First-principle investigation of CO, CH₄, and CO₂ adsorption on Cr-doped graphene-like hexagonal borophene

It is important for life safety and scientific research to design new sensing materials for detecting CO, CH₄, and CO₂ from the environment. We theoretically designed a new Cr-doped graphene-like hexagonal borophene (CrB₆) as potential sensor material for these gases. Carrying out first-principle density-functional calculations, we calculated the adsorption energy, band structure, adsorption distance, charge transfer, charge density difference, density of states, and partial density of states of CO, CH₄, and CO₂ gas molecules absorbed on CrB₆ monolayer. The calculated results show that the adsorption behavior of CO is different from those of CH₄ and CO₂. CO adsorbed on CrB₆ monolayer prefers chemisorption with the adsorption energy of - 2.59 eV while CH₄ and CO₂ adsorbed on CrB₆ monolayer prefer physisorption with the adsorption energy of - 0.72 and - 0.69 eV. As a result, the different adsorption behaviors have significant influence on the band structures and density of states of CrB₆ monolayer. We hope that our results can help experimentalists synthesize better sensor materials based on hexagonal borophene.