Extent of dissolution determines the structural similarity between dealloyed nanoporous materials synthesized at unrelated dissolution conditions

Most experimental studies on synthesis of nanoporous structures via selective dissolution of electro-active species in metal-alloy nanomaterials report the conditions and the time required to achieve nanoporosity. Depending on the dissolution conditions the timescales of nanoporosity evolution can vary over several orders from sub-second timescales to days, and as such evolution for each condition may appear unrelated. We show that the extent of dissolution (EOD), i.e., the fraction of electroactive atoms dissolved, and not time, is an appropriate descriptor for nanoporosity evolution. Using kinetic Monte Carlo simulations we demonstrate that morphological features obtained over a wide range of temperature, alloy composition, material interactions, etchant concentration and overpotential values are nearly identical for a given EOD. Timescales for different conditions are related by a scaling parameter. Dissolution behavior observed with one experiment can be used to predict results for another experiment, e.g., we relate linear sweep and potential step to constant potential experiments on the basis of EOD. This understanding may be useful for predicting morphology for slow etching/corrosion/leaching conditions from accelerated dissolution experiments as well as design of nanoporous materials. (C) 2018 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved