Interface design for enhancing carbon dioxide electrolysis in a fluidized electrode of photoelectrochemical cell

Abstract

Excessive emission of CO2 has threatened the global climate and human health. Electrolysis offers a promising avenue to convert CO2 into valuable fuels such as methane. However, the electrolysis of CO2 often limited by a long diffusion pathway and high mass transfer resistance from electrolyte to the surface of catalysts. In this paper, we propose a bubbling fluidized electrode with catalyst/ionomer interface design, allowing an efficient gas transport and a high local CO2 concentration near the surface of catalysts. By applying above design strategy, the bubbling fluidized electrode exhibits a remarkably decreased diffusion length of CO2 as low as several nanometers and delivers a high selectivity with a faradic efficiency of ∼100 % at −0.4 V vs RHE. The universality of the interface design is further verified by using different hydrophobic materials, achieving a remarkably improved performance. In the actual application, a photoelectrochemical cell equipped with the bubbling fluidized electrode shows a high stability with a FE > 90 %. These results demonstrate a viable strategy to facilitate the electrolysis process involving gas-electrolyte-solid phase reactions (e.g., CO2 reduction reaction) through a bubbling fluidized electrode with catalyst/ionomer interface design.