In-situ carbon-doped poly(triazine imide) modified with silver nanoparticles for synergistic efficient photocatalytic CO2 reduction coupled with biomass refining

In-situ carbon-doped poly(triazine imide) modified with silver nanoparticles for synergistic efficient photocatalytic CO2 reduction coupled with biomass refining. [Display omitted] •In-situ carbon-doped poly(triazine imide) with Ag nanoparticles was designed.•Photocatalytic CO2 reduction and biorefinery were achieved simultaneously.•CO evolution rate over Ag/C@PTI is 3.29 times higher than pure PTI.•A high xylonic acid yield of 51.4 % was obtained over Ag/C@PTI. Solar-driven CO2 reduction to fuels holds critical importance in addressing climate and energy challenges. However, the practical application faces limitations due to the difficulty in activating CO2, the slow kinetics of the oxidation half-reaction, and the generation of undesired by-products. Herein, we report a functionally-oriented approach for the deliberate fabrication of in-situ carbon-doped poly(triazine imide) modified with silver nanoparticles (Ag NPs) (Ag/C@PTI), aimed at solar-driven CO2 reduction synchronized with xylose oxidation within a single redox cycle. The strategic in-situ carbon doping and the deposition of Ag NPs significantly reduce the bandgap of PTI to 1.60 eV, thereby markedly enhancing charge carrier separation and refining product selectivity. Consequently, the optimally formulated Ag10/C@PTI-10 catalyst demonstrates superior photocatalytic performance in xylose oxidation coupled with CO2 reduction, achieving a xylonic acid yield of 51.4 % and a CO evolution rate of 31.4 μmol g-1h-1. The 13CO2 isotope labeling experiments confirm that a portion of the CO is derived from the xylose conversion process. Moreover, ESR characterization along with capture tests reveal that h+ and ·O2- are pivotal in the photooxidation of xylose to xylonic acid.