Z-scheme based fabrication of Cu2CdSnS4/Au/g-C3N4 ternary heterojunction with enhanced photocatalytic hydrogen production

Abstract

Using the photo-deposition-hydrothermal approach, we synthesized a new Z-scheme Cu₂CdSnS₄/Au/g-C₃N₄ ternary heterojunction with varying levels of Au. This was done to improve the photocatalytic performance of the material. Due to rapid electron-hole recombination and insufficient solar light absorption, Cu₂CdSnS₄/Au/g-C₃N₄ struggles to achieve its maximum photocatalytic activity. Cu₂CdSnS₄/Au/g-C₃N₄ heterojunction photocatalysts, which are composed of nanosheets of Au/g-C₃N₄ and Cu₂CdSnS₄, have recently been studied by employing several techniques. These hybrid photocatalysts are characterized by their heterojunction properties. A variety of methods may be utilized, including SEM, XRD, FT-IR, XPS, TEM, and UV–Vis. After 3 h under visible light irradiation, it was discovered that the final composite Cu₂CdSnS₄/Au/g-C₃N₄ heterojunction generated 2478.6 μmol g⁻¹ hydrogen. This result was 14 times greater than the pristine g-C₃N₄ heterojunction and 4.5 times greater than the pristine Cu₂CdSnS₄ heterojunction. On the other hand, the sacrificial electron donors triethanolamine (TEOA) and methanol exhibited extended photostability, with hydrogen production rates of 2478.6 μmol g⁻¹ and 330.7 μmol g⁻¹, respectively, compared to glycerol, which yielded a hydrogen production rate of 2105.7 μmol g⁻¹. After conducting an in-depth investigation of heterojunction photocatalysts, we found that Cu₂CdSnS₄ is highly effective in photon harvesting. This efficiency is attributed to the selective utilization of Z-scheme charge transfer, enabled by multiple charge transfer pathways. This study confirmed that heterojunction photocatalysts exhibit outstanding photocatalytic performance for hydrogen production.