Carbon quantum dots-doped g-C3N4 nanocomposites with enhanced piezoelectric catalytic performance

Construction of charge transfer channel is a feasible way to enhance efficiency in catalysis applications. In this study, hydrothermally synthesized carbon quantum dots (CQDs) were deposited on g-C3N4 nanosheets via the coprecipitation calcination method to couple the piezoelectrical nature of g-C3N4 with the prominent charge transfer capability of CQDs, resulting in enhanced piezo-catalytic performance of the CQDs/g-C3N4 nanocomposites. Specifically, a 92.5% methylene blue degradation rate was achieved after constant stirring of the methylene blue (MB) solution in the presence of 50 mg CQDs/g-C3N4 for 30 min. As evidenced by electron density difference, the enhanced generation of reactive oxygen species (ROS) as the main mechanism for dye degradation was due to the enhanced surface area and increased number of reactive sites along with the existence of charge transfer channel, which was responsible for the dye degradation. Coupling CQDs with g-C3N4 nanosheets provides a new strategy of the construction of carbon-based nanocomposites towards promising piezo-catalytic applications. It also provides a new perspective for wastewater treatment on the dark environment.