Insights into the Role of Protonation in Covalent Triazine Framework-Based Photocatalytic Hydrogen Evolution

Covalent triazine frameworks (CTFs) are promising photocatalysts for hydrogen evolution. The current research focuses on optimizing the band structure and intrinsic charge separation efficiency of CTFs. Other influential factors, i.e., the water affinity and the interaction with the Pt co-catalyst, are rarely investigated. Herein, we provide a facile protonation strategy for significantly improving the photocatalytic performance of CTFs. The protonated CTFs (P-CTF) can exhibit a hydrogen evolution rate of 6595 mu mol g(-1) h(-1), which is 7.14 times that of pristine CTFs. The main contribution of protonation is to improve the interaction among the P-CTF, H2O molecules, and Pt co-catalyst, which can increase the H2O concentration around the active catalytic sites, thus facilitating the transfer of the photogenerated electron from the Pt co-catalyst to the H2O. Our results provide some insight into the role of protonation in promoting the photocatalytic hydrogen evolution performance.