Bimetallic Phthalocyanine Monolayers as Promising Materials for Toxic H2S, SO2, and SOF2 Gas Detection: Insights from DFT Calculations

The development of a high-performance gas sensor for the rapid and efficient detection of harmful SF6 decomposition gases (H2S, SO2, and SOF2) is crucial for equipment environmental monitoring and safeguarding human health. In this work, first-principles calculations were conducted to assess the adsorption performance and sensing characteristics of these decomposition gases on two-dimensional metal-dimer-modified phthalocyanine (Mn2Pc, Tc2Pc, and MnTcPc) surfaces. The results demonstrate that the Mn2Pc, Tc2Pc, and MnTcPc monolayers possess enhanced structural stability. The Mn2Pc, Tc2Pc, and MnTcPc monolayer materials show strong adsorption capabilities (|Eads| > 0.90 eV) and significant electron transfer (|Qt| > 0.017 e) and interact favorably with the aforementioned toxic gases, indicating their superior adsorption capacities for SOF2, SO2, and H2S. The microscopic interaction mechanisms between SF6-decomposed gas molecules and the Mn2Pc, Tc2Pc, and MnTcPc nanosheets are elucidated through analyses of electron density distribution, differential charge distribution, and density of states. Furthermore, upon absorption of H2S, SO2, and SOF2, the work function and band gap energy of the Mn2Pc, Tc2Pc, and MnTcPc monolayers undergo significant changes, and the magnetic moments of the Mn2Pc, Tc2Pc, and MnTcPc monolayers also exhibit substantial alterations, suggesting high sensitivity to H2S, SO2, and SOF2. Considering the balance of adsorption strength, sensitivity, and recovery time, the single-layer films of Mn2Pc, Tc2Pc, and MnTcPc are deemed to be gas-sensing materials with significant potential, suitable for the development of sustainable gas sensors targeting H2S, SO2, and SOF2 with effective recovery capabilities.