Growth of uniform layers of nanosized zeolites on three-dimensional ordered macroporous carbon: Synthesis, characterization, and catalytic evaluation.

摘要

In this study the synthesis of a hybrid catalyst composed of three-dimensionally ordered macroporous carbon coated with a hydrothermally grown layer of nano-crystalline zeolite particles is proposed. The successful synthesis of such a catalyst will be followed by various physicochemical methods such as scanning electron microscopy, solid-state 27Al-NMR, powder X-ray diffraction, surface area measurement, and elemental analysis of the solid catalyst. The catalyst will then be subjected to test reactions involving large guest molecules, specifically the degradation reaction of high density polyethylene (HDPE). The structure of the proposed system is expected to provide greater access to the large external surface area of acidic zeolite, thereby increasing the rate of the initial and limiting step encountered in the cracking of large polymer molecules. Moreover, the large macropores are expected to lead to the reduction in the contact time between the catalyst and the organic substrate, which could probably reduce the rate of deactivation of the external surface of the catalyst by coke; the formation of which could be the result of over-cracking of the hydrocarbon reaction-intermediates on the surface of the catalyst.