Adsorption of Multiple Toxic Gases by Transition-Metal-Loaded Ti₂CO₂: DFT-Based Performance Analysis

This study investigated the adsorption characteristics of CO, NO, NO₂, and NH₃ on Ti₂CO₂ materials modified by transition metals Ru, Rh, and Pd. Density functional theory (DFT) calculations were used to investigate the effect of transition metal (Ru, Rh, Pd) loading on the adsorption properties of Ti₂CO₂. The research process included creating and evaluating the stability of modified models, determining essential parameters such as adsorption energy and charge transfer, and analyzing the effects on electronic properties. The findings indicated that transition metal (TM) atoms could adsorb stably on Ti₂CO₂, among which Ru demonstrated the highest adsorption stability. The incorporation of transition metals significantly modified the electronic structure of Ti₂CO₂, optimizing its electrical conductivity within a favorable range and enhancing gas adsorption ability. This optimal conductivity window balances efficient charge transfer with sufficient relative resistance change, which is critical for chemiresistive signal transduction. Chemisorption dominated the gas adsorption on TM/Ti₂CO₂, with adsorption energies exceeding 0.5 eV for CO, NO, and NO₂. Different gases led to varied changes in the system's work function, and the adsorption of NH₃ significantly reduced the work function. Notably, Rh/Ti₂CO₂ exhibited optimal adsorption performance under biaxial strain, attributed to enhanced charge transfer and orbital hybridization.