Green and rapid preparation of hierarchically porous metal–organic zeolites and simulation of their growth

Abstract

Research on metal–organic zeolites (MOZs) aims to achieve three objectives, namely to enlarge the pore size, reduce energy consumption and enhance the production rate. However, it is very difficult to realize the three at the same time. Herein, an efficient and versatile strategy was developed with an anionic surfactant as the template and a hydroxy double salt (HDS) as the accelerant. Based on the proposed strategy, the rapid preparation of stable hierarchically porous MOZs (HP-MOZs) with tunable porosity under facile conditions was achieved. This proposed method not only introduced mesopores and macropores into conventional MOZs but also realized MOZ fabrication with low power consumption. More importantly, it could simultaneously improve the production rate with drastic reduction in the time required for crystallization of HP-MOZ frameworks. Furthermore, the mechanism underlying the rapid synthesis of HP-MOZs was elaborated for the first time by means of mesoscopic dynamics simulation combined with an in situ experimental technique. The space–time yields (STYs) for the as-synthesized HP-MOZs could be remarkably increased, with a maximal STY as high as 3.20 × 10⁴ kg m⁻³ d⁻¹, which has set a new record. The resulting HP-MOZ materials showed quite excellent sorption properties for CO₂ and CH₄, which are improved by >50% in terms of uptake capacities compared with those of microporous MOZs. The simple, facile and effective synthesis strategy developed in this study may open a new avenue for fabricating a wide variety of HP-MOZs that are expected to be applied on an industrial scale.