Synergizing copolymerization and thermal induction for carbon nitride: Reinforcing photocatalytic performance and mechanism insight

Abstract

Structure optimization of photocatalyst graphitic carbon nitride (CN) is still a key endeavor. CN nanosheets were prepared via a facile one-pot copolymerization process, incorporating electron-withdrawing groups 5-cyanopyrimidine (CPM) and melamine under calcination. The synergistic effect of molecular doping and thermal induction effectively modulates the intrinsic electronic and band structure of CN. The post-optimized sample (CNMCPM0.03–700) exhibits a higher reduction potential, reduced nanosheet thickness, stronger crystallinity, and enhanced electron-holes separation efficiency, compared to pristine CN (CNM). Notably, significant morphological and textural alterations were observed in the modified CNMCPMX-T samples. Consequently, a remarkable enhancement in visible-light photocatalytic H2 evolution and CO2 reduction performance was achieved. Specifically, the CNMCPM0.03–700 retained an H2 evolution rate of 166.4 µmol·h−1, which was 14.8-fold higher than that of CNM (11.3 µmol·h−1), along with a 31.6-fold increase in CO evolution efficiency. Molecular and textural engineering demonstrate their universal applicability for different comonomers. This study showcases the feasibility of synergizing thermal induction and copolymerization strategies for synthesizing high-efficiency CN-based photocatalysts with unique topology and structural precision.