Simultaneous hydrogen production with the selective oxidation of benzyl alcohol to benzaldehyde by a noble-metal-free photocatalyst VC/CdS nanowires

In this work we used CdS NWs (nanowires) with vanadium carbide (VC) attached via facile electrostatic self-assembly and calcination method. The results showed that compared to pristine CdS NWs, the photocatalytic activity of CdS NWs loaded with the particular amount of VC was dramatically enhanced. Among them, the VC/CS-15 indicated the highest enhancement for simultaneous production of H2 with selective oxidation of benzyl alcohol (BO) into benzaldehyde (BD). The highest hydrogen evolution rate of 20.5 mmol g(-1) h(-1) was obtained with more than 99% selectivity for BD production under visible light (lambda > 420 nm) irradiation for 2 h, which was almost 661 times higher than the pristine CdS NWs. This enhancement of photocatalytic activity is due to the VC, which provides a favorable attraction for BO by lowering the zeta potential, along with the active site for hydrogen production, and retard the recombination of electron-hole pairs by increasing the conductivity of the photocatalyst. Moreover, the apparent quantum efficiency (AQE) of VC/CS-15 for BD and H-2 production at monochromatic 420 nm is about 7.5%. At the end of the hydrogen evolution test, the selective oxidation with more than 99% selectivity was obtained. It hopes this work will prove its future significance and move scientific community toward a more economical way for achieving the commercialization of H-2 by photocatalysis. (C) 2022, Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved.

Automated summary

In this study, CdS nanowires were combined with vanadium carbide using a specific method, and it was found that the photocatalytic activity of the CdS nanowires was significantly enhanced when loaded with vanadium carbide, especially for simultaneous production of H2 and selective oxidation of benzyl alcohol into benzaldehyde. Additionally, the vanadium carbide loading also reduced the recombination rate of hydrogen and benzaldehyde. The results of this study demonstrate the importance of this method in achieving commercialization of photocatalytic hydrogen production.