A Stunt of Sustainability: Artificial Humic Substances Can Generate and Stabilize Single Fe0 Species on Mineral Surfaces

Abstract

Iron species are omnipresent in fertile soils and contribute to biological and geological redox processes. Here, we show by advanced electron microscopy techniques that an important, but previously not considered iron species, single atom Fe0 stabilized on clay mineral surfaces, is contained in soils when humic substances are present. As the concentration of neutral iron atoms is highest under frost logged soil conditions, their formation can be attributed to the action of a then reductive microbiome. The Fe0/Fe2+ couple is with −0.04 V standard potential highly suited for natural environmental remediation and detoxification, and its occurrence can help to explain the sustained auto-detoxification of black soils.