Surface structure modulation of biochar enables high-efficiency photodriven CO2 fixation

Reforming desirable photocatalytic platforms for efficient carbon dioxide (CO 2 ) utilization is highly desirable but represents a great challenge. In this study, we report a facile surface structure modulation strategy to fabricate functional biochars (BCs) with different surface oxygen functional groups. The mild oxidation of sodium hypochlorite endows BC with abundant surface oxygen species without significantly compromising its inherent morphology. Under Xe lamp irradiation (400 mW/cm 2 ) and 1 bar CO 2 , the catalytic activity toward the coupling of CO 2 and epichlorohydrin based on BC-NaClO reached 100% yield, which was 3.8, 2.6, and 1.5 times greater than that of pristine BC, functional BC-HNO 3 , and BC-NaOH, respectively. Further investigations revealed the contributions of both holes and electrons to the photocatalytic activity of BC-NaClO and the synergistic effects of photocatalysis and photothermal catalysis. This work demonstrates a rational pathway toward high-efficiency biomass-derived photocatalysts for targeted CO 2 conversion.