Fabrication of g-C3N4/Au/CdZnS Z-scheme photocatalyst to enhance photocatalysis performance

In this study, a sandwich-structured C3N4/Au/CdZnS photocatalyst with Au nanoparticles sandwiched between C3N4 and CdZnS was fabricated. The results showed that there was a 6.3 mmol g−1 increase of hydrogen production for C3N4/Au/CdZnS photocatalyst compared to C3N4/CdZnS in 4 h. The photoinduced I–t curve, electrochemical impedance spectrum (EIS), photogenerated electron lifetime and photoluminescence spectra showed that the photocatalytic ability of the composite was enhanced by anchoring Au as the electron transfer mediator between C3N4 and CdZnS through the Z-scheme charge-carrier transfer mechanism. Au functioned as an electron transition mediator, which could induce a combination between photogenerated electrons and holes in the CdZnS and C3N4, respectively. These photogenerated holes of CdZnS can be involved in the S2−/SO32− oxidation process and the electrons from the C3N4 surface might be involved in the water to hydrogen reduction reaction, thus enhancing the photocatalysis performance of C3N4/Au/CdZnS photocatalyst.