Noble metal (Pt or Pd)-decorated atomically thin MoS2 as a promising material for sensing colorectal cancer biomarkers through exhaled breath

Early-stage disease and cancer diagnosis are of particular importance for effective patient identification as well as their treatment. Breath analysis is a promising method for this purpose which can help to detect disease biomarkers. Benzaldehyde and Indole gas molecules as members of volatile organic compounds (VOCs) are composed of a proportion of the exhaled breath and changes in the level of them from breath can be considered for colorectal cancer biomarkers. Due to these incentives, we scrutinized the sensing behavior of Molybdenum disulfide (MoS2) toward Benzaldehyde and Indole gas. We inspected the adsorption of the molecules on the pristine and Pd-, Pt-decorated MoS2 by employing density functional nonequilibrium Green's function (DFT-NEGF). It was disclosed that the molecules were weakly adsorbed upon the pristine MoS2. Howbeit, after the decoration of the surface, the adsorption energy and charge transfer of the molecules were improved greatly. On the other hand, the band gap was decreased after metal decoration. For example, adsorption energy of -2.37eV and band gap of 1.32eV were achieved by interaction of Indole with Pd-decorated MoS2 and it can be desorbed under UV light and at temperature of 698K with recovery time of 12.8s. Ergo, our analysis would help us better understand the adsorption mechanism of Pd- and Pt-decorated MoS2-based gas sensors. It may open a new route in early disease detection and colorectal cancer monitoring.