Ab initio study of CNT NO 2 gas sensor

Abstract

NO 2 gas adsorption, diffusion, and reaction on a single walled carbon nanotube (SWNT) surface are studied using ab initio simulations. The small diffusion barriers of NO 2 on SWNT surface suggest that NO 2 molecules can produce NO and NO 3 through chemical reactions. From the estimation of diffusion barriers and binding energies of NO 2, NO, and NO 3 on a SWNT surface, we show that NO 3 is the most likely long-lived species on SWNT. This finding enables us to explain why the experimental recovery times of NO 2 gas sensors have been measured to be as long as 12 h.