The role of facet engineered surface and interface in CdS nanostructures toward solar driven hydrogen evolution

Crystal facet of materials is an important parameter that affects the catalytic properties of photocatalysts. In this study, taking CdS as a prototype, we demonstrate the different role of facet as surface active site and interfacial charge migration channel. CdS nanorods exposed with {100} facet and CdS nanosheets exposed with {0 0 1} facet can be synthesized via simple wet chemical methods. In photocatalytic reaction, experimental results demonstrate that pristine CdS nanorods show higher hydrogen evolution rate (16.99 mu mol/h) than that of pristine CdS nanosheets (4.97 mu mol/h). As a contrast, when integrating with Pt cocatalyst forming Pt-CdS hy-brids, the loading of Pt can improve the hydrogen evolution rate of CdS nanorods by 9.99-folds, significantly lower than CdS nanosheets (26.41-folds). In the case of using pristine CdS as catalysts, {1 0 0} facet is more beneficial for proton adsorption compared to {001} facet, leading to higher performance of CdS nanorods exposed with {1 0 0} facet as surface reaction sites. As for Pt/CdS catalysts, photogenerated electrons can more effectively transfer across the CdS {0 0 1}-Pt interface than that of CdS {10 0}-Pt interface, resulting in higher enhancement factors of CdS nanosheets after loading of Pt cocatalysts. These results may provide ideas for designing photocatalysts based on facet engineering.

Automated summary

This study synthesized CdS nanorods and CdS nanosheets with exposed {100} and {0 0 1} facets respectively, and demonstrated the different roles of different facets in photocatalytic performance. It was found that pristine CdS nanorods showed higher hydrogen evolution rate than CdS nanosheets. However, when integrated with Pt cocatalyst, the enhancement in hydrogen evolution rate was significantly lower for CdS nanorods compared to CdS nanosheets. The adsorption of protons and interfacial charge migration played important roles in determining the performance of CdS nanorods and nanosheets.