Ab-initio density functional theory study of a WO 3 NH 3 -sensing mechanism

WO 3 bulk and various surfaces are studied by an ab-initio density functional theory technique. The band structures and electronic density states of WO 3 bulk are investigated. The surface energies of different WO 3 surfaces are compared and then the (002) surface with minimum energy is computed for its NH 3 sensing mechanism which explains the results in the experiments. Three adsorption sites are considered. According to the comparisons of the energy and the charge change between before and after adsorption in the optimal adsorption site O 1c , the NH 3 sensing mechanism is obtained.