Photocatalytic hydrogen evolution from biomass (glucose solution) on Au/CdS nanorods with Au3+ self-reduction

Abstract

Glucose, as one of the most familiar biomass, can be utilized to produce hydrogen and fine chemicals. This work reports the renewable hydrogen production from glucose over Au/CdS-nanorods (Au/CdS-NRs) photocatalyst. For Au/CdS-NRs catalyst, it shows a superior H2 evolution rate of 90.0 ​μmol ​g−1 ​h−1 under visible light irradiation. Moreover, the H2 generation from the glucose solution on Au/CdS-NRs prepared by twice solvothermal method is much higher than Au colloid and photoreduction methods. Prepared with twice solvothermal method, Au nanoparticles are obtained from Au3+ ions on the CdS surface, as Au3+ can be reduced by photogenerated electrons. The separated hole can oxidize glucose to produce protons, and protons can be reduced by photogenerated electrons into H2. Meanwhile, the Au/CdS-NRs can also be used to produce H2 from other biomasses, for instance sucrose, soluble starch, celluflor, pectin and waste paper scraps. The probable mechanism is proposed and discussed in the photocatalytic process from glucose reforming. This work indicates that the process of self-reducing Au3+ to Au can drastically increase the photocatalytic efficiency of H2 evolution from biomass, by promoting the separation and transportation of photogenerated charge carriers.