Electrocatalytic CO2 Reduction via a Permeable CNT Hollow-Fiber Electrode Incorporated with SnO2 Nanoparticles

Abstract

Herein, we introduce a permeable carbon nanotube hollow-fiber electrode incorporated with SnO2nanoparticles (SnO2-CHE) and propose a new type of gas-phase operational mode. Highly efficient electrochemical syngas production from CO2is made possible by switching the operating mode from liquid phase to gas phase. The operation of SnO2-CHE in the conventional liquid-phase mode yielded a H2/CO ratio higher than 4.59, and the maximum jCOwas only 2.16 mA/cm2 at-0.88 V (vs RHE) due to the low solubility and limited mass transfer of CO2in liquid electrolytes. On the other hand, SnO2-CHE operated under the newly designed gas-phase mode achieved a H2/CO ratio ranging from 1.22 to 4.11 with a maximum jCOof 7.42 mA/cm2 at-0.76 V (vs RHE), which is proper for direct post-conversion processes. Therefore, this work could offer a new avenue for electrochemical syngas production using a nonprecious metal-based hollow-fiber type electrode, which allows for a large electrode surface area and high CO2availability in gas-phase operation.