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

• Published in: ChemistrySelect (Weinheim) 2024-03, Vol.9 (12), p.n/a
• Main Authors: Lan, Phung Thi, Hao, Nguyen Hoang, Cam, Le Minh
• Format: Article
• Language: English
• Subjects: 2,4-D photodegradation; Akaline hydrothermal treatment; g-C3N4; mechnism; visible light irradiation
• ISSN: 2365-6549; 2365-6549
• DOI: 10.1002/slct.202305026

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. TiO2/g‐C3N4 and 50 % mod.TiO2/g‐C3N4 composites were made by combining the treated Degussa P25 with g‐C3N4 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.TiO2 and g‐C3N4. Both ⋅OH, O2⋅− 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‐C3N4‐based photocatalysts may be employed, depending on the pH conditions, in the wastewater treatment. The bandgap of TiO2 Degussa P25 is lowered to 2.9 eV and its specific surface area is about 2.5 times larger after alkaline hydrothermal treatment. Treated Degussa is combined with g‐C3N4 to create a composite that has better light absorption properties and successfully prevents the recombination of photogenerated charges. The synthesized materials show an excellent photocatalytic capability in 2,4‐D degradation.