Cobalt oxide coupled with graphitic carbon nitride composite heterojunction for efficient Z-scheme photocatalytic environmental pollutants degradation performance

The Co3O4/g-C3N4 Z-scheme composite heterojunction has been effectively built in a facile sonication-assisted hydrothermal manner. The as-synthesized optimal 0.2 M Co3O4/g-C3N4 (GCO2) composite photocatalysts (PCs) revealed admirable degradation efficiency towards methyl orange (MO, 65.1%) and methylene blue (MB, 87.9%) organic pollutant compared with bare g-C3N4 within 210 min under light irradiation. Besides, the features of investigating structural, morphological and optical properties have evidence that the unique decoration effect of Co3O4 nanoparticles (NPs) on the g-C3N4 structure with intimate interface heterojunction of well-matched band structures noticeably facilitates the photo-generated charge transport/separation efficiency, reduces the recombination rates and widens the visible-light fascination which could advantageous to upgrading photocatalytic action with superior redox ability. Especially, the probable Z-scheme photocatalytic mechanism pathway is also elucidated in detail based on the quenching results. Hence, this work delivers a facile and hopeful candidate for contaminated water remediation via visible-light photocatalysis over the efficient g–C3N4–based catalysts. •A novel photocatalyst Co3O4/g-C3N4 was synthesized by a facile way.•0.2 M Co3O4/g-C3N4 PCs shows superior catalytic degradation activity for both dye.•The improved photocatalytic activity owing to the efficient Z-scheme systems.•A possible photocatalytic mechanism of the Co3O4/g-C3N4 has been inspected in depth.