Predicting Surface Energies and Particle Morphologies of Boehmite (γ-AlOOH) from Density Functional Theory

Particle morphology is an important property affecting the reactivity of solid phases. The aluminum oxyhydroxide boehmite (γ-AlOOH) is one example for which particle morphology has relevance to geochemistry, environmental management, and catalysis. Accurate predictions of the morphology of boehmite particles are currently missing, and the dependence of these predictions on the level of theory and complexity of the physics involved is not known. Density functional theory calculations were therefore performed for a wide range of exchange-correlation (XC) functionals, including a hybrid functional, to calculate the energetics of the four main low-index surfaces of boehmite ((100), (010), (001), and (101)) in aqueous conditions and predict equilibrium and growth morphologies. The results highlight the critical need for converged plane-wave basis sets to obtain accurate surface energies as well as the strong influence the XC functional can have on surface energies and water adsorption energies. The predicted m...