Semiconductor-metal-semiconductor TiO2@Au/g-C3N4 interfacial heterojunction for high performance Z-scheme photocatalyst

Tingkai Hong; Shoaib Anwer; Ju Wu; Chonghai Deng; Hongmei Qian

doi:10.3389/fchem.2022.1050046

Semiconductor-metal-semiconductor TiO₂@Au/g-C₃N₄ interfacial heterojunction for high performance Z-scheme photocatalyst

Front Chem. 2022 Oct 21:10:1050046. doi: 10.3389/fchem.2022.1050046. eCollection 2022.

Authors

Tingkai Hong¹, Shoaib Anwer², Ju Wu³, Chonghai Deng¹, Hongmei Qian⁴

Affiliations

¹ School Energy Materials and Chemical Engineering, Hefei University, Hefei, China.
² Department of Mechanical Engineering, Khalifa University of Science and Technology, Abu Dhabi, United Arab Emirates.
³ Key Laboratory of Biomimetic Sensor and Detecting Technology of Anhui Province, West Anhui University, Lu'An, China.
⁴ Department of Architecture and Civil Engineering, West Anhui University, Lu'An, China.

Abstract

We designed an edge-sites 2D/0D/2D based TiO₂@Au/g-C₃N₄ Z-scheme photocatalytic system consists of highly exposed (001) TNSs@Au edge-site heterojunction, and the Au/g-C₃N₄ interfacial heterojunction. The designed photocatalyst was prepared by a facile and controlled hydrothermal synthesis strategy via in-situ nanoclusters-to-nanoparticles deposition technique and programable calcination in N₂ atmosphere to get edge-site well-crystalline interface, followed by chemically bonded thin overlay of g-C₃N₄. Photocatalytic performance of the prepared TNSs@Au/g-C₃N₄ catalyst was evaluated by the photocatalytic degradation of organic pollutants in water under visible light irradiation. The results obtained from structural and chemical characterization conclude that the inter-facet junction between highly exposed (001) and (101) TNSs surface, and TNSs@Au interfacial heterojunction formed by a direct contact between highly crystalline TNSs and Au, are the key factors to enhance the separation efficiency of photogenerated electrons/holes. On coupling with overlay of g-C₃N₄ 2D NSs synergistically offer tremendous reactive sites for the potential photocatalytic dye degradation in the Z-scheme photocatalyst. Particularly in the designed photocatalyst, Au nanoparticles accumulates and transfer the photo-stimulated electrons originated from anatase TNSs to g-C₃N₄ via semiconductor-metal heterojunction. Because of the large exposed reactive 2D surface, overlay g-C₃N₄ sheets not only trap photoelectrons, but also provide a potential platform for increased adsorption capacities for organic contaminants. This work establishes a foundation for the development of high-performance Z-scheme photocatalytic systems.

Keywords: Au/TiO2; G-C3N4; Z-scheme photocatalysts; interfacial coupling; photocatalytic degradation.