Heterostructured graphitic-carbon-nitride-nanosheets/copper(I) oxide composite as an enhanced visible light photocatalyst for decomposition of tetracycline antibiotics

A heterostructured graphitic-carbon-nitride-nanosheets/copper(I) oxide (g-C3N4 nano sheets/Cu2O) composite was successfully prepared using a facile precipitation method by combining g-C3N4 nanosheets with Cu2O particle, which was successfully used as an visible-light photocatalyst for the degradation of tetracycline (TC) antibiotics. It is found that this composite had higher photocatalytic activity than the Cu2O as well as the g-C3N4 nanosheets. Especially, the 30 wt% g-C3N4 nanosheets/Cu2O composite showed the highest photocatalytic activity and 92.1% of TC was degraded within 100 min and 83.3% of total organic carbon (TOC) was removed after the reaction for 120 min. In addition, it showed an excellent reusability, and the severe photocorrosion issue of Cu2O was suppressed significantly by combining it with g-C3N4 nanosheets. The high photodegradation efficiency of g-C3N4 nanosheets/Cu2O composite could be ascribed to the efficient interfacial charge transfer at the p-n heterojunction and synergistic effect between Cu2O and g-C3N4 nanosheets with the enhanced separation efficiency of photogenerated e−-h+ pairs. In addition, the active species trapping experiments confirmed that the photo-generated h+ and O2− were the main active species involved in the TC degradation under visible light.