Rhn (n = 1, 2) modified C3N: A potential candidate for H2S, SOF2, SO2F2 and SO2 detection and scavenging

Abstract

Since high voltage insulation equipment fault and aging are always accompanied with insulation gas decomposition, it is critical to monitor and scavenge SF6 decomposition gases. In this paper, based on density functional theory, Rh and Rh2 doped C3N are utilized to detect SF6 decomposition species (H2S, SO2, SOF2, and SO2F2). The ideal binding energy of the most stable structures are −2.769 eV (Rh-C3N) and −3.482 eV (Rh2-C3N), respectively. The Rhn-C3N composite structure considerably increases the adsorption behaviors and electrical properties of SF6 decomposition species. After gas molecules adsorption, changes of differential charge density, density of state, work function, and theoretical recovery time further support the sensing characteristic of composite structures. For various target gases, the results reveal that Rh-C3N and Rh2-C3N exhibit distinct adsorption types. SO2 and H2S adsorption belongs to physical adsorption, while the type of SOF2 and SO2F2 adsorbed system is chemical adsorption. Even at high temperatures, the good recovery time (30.32 s and 21.77 s) for H2S adsorption systems can be acquired. The results demonstrate that Rhn-C3N (n = 1,2) is a novel carbon-based SF6 gas sensing material that can be used to diagnose SF6 decomposition in SF6 electrical equipment insulation faults.