Influence of defect and doping on the sensitivity and adsorption capacity of Zr2CO2 toward PH3 gas

Abstract

In this study, the potential application of the Zr2CO2-MXene structures as PH3 sensors and adsorbents for industrial or living applications was investigated using the first-principles approach of density functional theory (DFT). The adsorption of PH3 on pristine, O-defected, and transition metal (TM; such as Cr, Mn, Fe, Co, Y, Mo, Ru, Rh)-doped Zr2CO2 structures was explored. The results showed that the introduction of TM dopant improved the Zr2CO2 activity more than the O-vacancy. The large adsorption energy, short interaction distance, and high charge transfer suggested chemisorption of PH3 molecules on TM-doped Zr2CO2. After the PH3 molecule was adsorbed, the band gap of Zr2CO2 with O-vacancies, Co-doped Zr2CO2, and Ru-doped Zr2CO2 decreased by 0.132 eV, and increased by 0.065 eV, 0.073 eV, respectively. The changes in band gap generated an electrical signal that were used for PH3 detection; thus, Zr2CO2 with O-vacancies and Co– and Ru-doped Zr2CO2 can be used as effective PH3 sensors because of their high sensitivity. Fe- and Rh-doped Zr2CO2 also showed promising function as adsorbents for PH3 gas molecules because of their high adsorption stabilities and long recovery times. After adsorption of six PH3 molecules, their adsorption energies on Fe- and Rh-doped Zr2CO2 were −1.142 eV and −1.135 eV, with recovery times of 1.49 × 107 s and 1.12 × 107 s, respectively. The findings of this study offer novel insights for the development of MXene-based sensors and adsorbents.