Affecting factors of electrified soot combustion on potassium-supported antimony tin oxides

Abstract

Elimination of soot particulates using catalytic combustion technologies at lower temperatures remains a big challenge for diesel engines with the ever-lowering emission temperatures. We recently reported an electrified catalysis strategy that decreased the soot ignition temperature for 50% conversion (T50) to below 75 °C on potassium-supported antimony-tin oxides (K/ATO) (Mei et. al., Nature Catalysis, 2021, 4: 1002). However, the detailed affecting factors were not present for the sake of promptly enjoying this exiting progress. Herein, three important factors, including K loading amounts, electric power ramp rates and nitrogen oxides (NOx), for the Electrically Powered Programmed Oxidation (EPPO) of soot were investigated on K/ATO. First, K loading enhances soot ignition but much higher K content (>1 wt%) is detrimental due to spoiling catalyst conductivity. Second, elevating the electric power ramp rate to 0.1 W min−1 reaches an apex with the promise of the balance of soot ignition conversion and energy efficiency. Finally, NOx, a promoter in traditional thermal catalysis, is overwhelmed by the tremendous active oxygen trigged from the electrification process, showing no effects on soot ignition. These findings are instructive to rational catalyst designs and vital to accelerate the industrial applications of the newly developed electrified catalytic soot combustion in the hybrid electric vehicle (HEV) aftertreatment system.