Achieving high hydrogen production of MWCNTs-CdS photocatalyst through microstructure regulation

The photocatalytic material CdS has the advantages of a narrow energy gap and a suitable conduction band potential, but the rapid compounding of photogenerated carriers limits its large-scale application. To overcome these drawbacks, MWCNTs-CdS composites were prepared in this work and the thermodynamic and kinetic behaviour during the hydrothermal growth of MWCNTs-CdS was investigated. On this basis, the microscopic morphology of MWCNTs-CdS was regulated by designing the ratio of oleic acid and oleylamine, which in turn improved the photocatalytic hydrogen production efficiency of MWCNTs-CdS. The results showed that MWCNTs effectively improved the photogenerated carrier utilisation efficiency of CdS, and with the prolongation of hydrothermal time and the increase of temperature, the crystallinity of CdS increased and the photogenerated electron-hole complexation rate decreased. In addition, the introduction of oleic acid and oleylamine led to a decrease in the particle size and an increase in the specific surface area of MWCNTs-CdS, which in turn enhanced the photocatalytic performance. Under the light condition, the hydrogen production rate of MWCNTs-CdS(OAc:OAm=0.5:1.5) reached 189.10 μmol/g/h, which was 13.30 times higher than that of pure CdS.