Experimental method to explore the adaptation degree of type-II and all-solid-state Z-scheme heterojunction structures in the same degradation system

• Published in: Chinese journal of catalysis 2020-10, Vol.41 (10), p.1522-1534
• Main Authors: Huang, Zheao, Zhao, Shuo, Yu, Ying
• Format: Article
• Language: English
• Subjects: Photodegradation; TiO2-C3N4TiO2-C-C3N4; Type-II heterojunction semiconductor; Z-scheme heterojunction structure semiconductor
• ISSN: 1872-2067; 1872-2067
• DOI: 10.1016/S1872-2067(19)63495-9

TiO2 nanoparticles were prepared using the hydrothermal method and modified with C3N4 to synthesize a Type-II heterojunction semiconductor photocatalyst, TiO2-C3N4. In addition, a carbon layer was coated onto the TiO2 nanoparticles and the obtained material was uniformly covered on the surface of C3N4 to form an all-solid-state Z-scheme semiconductor photocatalyst, TiO2-C-C3N4. Through characterization by XRD, XPS, SEM, TEM, BET, photoelectrochemical experiments, UV-visible diffuse reflection, and PL spectroscopy, the charge transfer mechanism and band gap positions for the composite photocatalysts were analyzed. The Type-II and all-solid-state Z-scheme heterojunction structures were compared. By combining microscopic internal mechanisms with macroscopic experimental phenomena, the relationship between performance and structure was verified. Experimental methods were used to explore the adaptation degree of different photocatalytic mechanisms using the same degradation system. This study highlights effective photocatalyst design to meet the requirements for specific degradation conditions. The all-solid-state Z-scheme semiconductor TiO2-C-C3N4 and type-II heterojunction semiconductor photocatalyst TiO2-C3N4 were fabricated for comparison. Different photocatalysis mechanisms for the two photocatalysts were determined experimentally, which shed light on the design of a highly efficient photocatalyst for different degradation systems.