A novel preparation of GaN-ZnO/g-C3N4 photocatalyst for methylene blue degradation

[Display omitted] •GaN-ZnO/g-C3N4 composite was prepared.•Photocatalytic performance was investigated.•g-C3N4 improves photocatalytic performance for the composite. GaN-ZnO solid solution (labeled as GN-ZO) was prepared by a novel method using melamine as a nitrogen source and then GaN-ZnO/g-C3N4 composite (denoted as GN-ZO/CN) was synthesized by the polymerization of melamine in the presence of GN-ZO. The photodegradation of methylene blue (MB) on GN-ZO/CN was assessed, which shows that the degradation efficiency of MB over GN-ZO/CN reaches up to 98.1% after 5 h. This is due to a reduced recombination of photogenerated electrons and holes in the composite. The photocatalytic activity of GN-ZO/CN is stable after 4 cycles. The mechanism for photocatalytic degradation of MB on GN-ZO/CN is proposed.