Identifying of Pure and Defected Ti2C Materials Using Gas Probe Molecules: First Principles Calculations

Employing first principles calculations, we systematically investigated the geometrical and electronic structures of pure, titanium defected (DTi) and carbon defected (DC) Ti2C materials. We found the defected Ti2C exhibits stronger metallic property than pure Ti2C due to the enhanced density of Ti‐d orbital state near the Fermi level. We then studied the adsorption as well as the infrared spectrum (IR) response of the four kinds of gas molecules (CH4, NH3, CO and NO) on pure, DTi and DC Ti2C surfaces. Simulations show that CO and NO molecules are chemically adsorbed on all Ti2C surface with similar adsorption sites. However, CH4 and NH3 molecules would be dissociated on Ti2C surface. Negative values of crystal orbital Hamilton population as well as the PDOS calculations show that the red shift in IR spectra of CO and NO molecules originates from the decreasing bonding strength of probe molecules. The present work provides rich insight for the adsorption and identification for different Ti2C materials. Identification of pure and defected Ti2C: The geometrical and electronic structures of pure, titanium and carbon defected Ti2C materials were investigated. We also analyze the adsorption of CH4, NH3, CO and NO on different Ti2C surface. Due to the good adsorption and IR response, CO and NO are selected as the ideal probe molecules to identify the different Ti2C materials.