This research is devoted to the investigation of the toxic carbon monoxide gas adsorption mechanisms on the tin dioxide semiconductor. We used density functional theory to describe adsorption processes and found out that the Mars- van Krevelen adsorption mechanism is not responsible for adsorption on (101) and (001) surface orientations of tin dioxide. For (110) and (100) surfaces, after adsorption carbon dioxide molecule forms and desorbs from the surfaces. For (101) surface orientation, carbon monoxide adsorb to the surface’s oxide by carbon atom and stay bonded to it. Charge transfer from the molecule to the surface, which equal to 1.9e calculated by Bader charge analysis. In the case of (001) surface orientation, carbon monoxide adsorb to surface’s oxygen and stay bonded too. Here, we consider half and full surface coverages. It was shown, that during full surface coverage, only one molecule can adsorbs and transfer 2e charge. Electronic density of states calculation was done to explain the increase of surface conductance
