Catalysis Today, Vol.268, 29-36, 2016
Catalytic activity of LiZr2(PO4)(3) nasicon-type phosphates in ethanol conversion process in conventional and membrane reactors
In this paper synthesis and catalytic properties of new catalysts based on double lithium-zirconium phosphate (LiZr2(PO4)(3)) with monoclinic NASICON-type structure, doped by indium, niobium and molybdenum are discussed. The obtained samples with particle size of 50-300 nm were characterized by X-ray diffraction, scanning electron microscopy and X-ray microanalysis. The synthesized samples exhibit catalytic activity in the dehydration and dehydrogenation reactions of ethanol conversion. The main products were acetaldehyde, diethyl ether, hydrogen, C-2- and C-4-hydrocarbons. Indium- and molibdenum-doped samples were characterized by high activity in dehydrogenation processes, while niobium-doped was more active in dehydration processes. The highest selectivity in diethyl ether formation was achieved for LiZr2(PO4)(3) and Nb-doped samples (90 and 60% at 300 degrees C). The highest hydrogen yield (up to 60%) was obtained with the use of In-doped catalyst. LiZr2(PO4)(3) and Mo-doped samples are also noticeable for high C-4-hydrocarbons formation, selectivity to which reaches 60% at 390 degrees C. Use of a 100% hydrogen selective palladium-ruthenium alloy membrane increases hydrogen yield by 20%. (C) 2016 Elsevier B.V. All rights reserved.