First-Principles Study on the Potential of Monolayer Ti₂N as an Adsorbent for Dissolved H₂ and C₂H₂ Gases in Oil

The potential of the Ti2N monolayer in removing CH4, C2H2, and H2 mixture gases from transformer oil has been studied based on first-principles calculation. By comparing the total energy of ferromagnetic and antiferromagnetic structures of Ti2N, it is confirmed that the energy of ferromagnetic structure is the lowest. On this basis, the adsorption effects of the Ti2N monolayer on these three gases and the electronic properties before and after adsorption were investigated. Ti2N monolayer provides a large number of Ti atom active sites with abundant d electrons for adsorption. Its adsorption energies to H2 and C2H2 are −2.964 and −5.527 eV, respectively. For C2H2 adsorption, the sp hybridization within the molecule is destroyed, and then turn into sp2 hybridization according to the description of electron deformation density. In addition, only weak interaction exists between Ti2N monolayer and CH4, and the adsorption energy is only −0.214 eV with almost no charge transfer. The investigation shows that Ti2N can be used as a potential adsorbent for H2 and C2H2 or as a potential material for the purifying CH4 from a H2/ CH4/C2H2 mixture.