Visible-light-driven Li/C co-doped PCN for enhanced photocatalytic hydrogen evolution

The Li and C co -doped polymeric carbon nitride (PCN) are successfully prepared using a facile calcination process. The construction of C C and Li N bonds, coupled with improved optical absorption, enhanced π bond delocalization and effective electron-hole pair separation, significantly advances the photocatalytic activity under visible light irradiation. The improved crystallinity, hydrophilicity and increased S BET are also beneficial for enhancing photocatalytic activity. As a result, the apparent quantum yield (AQY) of the optimal samples for H 2 evolution achieves values of 19.6% at 450 nm, 13.0% at 500 nm, and 4.0% at 550 nm, far surpassing the majority of previously reported PCN-based photocatalysts. Additionally, NaCit and KCit are also incorporated into the PCN structure via similar synthetic routes, underscoring the versatility of the present approach. Our findings shed light on an effective co-doping design strategy to foster synergistic interactions in the development of high-efficiency light-harvesting semiconductors. • Li/C co-doped PCN was successfully prepared to modulate the electronic structure. • NaCit and KCit are also adopted to underline the versatility of the approach. • Carrier separation efficiency and optical absorption range are greatly promoted. • Ultrahigh AQE for PHE were recorded under visible light range. • DFT simulations confirm band gap narrowing and enhanced carrier migration.