Hofmeister anion effect on the formation of ZIF-8 with tuneable morphologies and textural properties from stoichiometric precursors in aqueous ammonia solution

Abstract

In this report, a series of anions were demonstrated to remarkably affect and promote the formation of ZIF-8 from a stoichiometric molar ratio of precursors in aqueous ammonia solution at room temperature. The requirement of ammonia concentration for the formation of the pure ZIF-8 phase can be readily modulated by the anion. In addition, the anion types and concentrations can effectively promote the formation of the pure ZIF-8 phase with tuneable particle morphologies and textural properties. The anion effect capacity was revealed to be SO₄²⁻ > CH₃COO⁻ > Cl⁻ > Br⁻ > NO₃⁻, which follows the classic Hofmeister anion sequence.