Direct conversion of rice husks to nanostructured SiC/C for CO2 photoreduction

Abstract

A one-step and template-free synthesis of a SiC nanowires/C (SiC-NW/C) composite from rice husks (RHs) is realized via a molten-salt-assisted electrochemical method. The process integrates simultaneously carbonization, electrodeoxidation, nanostructuring, and self-purification for converting RHs to a SiC-NW/C hybrid that is assembled from SiC NWs embedded in porous N-doped graphitic carbon with strong coupling. The SiC-NW/C nanostructure enables efficient CO2 adsorption and fast separation and transfer of charge carriers. Benefiting from the structural and compositional merits, the SiC-NW/C composite shows superior activity for photoreduction of CO2 to CO, in the absence of any additional cocatalysts or sacrificial agents. The process proposed herein might help to bridge a closed-loop carbon cycle in the whole production-utilization of biomass.