Adsorption of Multiple Toxic Gases by Transition-Metal-Loaded Ti 2 CO 2 : DFT-Based Performance Analysis

This study investigated the adsorption characteristics of CO, NO, NO 2, and NH 3 on Ti 2 CO 2 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 Ti 2 CO 2 . 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 Ti 2 CO 2, among which Ru demonstrated the highest adsorption stability. The incorporation of transition metals significantly modified the electronic structure of Ti 2 CO 2, 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/Ti 2 CO 2, with adsorption energies exceeding 0.5 eV for CO, NO, and NO 2 . Different gases led to varied changes in the system’s work function, and the adsorption of NH 3 significantly reduced the work function. Notably, Rh/Ti 2 CO 2 exhibited optimal adsorption performance under biaxial strain, attributed to enhanced charge transfer and orbital hybridization.