NO adsorption and temperature programmed desorption on K2CO3 modified activated carbons

Abstract

Fuel cell stacks as the automotive power source can be severely poisoned by a trace amount of NOx in atmosphere, which makes it necessary to provide clean air for fuel cell vehicles. In this work, activating commercial activated carbons with K2CO3 for the large enhancement of NO capture was studied. K2CO3 modified activated carbons (K2CO3 ACs) were prepared by impregnating activate carbons in K2CO3 solution under ultrasound treatment, followed by temperature programmed baking at 800 °C. The dynamic NO flow tests on K2CO3 ACs at room temperature indicated that NO adsorption capacity reached the maximum (96 mg/g) when K2CO3 loading was 19.5 wt%, which corresponded to a specific surface area of 1196.1 m2/g and total pore volume of 0.70 cm3/g. The ten-fold enhancement of NO adsorption on K2CO3 ACs compared to the unimpregnated activated carbon was mainly attributed to the formation of potassium nitrite, which was confirmed by FTIR and temperature programmed desorption measurements. Regeneration tests of NO adsorption on the optimum sample revealed that 76% of the NO adsorption capacity could be remained after the fourth cycle.