First-principles study on hexagonal WO3 for HCHO gas sensing application

Abstract

The adsorption energy, electronic structure, density of states, and electron population for adsorption of HCHO on the hexagonal WO3 (h-WO3) (001) surfaces were investigated by density functional theory calculations. The adsorption energy of HCHO molecule on W and O sites of WO-terminated h-WO3 (001) surface was -0.309 and -0.432 eV compared with the value at -1.936 eV for HCHO molecule on O-terminated h-WO3 (001) surface. According to the calculated results, the adsorption of HCHO on h-WO3 (001) surface was spontaneous with physical adsorption on WOterminated h-WO3 (001) surface and chemisorption on O-terminated h-WO3 (001) surface. The charge transfer from adsorbed HCHO molecule to WO3 (001) surface was confirmed by the Mulliken population analysis, which suggested the potential application of h-WO3 for HCHO gas detection.