Catalytic activity of LiZr2(PO4)3 nasicon-type phosphates in ethanol conversion process in conventional and membrane reactors

• NASICON phosphates performed activity in dehydration and dehydrogenation processes.
• Nb-doped sample showed best dehydration properties.
• In- and Mo-doped samples showed best dehydrogenation activity.
• In-doped sample exhibits the best hydrogen performance.
• Use of Pd/Ru membrane allows to increase hydrogen yield by 20%.

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, C2- and C4-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 °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 C4-hydrocarbons formation, selectivity to which reaches 60% at 390 °C. Use of a 100% hydrogen selective palladium-ruthenium alloy membrane increases hydrogen yield by 20%.

Figure optionsDownload high-quality image (132 K)Download as PowerPoint slide