The effect of Fe, Co and Ni doped Ti 2 CO 2 on sensitivity to toxic gases: A DFT study

Abstract

MXenes are a new class of two-dimensional (2D) materials that have attracted significant attention in numerous sensor applications due to their excellent properties. To address the urgent need for the efficient detection of toxic gases (such as CO, NO, SO 2 , and HF), the gas-sensing response mechanism of transition metal (TM) -doped MXene Ti 2 CO 2 on oxygen-sealed surfaces has been systematically investigated using density functional theory (DFT). In this study, three transition metal dopants: Fe, Co and Ni are investigated and factors such as band structure, density of states, adsorption energy and charge transfer are analyzed. Meanwhile, the key performance indicators of the sensor, desorption time and sensitivity are also evaluated. The results show that gas molecules undergo physical adsorption on the pristine Ti 2 CO 2 surface. When vacancy defects and TM doping are introduced, physisorption transforms into chemisorption. The density of states analysis reveals that the hybridization between the dopant's 3d orbitals and gas molecules enhances adsorption stability. Vacancies and TM doping enhance the material's responsiveness to toxic gases, and the TM doping system can also selectively detect toxic gases. These findings provide a reference for the design and optimization of MXene -based gas sensors.