Enhanced photocatalytic activity of carbon nitride nanosheets via alkali metal ion doping

Abstract

Photocatalytic degradation of pollutants is one of the most promising strategies for addressing environmental issues associated with wastewater from textile and other dyeing industries. Graphitic carbon nitride (g-C₃N₄) has emerged as a prospective visible-light photocatalyst in this field due to its various advantages. However, pristine g-C₃N₄ often exhibits limited activity. To enhance the performance of g-C₃N₄, alkali metal ion doped g-C₃N₄ was prepared using a simple one-step thermopolymerization method. Characterization and analysis of the samples revealed that the obtained doped photocatalysts exhibited enhanced visible-light photocatalytic degradation activity. This is attributed to the reduction in grain size, which provides more active sites, extended visible-light absorption, a reduced bandgap, and more efficient electron transfer. Notably, due to the optimal adjustment of the microstructure and electronic structure, K⁺ doped g-C₃N₄ demonstrated the highest photocatalytic performance with a degradation rate of 89.1%, significantly surpassing the efficiency of pristine g-C₃N₄ (72%). These results demonstrated that the approach of incorporating alkali metal ions into g-C₃N₄ has the potential for facilitating high-performance photodegradation for organic pollutant removal.