Copper based nanomaterials have proven to improve plant immune response in diseased soils through the release of Cu cations which are used as micronutrients by the plant. The morphology of these nanomaterials can be controlled through the synthesis conditions to produce nanosheets that are (001) facet dominated or nanoparticles that have an ensemble of exposed surface planes. The Cu will be in different bonding environments given the cut of the surface which will change the release favorability. Additionally, upon exposure to organic acids, etching has been observed on the nanosheet but on the side faces of the material, which we hypothesize is also connected to surface Cu bonding environemnts. Through a DFT + thermodynamics approach we can model metal release from individual facets to relate back to experimental findings. In this study, we model CuO (hkl) surfaces (with h, k, and l being 0 or 1). For each facet, we determine the stoichiometry that minimizes the surface free energy, starting from the assumption that protonation of under-coordinated oxygen and/or hydroxylation of undercoordinated copper sites that lead to charge balance in the slab dominate. Once the CuO-water interface stoichiometry is determined, we model metal release as a Cu-OH vacancy formation, combining DFT total energies with tabulated thermochemical data. From the trends in metal release, we back out understanding of how surface Cu coordination and facet morphology affect the thermodynamics of the process. These insights are used to form a basis for guiding the design of Cu nanomaterials with controlled release properties.

DFT + Thermodynamics Modeling of CuO Facet Stability and Metal Release

Fall 2022 abstracts, posters, and presentations will launch in mid-September.

ACS Fall 2022

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.