Elegant Construction of ZnIn2S4/BiVO4 Hierarchical Heterostructures as Direct Z-Scheme Photocatalysts for Efficient CO2 Photoreduction

The ZnIn 2 S 4 /BiVO 4 heterostructures were elegantly designed through assembling ZnIn 2 S 4 nanosheets onto the surface of BiVO 4 decahedrons. This composite photocatalyst exhibits efficient photocatalytic conversion of CO 2 into CO with a detectable amount of CH 4 in the presence of water vapor. An electron spin-resonance spectroscopy (ESR) technique and density function theory (DFT) calculation affirm the direct Z-scheme structure in ZnIn 2 S 4 /BiVO 4 . The larger surface photovoltage (SPV) change and the longer liquid photoluminescence (PL) lifetime of the heterostructure, compared to the individual ZnIn 2 S 4 and BiVO 4 components, demonstrate that the Z-scheme structure can effectively promote the recombination of the photogenerated holes in the valence band (VB) of the ZnIn 2 S 4 nanosheet with the electrons in the conduction band (CB) of the decahedral BiVO 4 and lead to the abundant electrons surviving in the CB of ZnIn 2 S 4 and holes in the VB of BiVO 4, thus enhancing photocatalytic CO 2 reduction performance. This study may make a potential contribution to the rational construction and deep understanding of the underlying mechanism of direct Z-schemes for advanced photocatalytic activity.