Construction of g-C3N4/Ag/TiO2 Z-scheme photocatalyst and Its improved photocatalytic U(VI) reduction application in water. (26th April 2022)

• Record Type: Journal Article
• Authors: Liu, Yuelin; Yuan, Yilei; Ni, Shangyuan; Liu, Jun; Xie, Shuibo; Liu, Yingjiu
• Is Part Of: Water science and technology. Volume 85:Number 9(2022)
• Page Start: 2639
• Page End: 2651
• Publication Date: 2022-04-26
• Subjects: g-C3N4 -- photocatalysis -- TiO2 -- U(VI) reduction -- Z-scheme; Water -- Pollution; Sewage -- Purification; Water quality management; Periodicals; 628.168
• DOI: 10.2166/wst.2022.139
• Languages: English
• ISSNs: 0273-1223

Abstract

Abstract: The reduction of soluble U(VI) to insoluble U(IV) by photocatalytic technology is considered to be a valid method to remove U(VI) from water. Herein, g-C3 N4 /Ag/TiO2 Z-scheme heterojunction was synthesized for photocatalytic U(VI) reduction application. The SEM, XRD and XPS characterization results showed that a ternary g-C3 N4 /Ag/TiO2 composite photocatalyst was synthesized successfully. g-C3 N4/ Ag/TiO2 exhibited excellent photocatalytic reduction performance for U(VI) under visible light irradiation. After 30 min irradiation, the removal rate of U(VI) was above 99%. XPS indicated that the majority of U(VI) on the surface of g-C3 N4 /Ag/TiO2 was reduced to U(IV). In addition, the photocatalytic activity of g-C3 N4 /Ag/TiO2 has been kept significantly after five rounds of experiments, indicating good stability. g-C3 N4 /Ag/TiO2 exhibited better photocatalytic reduction of U(VI) under visible light irradiation, which is mainly ascribed to Z-scheme photocatalytic mechanism assisted by the LSPR effect (Local Surface Plasmon Resonance). Ag with plasmon resonance effect on the loading has a strong absorption of photon energy. In addition, an intermediate charge transfer channel is formed between Ag and the semiconductor to inhibit the combination of photogenerated electrons and holes, resulting in a significant increase in the photocatalytic activity of the photocatalyst. This idea has some significance in design of other composite photocatalytic systems. HIGHLIGHTS: Z-scheme heterojunction was synthesized successfully. g-C3 N4 /Ag/TiO2 exhibited excellent photocatalytic reduction performance for U(VI) under visible light irradiation. g-C3 N4 /Ag/TiO2 exhibited better photocatalytic reduction of U(VI) under visible light irradiation, which is mainly ascribed to Z-scheme photocatalytic mechanism assisted by the LSPR effect.