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

A binary dumbbell MoS 2 tipped CdS NWs visible light driven photocatalytic system was successfully prepared using soft templates via the two-step hydrothermal method. The optimized MoS 2 tipped CdS NWs (20% MoS 2) photocatalyst exhibits the highest photocatalytic H 2 production efficiency of 13.55 mmol g-1h−1 with 99% selective oxidation of BO. The unique structure of MoS 2 flower at the tip of 1D CdS NWs offers separate active sites for adsorption and surface reactions such as H 2 production at the MoS 2 flower and subsequently the selective oxidation of BO at the stem of CdS NWs. Therefore, the amazing enhancement in the photocatalytic performance and selectivity of optimized MoS 2 tipped CdS NWs (20% MoS 2) photocatalyst is due to the spatial separation of their photoexcited charge carriers through the Schottky junction. [Display omitted] Photocatalytic H 2 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 MoS 2 tipped CdS nanowires (NWs) photocatalyst using soft templates via the two-step hydrothermal method for efficient H 2 production with selective oxidation of benzyl alcohol (BO) under visible light illumination. The optimized MoS 2 tipped CdS NWs (20 % MoS 2) photocatalyst exhibits the highest photocatalytic H 2 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 MoS 2 /CdS NWs, respectively. The directional loading of MoS 2 at the tips of CdS NWs (as compared to nondirectional MoS 2 at CdS NWs) is the key factor towards superior H 2 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 MoS 2 tipped CdS NWs (20 % MoS 2) photocatalyst is due to the spatial separation of their photoexcited charge carriers through the Schottky junction. Moreover, the unique structure of the MoS 2 flower at the tip of 1D CdS NWs offers separate active sites for adsorption and surface reactions such as H 2 production at the MoS 2 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 H 2 production with selective oxidation of BO (a strategy of mashing two potatoes with one fork). [ABSTRACT FROM AUTHOR]