Two-dimensional PdPS and PdPSe nanosheets: Novel promising sensing platforms for harmful gas molecules

Motivated by the latest experimental advances in the fabrication of penta-PdPS and penta-PdPSe layered materials, in this work we theoretically explore the PdPS and PdPSe monolayers as novel platforms for the detection of harmful gas molecules, including CO, CO2, NH3, NO, and NO2. We found that PdPS and PdPSe monolayers are stable semiconductors. Next, we systematically assessed the most favorable adsorption configurations and examined the electronic properties of gas-adsorbed PdPS/PdPSe monolayers. It is manifested that CO, CO2, and NH3 gas molecules are physisorbed on the PdPS, and PdPSe monolayers, while upon the adsorption of NO, and NO2, the electronic structure changes significantly. It is moreover realized that after adsorption of NO, and NO2, respectively, over the PdPS monolayers energies of 0.98, 1.01 eV are released, and over PdPSe energies of 1.12, and 1.21 eV are emitted. According to calculated recovery time, the PdPS platform yields a quick recovery after exposure to NO, and NO2 with times of 4.33 and 11.9 s, respectively, at room temperature and under UV light. PdPSe monolayers exhibits a recovery time of 1.74 s at 498 K and under visible light after interaction with NO2. Our study results suggest that PdPS and PdPSe nanosheets are eminently promising for detecting NO2 molecule.