(189ad) Computer-Aided Description of Materials Stability at the Nanoscale

Authors: 
Taylor, M. G., University of Pittsburgh
Mpourmpakis, G., University of Pittsburgh
Nanomaterials (e.g. alloyed metal nanoparticles (MNPs)) find diverse applications in fields from catalysis to medicine where their unique properties vastly differing from bulk (e.g. high catalytic activity, distinct bandgaps) are highly desirable. The properties of nanomaterials are largely determined by their structure [1-2], but understanding of the nanomaterials stability with structure variation (i.e morphology and chemical ordering) remains limited. The challenges encountered in deciphering structure-dependent thermodynamic stability in nanomaterials are i) the intractable number of potential nanomaterial morphologies and chemical ordering within each unique structure (e.g. in bimetallic MNPs) and ii) the presence of ligands that bind the nanomaterials surface to stabilize them at the nanoscale. Herein, we highlight our recent examples on gaining physical insights and accurately describing the stability of nanomaterials addressing both the aforementioned challenges, through first-principles-based computational modeling. First, we demonstrate doping/alloying energetics alongside a new thermodynamic stability model we developed for atomically-precise ligand protected nanoclusters that rationalize a series of experimental observations. [3-6] Second, we introduce a bond-centric model able to accurately describe alloy MNP stability of practically any MNP morphology and chemical composition. [7] Both examples make strides towards describing nanoparticle stability as a function of morphology and chemical composition, significantly accelerating nanomaterials discovery.

References

[1] M. G. Taylor, N. Austin, C. Gounaris, & G. Mpourmpakis, Catalyst Design Based on Morphology and Environment Dependent Adsorption on Metal Nanoparticles. ACS Catalysis 5, 6296–6301 (2015).

[2] J. Chung, I. Granja, M. G. Taylor et al. Molecular modifiers reveal a mechanism of pathological crystal growth inhibition. Nature 536, 446–450 (2016).

[3] M. G. Taylor, G. Mpourmpakis, Thermodynamic Stability of Ligand-Protected Metal Nanoclusters. Nature Communications 8, 15988 (2017).

[4] Q. Li et al., Reconstructing the Surface of Gold Nanoclusters by Cadmium Doping. Journal of the American Chemical Society 139, 17779-17782 (2017).

[5] Q. Li, K. J. Lambright, M. G. Taylor et al., Molecular “surgery” on a 23-gold-atom nanoparticle. Science Advances 21, 1-8 (2017).

[6] Q. Li, M. G. Taylor et al., Site-selective substitution of gold atoms in the Au24(SR)20 nanocluster by silver. Journal of Colloid and Interface Science 505, 1202-1207 (2017).

[7] Z. Yan, M. G. Taylor, A. Mascareno, G. Mpourmpakis, Size-, Shape-, and Composition-Dependent Model for Metal Nanoparticle Stability Prediction. Nano Letters 18, 2696-2704 (2018).