CuInS2 quantum dots anchored onto the three-dimensional flexible self-supporting graphene oxide array with regulatable crystallinity and defect density for efficient photocatalytic synthesis of xylonic acid

Photocatalytic biorefinery is receiving increasing attention as a promising approach for biomass utilization. In this field, I-III-VI quantum dots have emerged as efficient photocatalysts with unique physical and chemical properties that stem from their quantum and size effects. To fully exploit the advantages of quantum dots, a three-dimensional flexible self-supporting material (CIS@FSM) is fabricated with the assistance of defect-rich graphene oxide (GO), which is employed as a supporter to trap the quantum dots and promote charge separation/migration. Under visible-light irradiation, a xylonic acid yield of 65.05 % is obtained and no obvious decline of the photocatalytic performance is observed after nine runs. Moreover, the photocatalytic performance of CIS@FSM can be tuned by modulating the crystallinity and defect density. The investigation of the mechanism of the xylonic acid production reveals the presence of all oxidation active species, with h + playing the primary role. This work provides insights for semiconductor-based photocatalytic biorefinery. CuInS 2 quantum dots anchored onto the three-dimensional flexible self-supporting graphene oxide array with regulatable crystallinity and defect density for efficient photocatalytic synthesis of xylonic acid. • A novel flexible 3D self-supporting material was prepared by a facile method. • Quantum effect of CuInS 2 quantum dots led to good electrical properties. • GO and annealing led to more efficient light absorption at NIR. • Crystallinity and defect density were easily modulated for good catalytic activity.