h⁺ separation efficiency, stronger electronic conduction ability, and greater hydrophilicity. The greatest photocurrent density of 400 µA cm^-2 at 1.23 V vs. RHE is thus achieved by the CdTe/CaTiO_3-x photoelectrode among the four electrodes, which is four times greater than that of the CaTiO₃ photoelectrode. Also, about 84% of RhB degradation was attained by the CdTe/CaTiO_3-x within 1 h of reaction time. This work opens up the possibility of tuning perovskite-type semiconductor materials' photocatalytic activity using CdTe in order to make recyclable bifunctional photocatalysts.