Fabrication and Assessment of Co-TiO2/Ag3PO4 Z-Scheme Photocatalyst for Improved Methylene Blue Degradation

Water resources are crucial for human life. However, current water resource treatment methods have limitations. In this regard, photocatalysis is a promising water resource treatment technology with a simple operation, green environmental protection, and high economic benefits. Therefore, this study prepared a Co-TiO₂/Ag₃PO₄ (CTAP) photocatalyst for the treatment of water resources. Here, a Co-TiO₂/Ag₃PO₄ photocatalyst was prepared using a hydrothermal method combined with calcination. Under visible light irradiation, the methylene blue (MB) degradation degree of CTAP composite reached 96.4% within 14 min, and the degradation rate constant was 0.23516 min^–1. These reaction rates are 137 and 3.4 times higher than those of pure TiO₂ and Ag₃PO₄ samples, respectively. Thus, doping and heterojunctions significantly improved the photocatalytic performance of CTAP composites, primarily due to grain size reduction of TiO₂ after Co²⁺ doping. The formation of a close interfacial connection with Ag₃PO₄ increased the active site of the reaction and promoted the transfer of photogenerated charges, thus improving the photocatalytic performance of CTAP composites. According to the photocatalytic capture experiments of the active species, e^-, h⁺, ^•O^2–, and ^•OH play a common role in the degradation of MB. This paper provides insights into the design and preparation of a Z-scheme photocatalyst that can be considered for the degradation of pollutants in water.