Delivered by Ingenta to: Purdue University Libraries IP: 185.101.71.41 On: Mon, 06 Jun 2016 18:11:14 Copyright: American Scientific Publishers Copyright © 2010 American Scientific Publishers All rights reserved Printed in the United States of America Journal of Nanoscience and Nanotechnology Vol. 10, 3175–3179, 2010 Autothermal Reforming of Propane Over Ni-Based Hydrotalcite Catalysts Sun-Young Park 1 , Jong-Ho Kim 2 , Dong-Ju Moon 3 , Nam-Cook Park 2 , and Young-Chul Kim 2 ∗ 1 Department of Advanced Chemical Engineering and Center for Functional Nano Fine Chemicals, Chonnam National University, Gwangju 500-757, Korea 2 Faculty of Applied Chemical Engineering and the Research Institute for Catalysis, Chonnam National University, 300 Yongbong-dong, Gwangju, 500-757, Korea 3 Korea Institute of Science and Technology, Hawalgok-dong, Seongbuk-gu, Seoul 136-791, Korea Ni-based hydrotalcite catalysts were investigated for ATR of propane in a fixed-bed flow reactor. The reactions were carried out with a H 2 O/C/O 2 stream ratio of 3/1/0.73 at temperatures ranging from 300 to 700  C. The solvents used in the manufacture of Ni-based catalysts noble metal/Ni/MgAl catalysts or substituted active material were changed in order to decrease the level of catalyst deactivation. The use of a mixture of ethanol and water during the formation of the Pd-Ni/MgAl catalyst produced a higher hydrogen yield than that using water only. In addition, the use of acetone in the synthesis of Ru-Ni/MgAl catalyst produced a higher hydrogen yield than using water only. This shows that the solvents used for the noble metals affect the degree of dispersion and particle size of the nickel and prevented carbon deposition resulting in the enhanced hydrogen selectivity and catalyst activity. Active metals were substituted during the preparation of hydrotalcite catalysts. Among the catalysts prepared with various ratio (Ni:Fe) tested at high temperature, the ratio, Ni:Fe = 75:25, showed best performance. There was less sintering of Ni particles due to substitution of the active metal at the optimal ratio. Keywords: Autothermal Reforming, Hydrogen, Propane, Hydrotalcite. 1. INTRODUCTION Hydrogen energy is has become an important issue for solving environmental problems and acting as a substitute for fossil fuels because it based upon the water or organic matter, and recycled water. In addition, hydrogen can be applied to most industries on account of its high level of energy per gram. For this reason, the hydrogen economy is expected in the future. 1–2 Of the many processes for hydrogen production, the reforming of hydrocarbons has a low manufacturing cost compared with methods using alternative energy. In addition, a variety of catalysts have been investigated. Autothermal reforming (ATR) is a combination of steam reforming and a partial oxidation reaction. It has an advan- tageous route for production and low-energy requirements due to the exothermic and endothermic contributions from propane oxidation and steam reforming, respectively. The reactor improves resistibility for the formation of hot spots and carbon deposits. 4 ∗ Author to whom correspondence should be addressed. Hydrotalcite-like compounds have a memory effect, stability against thermal treatments, larger surface area (100∼300 m 2 /g) and uniform dispersion. Experiments aimed at preparing Ni/MgAl hydrotalcite-like catalysts generally add noble metals. During the manufacture of Ru or Pd modified catalysts, various solvents are used to dissolve the noble metal to decrease the level of carbon deposition and increase the degree of dispersion. 5–7 2. EXPERIMENTAL DETAILS 2.1. MgAl-Hydrotalcite The MgAl HT-like precursor was prepared by mixing Mg 2+ and Al 3+ nitrates at pH = 10.0 at 60∼70  C, follow by aging at 60∼70  C. The resulting product was washed with de-ionized water and dried. The solid was calcined in air. 2.2. Solvents Changing of Noble Metal Doping with Ni was carried out by adopting the memory effect of MgAl HT. A MgAl powder was dipped in an J. Nanosci. Nanotechnol. 2010, Vol. 10, No. 5 1533-4880/2010/10/3175/005 doi:10.1166/jnn.2010.2322 3175