Single-atom lead ion adsorption behavior on Ti2CO2 MXene under different electrode potentials

Abstract

First-principles calculations, particularly density functional theory (DFT) combined with D3 dispersion correction (DFT+D3), have proven to be valuable tools in simulating the adsorption of lead ions on Ti₂CO₂ surfaces. However, conventional theoretical models assume electrically neutral systems under vacuum conditions, neglecting the solvent environment and electrode potential's crucial effects. This study employed an implicit solvent model, treating the solvent as a continuous and homogeneous medium to capture the influence of different solvents by varying their dielectric constants. Additionally, the role of electrode potential on the adsorption behavior of lead ions on Ti₂CO₂ surfaces was explored. The findings demonstrated that electrode potential significantly affected lead ion adsorption with adsorption strength increasing as the electrode potential decreases. This observation was supported by electronic structure analyses, such as the density of states, band structure and ICOHP. This study provides important insights into the influence of electrode potential on metal ion adsorption on MXene materials, offering a theoretical foundation for the design and optimization of MXene-based adsorbents for environmental applications.