Synthesis of free-metal composites g-CN/GQDs with enhanced photocatalytic degradation of tetracycline

Developing inexpensive and environmentally friendly no-metal photocatalyst is a promising strategy to addressing environmental issues. In this work, the metal-free catalyst g-CN/GQDs was synthesized through one-pot co-sintering method. The as-prepared photocatalysts showed enhanced photocatalytic activity for tetracycline (TC) degradation. Especially, the g-CN/GQDs-5 exhibited a nearly 30% improvement in TC degradation within 60 min of visible light irradiation compared to g-CN, and the kinetic constant was 1.8 times that of g-CN. The enhanced performance was attributed to the introduction of GQDs enhance the visible light absorption ability and suppress the recombination of photo-generated charges of g-CN. The capture experiment of active species showed that superoxide radicals played a major role in the degradation of TC in this system.