Renewable biomass-derived carbon-supported g-C3N4 doped with Ag for enhanced photocatalytic reduction of CO2

Constructing noble metal-doped g-C 3 N 4 /carbon composites is a feasible route to overcome the intrinsic drawbacks of pristine g-C 3 N 4 for enhanced activity of CO 2 photoreduction. Herein, a novel Ag-doped g-C 3 N 4 /biomass-derived carbon composite with hollow bird's nest-like (Ag-g-C 3 N 4 /BN-C) is designed and prepared via a simple yet effective one-step pyrolysis method. In the Ag-g-C 3 N 4 /BN-C, the highly-dispersed Ag nanoparticles (20–30 nm) with the surface plasmon resonance (SPR) effect act as a significant cocatalyst not only to efficiently trap the photogenerated electrons from g-C 3 N 4 to boost the separation of photogenerated electron-hole pairs but also to produce additional active “hot electrons”, while the conductive quasi-spherical hollow structure of BN-C doubles the specific surface area with multiple reflections of light, providing abundant active sites and more utilization efficiency of light energy. As a result, the Ag-g-C 3 N 4 /BN-C exhibits a remarkably enhanced CO evolution rate of 33.3 μmol·g −1 ·h −1 without addition of any sacrificial reagents and photosensitizers, superior to those of both the pristine g-C 3 N 4 and many reported g-C 3 N 4 -based counterparts. The findings of this work demonstrate a good indication for integrating g-C 3 N 4 with SPR-dependence noble metal and renewable biomass-derived carbon for enhanced CO 2 photoreduction, which may be extended to modify other semiconductor materials for more photocatalytic applications with enhanced activity.