Adsorption and sensing behaviors of SF6 decomposed species on Ni-doped C3N monolayer: A first-principles study

To give a first insight into the transition metal (TM) doped C3N monolayer for application of chemical gas sensors, we using first-principles theory in this paper investigated the adsorption performance of Ni-doped C3N (Ni-C3N) monolayer upon three SF6 decomposed species, including SO2, SOF2, and SO2F2. We first analyzed the stability of Ni-doping on the C3N monolayer where two sites were considered, namely the N-vacancy and C-vacancy site. It is found that N-vacancy would be the preferred site with higher binding energy for anchoring Ni atom, which is thereafter defined as the model to perform the adsorption processes. The results of gas adsorption indicated that Ni-C3N monolayer possesses strong adsorption ability towards three gaseous molecules, making them stably adsorbed on the Ni site with strong chemical bonds. Besides, the analyses of band structure and density of state (DOS) not only verify these findings but also expound the underlying mechanism for gas sensing using Pd-C3N monolayer. In addition, the analysis of the optical property for Ni-C3N monolayer suggests its potential to be optical gas nanosensors based on ultraviolet spectrum method. Our calculations would be meaningful to explore the chemical sensing application of Ni-C3N monolayer as a novel member in the sensor family.