Adsorption and sensing SF6 decomposed gases (SO2, SO2F2, SOF2, H2S, and HF) on Ti and Co decorated B4CN3 monolayer- A DFT study

Abstract

With frequent switching of high power and high voltage circuits, SF6 gas decomposes into low fluorine gases, which causes deterioration of SF6 gas. Therefore, such decomposed gases must be sensed and captured timely for the smooth operation of the SF6 power circuit breaker (PCB). The current study aimed to employ density functional theory (DFT) calculations to explore the adsorption and gas sensing properties of SF6 decomposed products (SO2, SO2F2, SOF2, H2S and HF) on titanium (Ti) and cobalt (Co) decorated B4CN3 monolayer. The findings revealed that pure B4CN3 could not capture gas molecules with sufficient adsorption energy and faced instantaneous release. Similarly, Ti and Co decoration can significantly activate the B4CN3 for adsorption and gas sensing. Adsorption analysis showed that SO2, SO2F2, SOF2, H2S, and HF chemically adsorbed on Ti decorated B4CN3 monolayer having adsorption energy of −1.31, −1.61, −1.35, −1.20, and −1.01 eV. Whereas, gas adsorption on Co decorated B4CN3 has −1.29, −1.58, −1.31, −1.18, and −0.95 eV, respectively. The gas sensing mechanism was evaluated by calculating band structure, work functions, and transport transmission. Despite having comparatively lower adsorption energies, Co decorated B4CN3 was found to be more sensitive to all gas molecules than Ti decorated B4CN3. The release time of gas molecules at room temperature can be shortened to nanoseconds either by rising temperature to 498 K or by just UV exposure at 298 K. Our study provides some significant theoretical insights into the gas sensing abilities of Ti and Co decorated B4CN3 monolayer for sensing SF6 decomposed products.