Mechanism of NOx sensing on WO3 surface: First principle calculations

Lama Saadi (1) , Caroline Lambert-Mauriat (1) , Vincent Oison (1) , Hela Ouali , Roland Hayn (1)

1 IM2NP - Institut des Matériaux, de Microélectronique et des Nanosciences de Provence

Computational study of NO 2 sensing on the WO 3 (001) surface is presented. Our ab initio calculations reveal a two-step process of NO 2 detection on the WO 3 surface. In a first step the NO 2 molecule is dissociated at an oxygen vacancy site, but a NO molecule remains adsorbed. In a second step NO is re-oxidized into NO 2 by O 2 of the surrounding air leading to the resistance increase which is experimentally observed. We also calculate the adsorption energy of NO on stoichiometric and non-stoichiometric WO 3 surfaces and propose a method for the NO detection.

Mots clés: WO 3 surface; gas sensor; ab initio calculations; NO 2 detection

Domaines: Sciences de l'ingénieur [physics]; Micro et nanotechnologies/Microélectronique; Science des matériaux [cond-mat.mtrl-sci]

Lama Saadi, Caroline Lambert-Mauriat, Vincent Oison, Hela Ouali, Roland Hayn. Mechanism of NOx sensing on WO3 surface: First principle calculations. Applied Surface Science, 2014, 293, pp.76 - 79. ⟨10.1016/j.apsusc.2013.12.095⟩. ⟨hal-01730734⟩