Exhaled breath analysis by nanosensors is a workable and rapid manner to diagnose lung cancer in the early stage. In this paper, we proposed Al-doped MoSe2 (Al–MoSe2) as a promising biosensor for sensing three typically exhaled volatile organic compounds (VOCs) of lung cancer, namely, C3H4O, C3H6O, and C5H8, using the density functional theory (DFT) method. Single Al atom is doped on the Se-vacancy site of the MoSe2 surface, which behaves as an electron-donor and enhances the electrical conductivity of the nanosystem. The adsorption and desorption performances, electronic behavior, and the thermostability of the Al–MoSe2 monolayer are conducted to fully understand its physicochemical properties as a sensing material. The results indicate that the Al–MoSe2 monolayer shows admirable sensing performances with C3H4O, C3H6O, and C5H8 with responses of −85.7, −95.6, and −96.3%, respectively. Also, the desirable adsorption performance and the thermostability endow with the Al–MoSe2 monolayer with good sensing and desorbing behaviors for the recycle detection of three VOCs. We are hopeful that the results in this paper could provide some guidance to the experimentalists fulfilling their exploration in the practical application, which can also broaden the exploration of transition-metal dichalcogenides (TMDs) in more fields as well.

In this work, the adsorption and sensing behaviors of Rh-doped MoTe2 (Rh-MoTe2) monolayer upon SO2, SOF2, and SO2F2 are investigated using first-principles theory, wherein the Rh doping behavior on the pure MoTe2 surface is included as well. Results indicate that TMo is the preferred Rh doping site with Eb of − 2.69 eV, and on the Rh-MoTe2 surface, SO2 and SO2F2 are identified as chemisorption with Ead of − 2.12 and − 1.65 eV, respectively, while SOF2 is physically adsorbed with Ead of − 0.46 eV. The DOS analysis verifies the adsorption performance and illustrates the electronic behavior of Rh doping on gas adsorption. Band structure and frontier molecular orbital analysis provide the basic sensing mechanism of Rh-MoTe2 monolayer as a resistance-type sensor. The recovery behavior supports the potential of Rh-doped surface as a reusable SO2 sensor and suggests its exploration as a gas scavenger for removal of SO2F2 in SF6 insulation devices. The dielectric function manifests that Rh-MoTe2 monolayer is a promising optical sensor for selective detection of three gases. This work is beneficial to explore Rh-MoTe2 monolayer as a sensing material or a gas adsorbent to guarantee the safe operation of SF6 insulation devices in an easy and high-efficiency manner.