Synthesis of mesoporous polymeric carbon nitride exhibiting enhanced and durable visible light photocatalytic performance

A thiourea precursor was employed to synthesize mesoporous carbon nitride (C₃N₄) by a thermal polycondensation process with high surface area SiO₂ and nanosphere SiO₂ as two types of hard templates. The resultant mesoporous C₃N₄ samples have high surface areas (105–112 m²/g) and mesopores with narrow sizes distribution (9.3 nm). Photocatalytic performance was evaluated by removal of NO in air under visible light irradiation. The results showed that mesoporous C₃N₄ samples exhibited significantly improved photocatalytic activity in comparison with bulk C₃N₄, which also exceeded that of N-doped TiO₂ and C-doped TiO₂. The activity enhancement can be ascribed to the synergistic effects of large surface area and pore volume, enhanced light-harvesting ability, increased redox potential, and reduced recombination of charge carriers. In addition to the high activity, the mesoporous C₃N₄ samples also showed high photochemical stability. The mesoporous C₃N₄ photocatalysts with enhanced and durable activity could provide a new efficient material for environmental pollution control.