Adsorption and work function type sensing of SF6 decompositions (SO2, SOF2, SO2F2, H2S and HF) based on Fe and Cu decorated B4CN3 monolayer. A first-principles study

Abstract

During frequent arc-quenching operations, SF₆ gas in SF₆ power circuit breakers decomposes into sulfur-based gases, which eventually causes weakening of quenching ability of SF₆ gas. Therefore, such decompositions must be sensed and captured timely to avoid any malfunctioning of SF₆ circuit breaker. Here we investigate the sensing/adsorption and release of SF₆ decompositions (SO₂, SOF₂, SO₂F₂, H₂S, and HF) on a monolayer B₄CN₃ through first-principles calculations. Pure B₄CN₃ is unable to capture gas molecules due to insufficient adsorption energy, resulting in their rapid release. However, with Fe and Cu decoration on B₄CN₃, adsorption and release are greatly improved. The mechanism included evaluating band structure, work functions (Φ), and transport transmission (I-V). The order of gas adsorption/sensitivity of Fe and Cu decorated B₄CN₃ to target gases is SOF₂ > SO₂F₂ > SO₂ > H₂S > HF. Moreover, despite having lower adsorption energies, Cu decorated B₄CN₃ is more sensitive to all gas molecules than Fe decorated, indicating no direct impact of higher adsorption energy to sensitivity. Gas molecule release time at room temperature can be reduced to nanoseconds either by rising the temperature to 499 K or by just exposing to UV radiation. Our study presents theoretical insights into the gas sensing capabilities of Fe and Cu decorated B₄CN₃ monolayers for SF₆ decompositions.