Tuning the electronic, magnetic, and sensing properties of a single atom embedded microporous C3N6 monolayer towards XO2 (X = C, N, S) gases

Abstract

Two-dimensional frameworks have attracted significant attention due to their great potential in many applications. Among the g-C_xN_y family, C₃N₆ is one of the recently synthesized promising candidates, which exhibits semiconducting behavior. Motivated by its potential, we performed first-principles density functional theory (DFT) calculations to explore the structural, electronic, magnetic, and gas sensing properties of the C₃N₆ ML towards common pollutants, such as XO₂ (X = C, N, and S). We found weak binding between the pristine C₃N₆ ML and XO₂, which was not suitable for efficient gas capture. However, functionalization with a selected transition metal not only altered the electronic and magnetic properties but also improved the sensing behavior of TM–C₃N₆ (TM = Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, and Zn). We have analyzed the adsorption behavior, desorption time, and correlation matrix of TM embedded C₃N₆ towards XO₂ (X = C, N, and S) gases. Electronic structures and magnetic moments of XO₂ adsorbed TM–C₃N₆ depend on the atomic number of the embedded TM atom and the adsorbed gas molecules. We found that the adsorption energies of TM–C₃N₆ systems towards NO₂ gas molecules are stronger in comparison to CO₂ and SO₂ gas molecules, which suggested a selective capture mechanism. Based on our findings, TM–C₃N₆ systems turned out to be promising adsorbent materials for environmentally toxic pollutants.