Solar-light-driven photocatalytic degradation of methyl orange dye over Co3O4-ZnO nanoparticles

•Coexistence of ZnO and Co3O4 in Co3O4-ZnO nanoparticle from the bi metal-organic framework.•The formation of p-n nano-heterojunctions and the transition of electrons from Co3O4 to ZnO.•Entire degradation of MO by Co3O4-ZnO NPs for 120 min under solar light.•Significant stability and recyclability for four catalytic cycles of Co3O4-ZnO NPs. Herein, we prepared the in-situ CoZn-Metal-Organic Framework (MOF) nanoparticles (NPs) and converted them into bi-oxide metal Co3O4-ZnO nano-size by calcination. Under solar light, both Co3O4 and ZnO are excited about having electrons and holes. The photogenerated electrons passed from the conductive Co3O4 band to the ZnO band, react to adsorbed oxygen molecules and water to produce superoxide radical anions like ·O2−, and OH−. In the meantime, H2O and OH− trap the exciting holes on to yield OH−, and OH species and entirely degraded methyl orange (MO) under solar light after 120 min. Co3O4-ZnO NPs photocatalyst displayed significant stability and recyclability for four catalytic cycles.