Study on the Synthesis and Photocatalytic Performance of Modified TiO₂ Supported by G‐C₃N₄ in the Degradation of 2,4‐Dichlorophenoxyacetic Acid

The impact of alkaline hydrothermal treatment on the structure and morphology of Degussa P25 was evaluated. The modification results in a larger surface area, which improves 2,4‐dichlorophenoxyacetic acid (2,4‐D) adsorption capacity and has a remarkable effect on the 2,4‐D photocatalytic degradation. The 30 % mod. TiO 2 /g‐C 3 N 4 and 50 % mod.TiO 2 /g‐C 3 N 4 composites were made by combining the treated Degussa P25 with g‐C 3 N 4 at mass ratios of 30 % and 50 %. Using XRD, SEM, EDX, BET, UV‐vis DRS, and PL, the synthesized materials were physically characterized. When compared to their pure components, the composites show a longer “lifetime” of charge carriers and a reduced energy band gap. The 2,4‐D degradation under visible light irradiation (λ>400 nm) was used to assess their photocatalytic activity. The influence of pH and 2,4‐D initial concentration were investigated. The enhanced 2,4‐D degradation efficiency of more than 80 % is ascribed to the cooperative photocatalytic action of mod.TiO 2 and g‐C 3 N 4 . Both ⋅OH, O 2 ⋅ − radicals and h + were the ROS dominating the degradation of 2,4‐D under investigated experimental circumstances. The 2,4‐D photocatalytic degradation follows pseudo‐first order kinetics. The findings of this work indicate that Degussa P25/g‐C 3 N 4 ‐based photocatalysts may be employed, depending on the pH conditions, in the wastewater treatment.