Connectivity-list based characterization of 3D nanoporous structures formed via selective dissolution

Formation of complex 3-D nanoporous structures via selective dissolution of an electroactive component in a bulk material is commonly encountered in corrosion, electrochemistry and materials preparation. We report a characterization technique to rapidly calculate the size distribution of nanoporous ligaments and facets from molecular-scale models that reveal the evolution of nanoporous morphology reaching experimental timescales. The key feature of our approach is the use of connectivity lists for sites, which enables rapid quantification of several million-atom large nanoporous structures while being sufficiently versatile to handle non-cylindrical cross-sections, detachment of ligaments from the main structure, and crystal facet-related quantities. As an application of this characterization tool, we find that the alloy composition has a significant effect on the charge transfer and the structure whereas the starting shape (nanowires, nanocubes and nanoparticles of same size) has a subtle effect particularly at early-to intermediate stages of nanoporosity evolution. These conclusions cannot be arrived at by visual examination of the simulated structures. Ascertaining differences in structural features upon changing synthesis conditions using our approach will be relevant to porous materials such as those encountered in corrosion, batteries and geological systems. (C) 2017 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.