Transition metal (Au, Ag, Pt, Pd, Ni) doped MoS2 as gas sensing materials for C4F7N leakage detection: A comparative study

Fluorinated nitrile (C4F7N) has been considered a novel eco-friendly gas insulating medium, while the low toxicity and leakage risk urgently urge the development of C4F7N gas sensor. Herein, we analyzed the sensing performance of transition metal doped MoS2 to C4F7N based on the density functional theory (DFT). Au, Ag, Pt, Pd and Ni can be strongly chemically doped on the surface of MoS2. The adsorption energy, charge transfer, deformation charge density and density of states were explored. The adsorption energies of Au, Ag, Pt, Pd and Ni-doped MoS2 for C4F7N are -0.55 eV, -0.59 eV, -1.43 eV, -0.95 eV and -1.59 eV, respectively, which belong to chemical adsorption. Furthermore, the sensitivity and recovery performance were analyzed based on frontier orbital and transition state theories. The results show that all five atom-MoS2 exhibit good sensitivity with conductance changes of more than 80 %, but only Pd-MoS2 can achieve a recovery time in the order of seconds at lower temperatures (1.01 s at 125 °C). The subsequent analysis shows that O2 and H2O in the air do not attach to the surface of Pd-MoS2, confirming its good stability. With its high sensitivity, satisfactory recovery time and strong stability, Pd-MoS2 shows promising potential for C4F7N leak detection engineering applications.