Improvement of charge-transfer kinetics via MXene and cobalt containing polyoxometalate loading on CdS for photocatalytic hydrogen production

Hydrogen is a renewable and clean energy, and photocatalytic water splitting for hydrogen evolution technology is a promising technical means to solve the development problem. In this study, the ternary composite Co₈POM@MXene-CdS hybrid catalyst was constructed and used for photocatalytic hydrogen production. Under the condition of AM 1.5G simulated sunlight, the photocatalytic H₂ evolution rate of the ternary composite was 8.13 mmol g⁻¹ h⁻¹, which was more than 25 times higher than that of the bare CdS. By means of synchronous illumination X-ray photoelectron spectroscopy (SI-XPS) and density functional theory (DFT) calculations, it was proved that the loading of MXene and Co₈POM improved the photogenerated carrier separation and immigration efficiency on CdS. The photogenerated electrons transfer from CdS to MXene. Co₈POM containing the {Co₄O₃} quasi-cubane, as an oxidation co-catalyst, accepts photogenerated holes from CdS to catalyze the oxidation reaction of TEOA, which improves the photocatalytic hydrogen production activity and the stability of CdS.