fig6

Figure 6. (A) MS curves and (B) Tauc plot of VZn-ZIS; (C) In-situ FTIR spectra of UCNPs@VZn-ZIS; (D) Photocatalytic CO2 reduction mechanism on UCNPs@VZn-ZIS under the NIR light irradiation. MS: Mott-Schottky; VZn-ZIS: Zn vacancy-rich ZnIn2S4; in-situ FTIR: in-situ Fourier transform infrared; UCNPs: up-conversion nanoparticles; NIR: near-infrared.