Engineering of hierarchical Z-scheme ZnSe/Fe2O3 heterojunction cubic nanocages for enhanced CO2 to CO photoconversion

Abstract

The photocatalytic conversion of CO₂ into fuels is a promising strategy for achieving global carbon neutrality. However, the weak redox reaction ability and fast charge recombination rate of a single component catalyst remain a huge bottleneck. To overcome these disadvantages, herein, hierarchical Z-scheme ZnSe/Fe₂O₃ heterojunction hollow cubic nanocages were designed and prepared using Fe₂O₃ cubic nanocages (CNCs) derived through the straightforward thermal annealing of the FeOOH CNCs synthesized based on Pearson's principle using Cu₂O as a sacrificial template and the subsequent immobilization of ZnSe nanoparticles derived from the selenization of the ZIF-8 nanolayer on the Fe₂O₃ CNCs. The experimental characterization studies reveal that the Z-scheme ZnSe/Fe₂O₃ heterojunction cubic nanocage structure promotes efficient charge separation/transfer and preserves the reduction and oxidation abilities of the composites. These advantages make the optimized Z-scheme ZnSe/Fe₂O₃ CNC composite exhibit an excellent CO₂ photoreduction performance compared to pristine ZnSe with a CO yield of 28.1 μmol g⁻¹ h⁻¹. This work provides a new perspective on constructing photocatalyst systems with Z-scheme heterojunctions to enhance photocatalytic performance.