Sulfur vacancy and CdS phase transition synergistically boosting one-dimensional CdS/Cu2S/SiO2 hollow tube for photocatalytic hydrogen evolution

Constructing an efficient photoelectron transfer route to improve carrier separation efficiency is crucial for photocatalytic hydrogen evolution. In this work, CdS/Cu2S/SiO2 heterostructure with one-dimensional hollow tube morphology was designed by the solvothermal method using CuO/SiO2 hollow tube as carrier. The hexagonal phase CdS and sulfur vacancies were adjusted simultaneously by the reduction strategy of NaBH4 aqueous solution. CdS/CuS/SiO2 with cubic phase CdS was synthesized in the absence of NaBH4 aqueous solution. CdS/Cu2S/SiO2 was characterized by SEM, TEM, XRD, XPS, SPV and so on. The results showed that hexagonal CdS and sulfur vacancies benefited the separation of photo-generated carriers. As a consequence, the CdS/Cu2S/SiO2-10 composite exhibited a high photocatalytic hydrogen production rate (1196.98 μmol/g/h), and its performance almost 7.18 times than that of CdS/CuS/SiO2. Moreover, CdS/Cu2S/SiO2-10 showed an excellent cyclic stability. This was attributed to the strong electron interaction of CdS/Cu2S/SiO2 heterostructure and the sulfur vacancy acted as an electron trap, enhancing the separation of photo-induced electrons and holes.