Efficient Photocatalytic Degradation of Potent Greenhouse Gas Sf6 at Liquid-Solid Interface

Abstract

Sulfur hexafluoride (SF6), widely used in industries, poses a significant threat as the strongest greenhouse gas. Current methods for degrading SF6 are hindered by high energy consumption and costs, thus there is an urgent need for a low-cost, convenient, and efficient solution. In response, we established a gas-liquid-solid three-phase (GLS) system for efficient photocatalytic SF6 degradation by Bi2O2CO3, whose efficiency was approximately 20 times that of traditional gas-solid systems. Further, possible degradation mechanisms were demonstrated through the detection of material changes in three phases, respectively. Detailed studies revealed Bi2O2CO3 can in-situ form Bi2S3 heterojunction during the reaction, facilitating carrier separation. Besides, O2 can transform to ·O2− and accelerate the photodegradation process. This approach offered a novel toolbox for SF6 degradation. We predict this method will have a wider range of applications in the field of solar-powered catalytic degradation of extremely stable fluorinated pollutants at lower costs in the future.

Keywords: photocatalyst, gas-liquid-solid, Three-phase interfaces, SF6/air system, Bi2O2CO3