Engineering efficient Self-Supporting SnO2/Carbon nanofiber electrode for electrochemical CO2 reduction

Electrochemical CO 2 reduction (ECR) to value-added products provides a pathway to reduce CO 2 emission and to enable a closed carbon cycle. Compared to powdered catalysts, self-supporting electrocatalysts have more prominent advantages such as high charge transfer capacity and the ability to serve directly as working electrodes without the need for binders. Herein, a self-supporting catalyst featuring SnO 2 nanoparticles incorporated into porous carbon nanofiber (SnO 2 -PCNF) was crafted via electrospinning followed by annealing in CO 2 . SnO 2 -PCNF can directly function as working electrode for ECR to produce HCOOH, achieving a high Faradaic efficiency of 92.3%. Also, the SnO 2 -PCNF can stably catalyze ECR process for more than 50 h. Theoretical calculations and in-situ Raman spectroscopy elucidate the underlying ECR mechanism over SnO 2 -PCNF, wherein the catalyst significantly reduces the energy barrier of the rate-determining step. This effectively suppresses the competitive hydrogen generation. This work provides some insights into design of binder-free and high-performance ECR electrocatalysts.