Solid salt induced and activated semi-coke decorated carbon nitride with enhanced photocatalytic H₂ production

Homogeneous incorporation and carbon-based materials decoration in a photocatalyst are two pivotal approaches to enhance photoactivity. Herein, we proposed a solid salt-induced strategy for synthesizing a novel carbon-coupled and potassium-incorporated carbon nitride (SC/PHI_K) using activated semi-coke (SC) as the carbon source, and KCl as the salt template. The influence of SC and KCl content on the structural and photocatalytic performance of the SC_X1/PHI_KX2 composites was systematically investigated. The synergistic effects of activated SC coupling and KCl incorporation commendably enhance the separation and migration efficiency of photoexcited charge carriers, increase the specific surface area, and improve light absorption, thereby markedly boosting photocatalytic activity. Specifically, the optimized SC_0.05/PHI_K4 exhibited a 15-fold increase in photocatalytic H₂ evolution compared to pristine CN. Additionally, SC_0.05/PHI_K4 demonstrated excellent stability and reusability. An in-depth discussion of the mechanism underlying the enhanced photocatalytic activity was also proposed. These findings introduce a novel approach that involves the simultaneous incorporation of heterogeneous carbon materials and homogeneous alkali-metal ions into CN photocatalysts, thereby achieving efficient solar-to-chemical energy conversion.