title: Post-Synthetic Anisotropic Wet-Chemical Etching of Colloidal Sodalite ZIF Crystals.
abstract: Controlling the shape of metal-organic framework (MOF) crystals is important for understanding their crystallization and useful for myriad applications. However, despite the many advances in shaping of inorganic nanoparticles, post-synthetic shape control of MOFs and, in general, molecular crystals remains embryonic. Herein, we report using a simple wet-chemistry process at room temperature to control the anisotropic etching of colloidal ZIF-8 and ZIF-67 crystals. Our work enables uniform reshaping of these porous materials into unprecedented morphologies, including cubic and tetrahedral crystals, and even hollow boxes, by an acid-base reaction and subsequent sequestration of leached metal ions. Etching tests on these ZIFs reveal that etching occurs preferentially in the crystallographic directions richer in metal-ligand bonds; that, along these directions, the etching rate tends to be faster on the crystal surfaces of higher dimensionality; and that the etching can be modulated by adjusting the pH of the etchant solution.
authors.affiliation: ICN2-Institut Catala de Nanociencia i Nanotecnologia, Campus UAB, 08193 Bellaterra, Barcelona (Spain).
authors.forename: Civan
authors.initials: C
authors.lastname: Avci
authors.affiliation: ICN2-Institut Catala de Nanociencia i Nanotecnologia, Campus UAB, 08193 Bellaterra, Barcelona (Spain).
authors.forename: Javier
authors.initials: J
authors.lastname: Ariñez-Soriano
authors.affiliation: ICN2-Institut Catala de Nanociencia i Nanotecnologia, Campus UAB, 08193 Bellaterra, Barcelona (Spain).
authors.forename: Arnau
authors.initials: A
authors.lastname: Carné-Sánchez
authors.affiliation: ICN2-Institut Catala de Nanociencia i Nanotecnologia, Campus UAB, 08193 Bellaterra, Barcelona (Spain).
authors.forename: Vincent
authors.initials: V
authors.lastname: Guillerm
authors.affiliation: ICN2-Institut Catala de Nanociencia i Nanotecnologia, Campus UAB, 08193 Bellaterra, Barcelona (Spain).
authors.forename: Carlos
authors.initials: C
authors.lastname: Carbonell
authors.affiliation: ICN2-Institut Catala de Nanociencia i Nanotecnologia, Campus UAB, 08193 Bellaterra, Barcelona (Spain). inhar.imaz@icn.cat.
authors.forename: Inhar
authors.initials: I
authors.lastname: Imaz
authors.affiliation: ICN2-Institut Catala de Nanociencia i Nanotecnologia, Campus UAB, 08193 Bellaterra, Barcelona (Spain). daniel.maspoch@icn.cat.|Institució Catalana de Recerca i Estudis Avançats (ICREA), 08100 Barcelona (Spain). daniel.maspoch@icn.cat.
authors.forename: Daniel
authors.initials: D
authors.lastname: Maspoch
keywords: anisotropic etching; hollow particles; metal-organic frameworks; porosity; zeolitic-imidazolate frameworks