A binary dumbbell visible light driven photocatalyst for simultaneous hydrogen production with the selective oxidation of benzyl alcohol to benzaldehyde

Photocatalytic H₂ production with selective oxidation of organic moieties in an aqueous medium is a fascinating research area. However, the rational design of photocatalysts and their photocatalytic performance are still inadequate. In this work, we efficiently synthesized the MoS₂ tipped CdS nanowires (NWs) photocatalyst using soft templates via the two-step hydrothermal method for efficient H₂ production with selective oxidation of benzyl alcohol (BO) under visible light illumination. The optimized MoS₂ tipped CdS NWs (20 % MoS₂) photocatalyst exhibits the highest photocatalytic H₂ production efficiency of 13.55 mmol g⁻¹ h⁻¹ with 99 % selective oxidation of BO, which was 42.34 and 2.21 times greater photocatalytic performance than that of pristine CdS NWs and MoS₂/CdS NWs, respectively. The directional loading of MoS₂ at the tips of CdS NWs (as compared to nondirectional MoS₂ at CdS NWs) is the key factor towards superior H₂ production with 99 % selective oxidation of BO and has an inhibitory effect on the photo corrosion of pristine CdS NWs. Therefore, the amazing enhancement in the photocatalytic performance and selectivity of optimized MoS₂ tipped CdS NWs (20 % MoS₂) photocatalyst is due to the spatial separation of their photoexcited charge carriers through the Schottky junction. Moreover, the unique structure of the MoS₂ flower at the tip of 1D CdS NWs offers separate active sites for adsorption and surface reactions such as H₂ production at the MoS₂ flower (confirmed by Pt photo deposition) and subsequently the selective oxidation of BO at the stem of CdS NWs. This rational design of a photocatalyst could be an inspiring work for the further development of an efficient photocatalytic system for H₂ production with selective oxidation of BO (a strategy of mashing two potatoes with one fork).