Photocatalytic degradable polymer precursor production and C–C bond synthesis with CO2 over sulfur vacancies enriched ZnIn2S4 nanosheets

Degradable polymer precursor FDCA could be easily produced through efficient furfural in situ oxidation, furan ring SP 2 C–H activation as well as CO 2 reduction over photocatalyst ZnIn 2 S 4 in green solvent H 2 O. Different aromatic hydrocarbons and olefins could also be converted to carboxylation product with excellent yield under 1 atm CO 2 . On the other hand, the ZnIn 2 S 4 nanosheets, with reduced thickness along with improved photogenerated charge transfer efficiency, obviously improved the photocatalytic carboxylation efficiency. When S vacancies were introduced into ZnIn 2 S 4 nanosheets, the photocatalytic carboxylation efficiency was further improved. • FDCA was easily produced through furfural in situ oxidation and CO 2 reduction without sacrificial agent. • Furan ring SP 2 C–H activation was achieved firstly under mild conditions in the photocatalytic carboxylation. • Charge transfer promoted ZnIn 2 S 4 nanosheets obviously enhanced the photocatalytic carboxylation efficiency. • Photogenerated electrons enriched S vacancies modified ZnIn 2 S 4 nanosheets further improved the carboxylation. • Different aromatic hydrocarbons and olefins could be converted to carboxylation products with 1 atm CO 2 . It is of significant importance, promise and challenge to combine the waste carbon resource CO 2 transformation and the renewable biomass utilization in highly value-added chemical intermediates preparation. In this work, degradable polymer precursor 2,5-furandicarboxylic acid (FDCA) could be easily produced through efficient furfural in situ oxidation, furan ring sp 2 C–H activation as well as CO 2 reduction over photocatalyst ZnIn 2 S 4 in green solvent H 2 O. It is worth mentioning that furan ring sp 2 C–H activation could be achieved under rather mild conditions, and no sacrificial agent was needed during the photocatalytic carboxylation process to produce FDCA. Different aromatic hydrocarbons and olefins could also be converted to carboxylation products with excellent yield under 1 atm CO 2 . On the other side, the ZnIn 2 S 4 nanosheets, which had reduced thickness along with improved photogenerated charge transfer efficiency, obviously improved the photocatalytic carboxylation efficiency. When S vacancies were introduced into ZnIn 2 S 4 nanosheets, the photocatalytic carboxylation efficiency improvement was ascribed to the photogenerated electrons enrichment and substrates capture ability enhancement.