Insights into Selective Glucose Photoreforming for Coproduction of Hydrogen and Organic Acid over Biochar-Based Heterojunction Photocatalyst Cadmium Sulfide/Titania/Biochar

Abstract

Biomass photorefinery over a sustainable biochar (BC)-based heterojunction provides a promising approach to alleviate the worsening environment and energy crisis via sustainable hydrogen (H2) and valuable chemicals production. Moreover, no related results have been reported. Here, a novel BC-supported CdS/TiO2 photocatalyst (CdS/TiO2/BC) was rationally fabricated by simple hydrothermal and calcination methods for glucose photoreforming. The selectivity of value-added chemicals was modulated by alteration of the base type. BC, with large specific surface area and outstanding electrical conductivity, was employed as the carrier of the CdS/TiO2 heterojunction, which further facilitated the light absorption and charge separation. The as-synthesized CdS/TiO2/BC exhibited excellent acetic acid selectivity (63.94%) together with improved H2 generation (∼12.77 mmol g−1 h−1) in 25 mM NaOH solution, while efficient formic acid selectivity (60.29%) and H2 generation (∼10.29 mmol g−1 h−1) were observed in 3 mM Na2CO3 solution. Trapping tests indicated that ·O2− and ·OH promoted the production of acetic acid. This study initiates a novel insight into the design of environmentally friendly photocatalysts for fuel and chemicals production from biomass photorefinery.