ZIF-67-Derived 3D Hollow Mesoporous Crystalline Co3O4 Wrapped by 2D g-C3N4 Nanosheets for Photocatalytic Removal of Nitric Oxide

ZIF-67-derived 3D hollow mesoporous crystalline Co3O4 wrapped by 2D graphitic carbon nitride (g-C3N4) nanosheets are prepared by low temperature annealing, and are used for the photocatalytic oxidation of nitric oxide (NO) at a concentration of 600 ppb. The p-n heterojunction between Co3O4 and g-C3N4 forms a spatial conductive network frame and results in a broad visible light response range. The hollow mesoporous structure of Co3O4 contributes to the circulation and adsorption of NO, and the large specific surface area exposes abundant active sites for the reaction of active species. A maximum NO degradation efficiency of 57% is achieved by adjusting the mass of the Co3O4 precursor. Cycling tests and X-ray diffraction indicate the high stability and recyclability of the composite, making it promising in environmental purification applications.