Synergism between chemisorption and unique electron transfer pathway in S-scheme AgI/g-C3N4 heterojunction for improving the photocatalytic H2 evolution

• Published in: Journal of colloid and interface science Vol. 631; pp. 269 - 280
• Main Authors: Shang, Yanyan, Fan, Huiqing, Yang, Xueya, Dong, Wenqiang, Wang, Weijia
• Format: Journal Article
• Language: English
• Published: Elsevier Inc 01.02.2023
• Subjects: Built-in electric field; g-C3N4; H2 production; S-scheme heterojunction; g-C3N4; H2 production; Built-in electric field; S-scheme heterojunction
• ISSN: 0021-9797; 1095-7103
• DOI: 10.1016/j.jcis.2022.10.168

[Display omitted] •Surface nitrogen vacancy is instrumental in the chemisorption and activation of H2O.•Surface nitrogen vacancy and extended photocarrier lifetime has improved H2 production.•S-scheme band of AgI/g-C3N4 is conjectured by the experiments and DFT calculations. AgI/g-C3N4 S-scheme heterojunction with a unique electron transfer pathway was developed as a catalyst for H2 evolution. We discussed the behavior of chemisorption and photoexcited charge carriers in photocatalytic reduction on the S-scheme AgI/g-C3N4 heterojunction. It was demonstrated that the path of charge transfer mediated by S-scheme AgI/g-C3N4 heterojunction was favorable for the improvement of electron utilization in photocatalysis. The advantage of S-scheme heterojunction was that the holes in the valence band (VB) of g-C3N4 could recombine with the electrons in the conduction band (CB) of AgI due to the built-in electric field. Electrons on the CB of g-C3N4 and holes on the VB of AgI were preserved for further photocatalytic reaction. Therefore, a distinctive electron transfer pathway was introduced in the S-scheme heterojunction. In addition, the lifetime of charge carriers was prolonged, and the reduced ability of electrons was increased as compared to reference g-C3N4. It not only decreased the energy required for electron excitation, but also reduced the energy consumption for the charge transfer. This paper provided a new strategy to improve the utilization of photogenerated electrons and chemisorption of water for photocatalytic H2O splitting.