Photo-electrocatalytic synthesis of 2,5-furan dicarboxylic acid and hydrogen co-production from straw-based microcrystalline cellulose by a CdS/TiO2-graphene composite catalyst

The low photocatalytic efficiency and complex composition of corn stover biomass have always been the bottlenecks restricting the development of photocatalytic biomass conversion in 2,5-furandicarboxylic acid technology. Most photocatalysts have low conversion efficiency and low selectivity in the oxidation of straw, and their conversion rate to the desired products cannot be guaranteed. Therefore, efficient composite photocatalysts of CdS/TiO2 and corn stover-based graphene were prepared using corn stover-derived graphene structures. The materials were applied in the catalytic oxidation of 5-hydroxymethylfurfural (HMF) from corn stover-derived microcrystalline cellulose and the one-step photocatalytic conversion to 2,5-furandicarboxylic acid (FDCA), while synergistically producing hydrogen. The experimental results of the photocatalytic reaction revealed possible reaction pathways, and theoretical calculations further confirmed that hydroxyl oxidation is a rate-determining step in the process. With the optimal component ratio, the conversion rate of HMF reached 100% with an FDCA yield of 99.4%. The Faraday efficiency of hydrogen production was 96%, indicating good synergistic photocatalytic performance. This study provides new ideas for the conversion of biomass waste into FDCA.