Enhanced Driving Force and Charge Separation Efficiency of Protonated g‑C3N4 for Photocatalytic O2 Evolution

• Published in: ACS catalysis Vol. 5; no. 11; pp. 6973 - 6979
• Main Authors: Ye, Chen, Li, Jia-Xin, Li, Zhi-Jun, Li, Xu-Bing, Fan, Xiang-Bing, Zhang, Li-Ping, Chen, Bin, Tung, Chen-Ho, Wu, Li-Zhu
• Format: Journal Article
• Language: English
• Published: American Chemical Society 06.11.2015
• Subjects: g-C3N4; charge separation efficiency; protonation; band structure; photocatalytic water oxidation
• DOI: 10.1021/acscatal.5b02185
• ISSN: 2155-5435

Photocatalysts based on g-C3N4 by loading cocatalysts or constructing heterojunctions have shown great potential in solar-driven water oxidation. However, the intrinsic drawbacks of g-C3N4, such as poor mass diffusion and charge separation efficiency, remain as the bottleneck to achieve highly efficient water oxidation. Here we report a simple protonation method to improve the activity of g-C3N4. Studies using valence band X-ray photoelectron spectra and steady-state and time-resolved spectroscopy reveal that the promotion of catalytic ability originates from the higher thermodynamical driving force and longer-lived charge separation state, which may provide guidance in designing efficient polymeric semiconductor photocatalysts with desirable kinetics for water oxidation.