Excellent Gas-Sensitive Capabilities of Co₃(HXTP)₂ for Detecting Combustion Process Gases: A Theoretical Study

Combustion processes produce noxious gases, causing environmental pollution and health risks, which require high-performance sensing materials. Herein, metal-organic framework structures (MOFs) Co₃(HXTP)₂ (X = H, I, T) with superior conductivity and sensing properties are employed based on density functional theory (DFT) calculations. Adsorption energies of Co₃(HXTP)₂@gas are exceptionally outstanding in the realm of gas-sensitive material. Co₃(HXTP)₂ bases exhibit a responsive behavior toward the gas by comparing the work function and have a short recovery time (τ). Our results demonstrate that Co₃(HHTP)₂ (τ = 1.226 s) and Co₃(HITP)₂ (τ = 19.441 s) can serve as gas-sensitive materials for detecting O₂ at 298 K, whereas Co₃(HTTP)₂ (τ = 694.226 s) can be used for CO at 498 K. Moreover, excellent gas-sensitive properties arise from chemical interactions, such as the electron "donation-backdonation" mechanism between gas and substrate (σ → 3d ² and 3d , 3d → π*), and the simultaneous refilling of the d-suborbitals (3d ² → 3d , 3d ) within Co atoms. The descriptor φ demonstrates excellent predictive capability for both the adsorption and response of gas-sensitive materials. Our findings provide valuable insights into the design of gas-sensitive materials in this class of TM₃(HXTP)₂ structures.