Concurrent photocatalytic bicarbonate (aqueous-CO₂) reduction and xylose reforming to produce compounds from C—C coupling

Using CO₂ (or aqueous-CO₂, HCO₃⁻) and biomass as feedstock to produce chemicals under solar irradiation represents a promising approach to achieving the net-zero emission goal. In this study, we employed a highly efficient ^•H-forming photocatalyst to convert HCO₃⁻, demonstrating the occurrence of C[sbnd]C coupling to produce C₂-species. Under simulated solar illumination, the photocatalytic system consistently reduces HCO₃⁻ into acetate through the coupling of ^•CO₂⁻ radicals. Additionally, in the photoreforming of xylose, acetate emerges as the predominant product, likely resulting from the coupling of ^•CO₂⁻ derived from the interaction of formate and ^•OH. Notably, a C₆-compound is generated through C[sbnd]C coupling of radicals originating from HCO₃⁻ and xylose. Achieving an overall apparent quantum efficiency of 26% under 420-nm irradiation, our work underscores the feasibility of concurrently photocatalyzing the conversion of CO₂ and biomass into chemicals through C[sbnd]C coupling. This study not only highlights the significance of our approach in contributing to the net-zero emission goal but also emphasizes the novelty of achieving concurrent photocatalytic conversion.