摘要： The development of highly effective metal-free photocatalysts in place of traditional photocatalysts is of great significance for environmental remediation by utilization of solar energy. In this work, a new 2D carbon/g-C3N4 metal-free photocatalyst was designed and fabricated via one-step thermal treatment of cyanamide and spent tea leaves (STL). The as-prepared samples were fully characterized and the results revealed that carbon nanosheets are evenly attached on the surface of g-C3N4 by chemical bonds rather than simple physical stacking, which is beneficial to the strong interface interaction. The intimate interfacial bonding of carbon materials with g-C3N4 exhibit enlarged specific surface area, broadened photo-response range, efficient photo-induced electron migration as well as high stability. Thus, the carbon/g-C3N4 photocatalyst showed remarkable enhanced photocatalytic activities in the degradation of antibiotic ciprofloxacin (CIP) in aqueous solution and gaseous benzene than that of pristine g-C3N4 under visible light. Furthermore, a possible photocatalytic mechanism for the improved photocatalytic performance over carbon/g-C3N4 nanocomposites was proposed. This research work can promote the exploration on facile synthesis of total metal-free carbon/g-C3N4 photocatalysts with biomass as the carbon source and its application in environmental pollutants elimination.