Zeolitic Imidazolate Framework Membrane with Marked Thermochemical Stability for High-Temperature Catalytic Processes

Abstract

The thermochemical stability of metal organic framework (MOF) membranes is vital for the application in chemical-reaction and -separation processes, but understanding the stability of MOF membranes and structure–property relationships under antagonistic chemical atmosphere is still required. In this work, a supported zeolitic imidazolate framework (ZIF) membrane, ZIF-7/MgO-Al2O3, of unprecedented hydrothermal stability is obtained by a modulation of the acid–base chemistry at the membrane/support interface. The solid/solid interface acidity that has been overlooked in the fields turns out to have paramount inducing effects on the thermochemical stability of ZIF membranes, resulting in the catastrophic acid-catalyzed decomposition of ZIF frameworks at atomic level. The ZIF-7/MgO-Al2O3 of marked thermochemical stability permits the first significant application of MOF membranes for catalytic membrane reactor (MR) in severe and practical process conditions, performing water–gas shift reaction (CO + H2O ↔ CO2 + H2) at considerably high temperatures (473–673 K) and steam concentrations (20–40%). The findings and results provide significant new insights on the property and stability of ZIF membranes with extensive opportunities for thermochemical processes that have been permitted only for the inorganic membranes such as zeolites, palladium, and metal oxides.