Functionalized Mo₂BX₂ (X = H, OH, O) MBenes as a promising sensor, capturer and storage material for environmentally toxic gases: A case study of 1T and 2H phase

MBenes analogous to MXenes, exfoliated from the bulk MAB phase (M = transition metal, A = III_A and IV_A group, and B = boron) have appeared as promising two dimensional (2D) materials due to their intriguing properties. Here, we report the 2D 1T-2H-phase of Mo₂B with their functionalized derivatives Mo₂BX₂ (X= H, OH, O) and investigate their structural, electronic, and adsorption behavior of toxic gases using the first-principles calculations. This study finds that pristine and functionalized MBenes have dynamic and thermal stability and possess metallic nature in both phases. Based on adsorption behavior and comparison with other 2D materials, we find that pristine MBenes are a desirable adsorbent for NO₂, SO₂, and CO₂ capture. In contrast, the moderate adsorption energies for functionalized MBenes-NH₃ systems reveal good sensitivity for NH₃ gas detection in both phases. In particular, 2H-Mo₂BH₂ has higher CT (−0.11e) and appropriate adsorption energy (−0.30 eV), leads a shorter recovery time. Further, DOS calculations reveal that the electrical conducting behavior of MBenes makes them suitable for NH₃ detection with a short recovery time. Our results would provide the first insight into the surface-functionalized effect on the structural and electronic properties of the MBenes, and shed light on the application of MBenes for the sensing and catalyst of typical toxic and greenhouse gases, respectively.