Visible Light-Driven Highly\nSelective CO₂ Reduction to CH₄ Using Potassium-Doped\ng‑C₃N₅

Abstract

Establishment\nof an efficient and robust artificial photocatalytic\nsystem to convert solar energy into chemical fuels through CO₂ conversion is a cherished goal in the fields of clean energy\nand environmental protection. In this work, we have explored an emergent\nlow-<i>Z</i> nitrogen-rich carbon nitride material g-C₃N₅ (analogue of g-C₃N₄) for\nCO₂ conversion under visible light illumination. A significant\nenhancement of the CH₄ production rate was detected for\ng-C₃N₅ in comparison to that of g-C₃N₄. Notably, g-C₃N₅ also showed\na very impressive selectivity of 100% toward CH₄ as compared\nto 21% for g-C₃N₄. The photocatalytic CO₂ conversion was performed without using sacrificial reagents.\nWe found that 1% K doping in g-C₃N₅ enhanced\nits performance even further without compromising the selectivity.\nMoreover, 1% K-doped g-C₃N₅ also exhibited better\nphotostability than undoped g-C₃N_5. We have\nalso employed density functional theory calculation-based analyses\nto understand and elucidate the possible reasons for the better photocatalytic\nperformance of K-doped g-C₃N₅.