Ag(111) and its doped surfaces for heavy metal atoms removal from wastewater: DFT calculation analysis

Abstract

Some toxic and harmful water pollutants like Cd, Cr, Pb and other heavy metals are inevitably produced during daily industrial and agricultural productions. In the context of green, environmental protection and sustainable development, the study on how to efficiently remove or recycle these heavy metals and give full play to their commercial potential has become the focus of researchers in recent years. There have been some experimental research results on the removal or recycle of heavy metals, but theoretical researches on metal doping adsorption are not deep enough. Based on density functional theory (DFT), the interactions of heavy metal Cd, Cr and Pb atoms with pure, Mo-doped, Pt-doped and Au-doped Ag(111) surfaces were studied by a first-principles calculation. It was found that Cr and Pb atoms shown chemisorption at all adsorption sites, while Cd atom shown physical adsorption (top and bridge sites) and chemisorption (hollow site). Among them, Mo doping, Pt doping and Au doping did not significantly improve the adsorption properties of Cd atom, but help the adsorption of Cr atom and Pb atom on doped substrates. The most stable adsorption surface for three types of heavy metal atoms is Mo-doped Ag(111) surface, and the most stable adsorption site (adsorption energies are −2.13 eV, −9.57 eV, −4.94 eV, respectively) is hollow site. This research enriches the design of Ag-based catalysts for wastewater treatment.