LAUSR

Zeolites are considered a cornerstone of the modern petroleum and chemical industries, because their human-made synthesis and industrial applications have greatly helped drive the revolutions in petroleum refining and chemical production processes. However, it is widely accepted that the intracrystalline diffusion limitation, which arises from the relatively small micropores of zeolites (<1 nm), substantially limits the performance of zeolite-based catalysts [1]. In particular, when zeolite is used for the conversion of bulky molecules, such as heavy crude oil and biomass, this limitation becomes more evident. In such cases, hierarchical zeolites with intrinsic microporosities and integrated mesoporosities (and/or macroporosities) offer an effective solution to overcome the drawbacks of conventional microporous zeolites in catalytic applications [2–4]. To date, several synthesis strategies have been developed to produce hierarchical zeolites with multimodal pore architectures [5]. Most of these synthesis methods use mesoscale templates to create secondary porosity during the zeolite crystallisation process. Three classes of templating methodologies can be discerned: solid templating, supramolecular templating and indirect templating [5]. Considerable progress has been achieved in this field; nevertheless, this route is still far from being applied practically, because it is a complicated, expensive and environmentally unfriendly process. Moreover, the existing processes used to fabricate zeolites are not green at their sources, as they inevitably involve the use of synthetic aluminiumand silicon-containing chemicals. These chemicals are derived from natural aluminosilicate or silicate minerals through a series of complicated processes [6]. MESOSCALE DEPOLYMERISATIONREORGANISATION STRATEGY