pH dependent reactivity of boehmite surfaces from first principles molecular dynamics

• Published in: Physical chemistry chemical physics : PCCP Vol. 24; no. 23; pp. 14177 - 14186
• Main Authors: Smith, William, Pouvreau, Maxime, Rosso, Kevin, Clark, Aurora E
• Format: Journal Article
• Language: English
• Published: England Royal Society of Chemistry 15.06.2022; Royal Society of Chemistry (RSC)
• Subjects: Boehmite; First principles; Interfacial properties; Molecular dynamics; Nanoparticles
• ISSN: 1463-9076; 1463-9084
• DOI: 10.1039/d2cp00534d

pH dependent interfacial chemistry depends upon the distribution and respective p K a values of different surface active sites. This is highly relevant to the chemistry of nanoparticle morphologies that expose faces with varying surface termination. Recent synthetic advances for nanoparticles of various minerals, including AlO(OH) (boehmite), present an excellent opportunity to compare and contrast predicted surface p K a on low Miller index planes so as to reinterpret reported interfacial properties ( i.e. , point of zero charge - PZC) and reactivity. This work employs ab initio molecular dynamics and empirical models to predict site-specific p K a values of accurate (benchmarked) surface models of boehmite. Using the different surface site populations, the PZC is determined and the influence this has upon reported interfacial chemistry is described. Accurate determination of surface p K a values (calculated using free energy methods) and site populations enable prediction of pH dependent properties of boehmite, including nanoparticle morphology and adsorption.