Synergism between nitrogen vacancies and a unique electrons transfer pathway of Ag modified S-scheme g-C₃N₄/CdS heterojunction for efficient H₂ evolution

Ag modified g-C₃N₄/CdS (Ag@g-C₃N₄/CdS) S-scheme heterojunction with a distinctive charge transfer channel was prepared as a photocatalyst for photoreduction of H₂O. The effect of nitrogen vacancies and photo-excited charge carriers in the water splitting on the Ag@g-C₃N₄/CdS was discussed. It was found that the charge carriers transport channel in Ag@g-C3N4/CdS S-scheme heterojunction was instrumental in the enhancement of H₂ production. The electrons in Ag nanospheres and in the conduction band (CB) of CdS can recombine with the holes in the valence band (VB) of g-C₃N₄, which prolonged the lifetime of electrons in the CB of g-C₃N₄. Meanwhile, a unique charge transfer channel was produced in the Ag@g-C₃N₄/CdS. Compared with g-C₃N₄, Ag@g-C₃N₄/CdS photocatalyst demonstrated an enhanced performance which was assigned to the increased charge carrier lifetime. The supreme Ag@g-C₃N₄/CdS showed photocatalytic H₂ production activity up to 204.19 μmol for 4 h under illuminate (λ ≥ 420 nm), which was 11.74 times than that of g-C₃N₄.