Renewable biomass-derived carbon-supported g-CN doped with Ag for enhanced photocatalytic reduction of CO.

Constructing noble metal-doped g-CN/carbon composites is a feasible route to overcome the intrinsic drawbacks of pristine g-CN for enhanced activity of CO photoreduction. Herein, a novel Ag-doped g-CN/biomass-derived carbon composite with hollow bird's nest-like (Ag-g-CN/BN-C) is designed and prepared via a simple yet effective one-step pyrolysis method. In the Ag-g-CN/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-CN 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-CN/BN-C exhibits a remarkably enhanced CO evolution rate of 33.3 μmol·g·h without addition of any sacrificial reagents and photosensitizers, superior to those of both the pristine g-CN and many reported g-CN-based counterparts. The findings of this work demonstrate a good indication for integrating g-CN with SPR-dependence noble metal and renewable biomass-derived carbon for enhanced CO photoreduction, which may be extended to modify other semiconductor materials for more photocatalytic applications with enhanced activity.