Enhanced photocatalytic CO2 reduction activity of MOF-derived ZnO/NiO porous hollow spheres

The conversion of CO2 into clean energy by exploiting porous hollow structure photocatalysts with superior activity is of worldwide interest. In this work, ZnO/NiO porous hollow spheres with sheet-like subunits were obtained by calcination of the Ni-Zn bimetallic organic frameworks (MOFs). The prepared ZnO/NiO composites exhibited enhanced photocatalytic activity for CO2 recondition, and the highest CH3OH evolution rate was observed for sample ZN-30, which was about 3 times than that of pure ZnO. It is believed that the heterogeneous n-type ZnO and p-type NiO produced from the decomposition of heterothallic Zn-Ni MOFs are homogeneously mixed together, resulting in the formation of many p-n heterojunctions which could be benefit to the charge separation. Furthermore, such porous hollow structure could increase the specific surface area, CO2 uptake capacity as well as the light absorption property. Thus, the composite photocatalyst exhibited excellent photocatalytic CO2 reduction performance. This work provides a new insight to finely design and fabricate novel heterogeneous composite with hollow structure in photocatalysis by using multi-metallic organic frameworks as the precursors.