Adsorption of SF<sub>6</sub> Decomposed Species on Ti<sub>3</sub>C<sub>2</sub>O<sub>2</sub> and Ti<sub>3</sub>C<sub>2</sub>F<sub>2</sub> with Point Defects by DFT Study
Ling‐Yan Kong, Xiongyi Liang, Xiangxuan Deng, Chen Guo, Chi‐Man Lawrence Wu
Abstract
Abstract The high specific surface area and electrical conductivity of new 2D metal carbide MXenes make them become a suitable candidate as sensor platform of the gas sensor. Herein, density functional theory (DFT) is implemented to investigate the adsorption of the SF 6 decomposed gases (SOF 2 , SO 2 , and H 2 S) on Ti 3 C 2 O 2 , Ti 3 C 2 F 2 , and Ti 3 C 2 (OH) 2 . Modification of the surface of Ti 3 C 2 O 2 and Ti 3 C 2 F 2 by O and F point vacancy, respectively, is then performed to improve the adsorption performance. The band structure, charge density differences, electron localization function (ELF), and projected density of states (PDOS) are investigated to study the adsorption mechanism. The results indicate that as compared with the weak adsorption on pristine Ti 3 C 2 O 2 and Ti 3 C 2 F 2 , the SOF 2 , SO 2 , and H 2 S gas molecules tend to be chemisorbed on Ti 3 C 2 O 2 and Ti 3 C 2 F 2 with point vacancy with high adsorption energies. Furthermore, the study of electronic properties suggests that all adsorption systems show high electronic conductivity and the exposed Ti atoms by point defect mainly contribute to the formation of ionic bond with high adsorption energy. Thus, the present results show that Ti 3 C 2 O 2 and Ti 3 C 2 F 2 with point vacancy are feasible novel sensing materials to detect SF 6 decomposed species with high sensitivity and low electronic noise. The sensitive detection capability of SO 2 is particularly noticeable.