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TiO2-Modified Pd/SiO2 for Catalytic Hydrodeoxygenation of Guaiacol Mohong Lu, Jie Zhu, Mingshi Li, Yuhua Shan, Mingyang He, and Chunshan Song Energy Fuels, Just Accepted Manuscript • DOI: 10.1021/acs.energyfuels.6b00787 • Publication Date (Web): 20 Jul 2016 Downloaded from http://pubs.acs.org on July 27, 2016
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Energy & Fuels
Manuscript ID: ef-2016-00787e.R1
TiO2-Modified Pd/SiO2 for Catalytic Hydrodeoxygenation of Guaiacol Mohong Lu†,‡, Jie Zhu†, Mingshi Li†, Yuhua Shan†，Mingyang He† and Chunshan Song‡,* †
Jiangsu Key Laboratory of Advanced Catalytic Materials and Technology, and
Advanced Catalysis and Green Manufacturing Collaborative Innovation Center, Changzhou University, Changzhou, Jiangsu, 213164, PR China ‡
Clean Fuels and Catalysis Program, EMS Energy Institute, Department of Energy &
Mineral Engineering and Department of Chemical Engineering, Pennsylvania State University, 209 Academic Projects Building, University Park, PA, 16802, USA
*Corresponding author: Professor Chunshan Song Tel: +1-814-863-4466 E-mail:
[email protected] Abstract TiO2 modified Pd/SiO2 catalysts (TixPd/SiO2) have been prepared using wet
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impregnation and characterized with N2 adsorption, XRD, TEM and TPR. Their catalytic performance was examined for hydrodeoxygenation (HDO) of guaiacol as a model component of bio-oil. Smaller Pd particle size was obtained by the addition of TiO2, which may contribute to the high conversion of guaiacol on TixPd/SiO2. Strong interaction between TiO2 and Pd occurred when the catalysts were reduced with H2 at 500
o
C. TiOx covered on Pd particles can coordinate the oxygen atom in
hydrogenation intermediates and activate the C-O bond that could contribute to the significantly enhanced deoxygenation activity. The results suggest that the catalytic HDO proceeds through hydrogenation of the benzene ring of guaiacol on Pd sites to form 2-methoxycyclohexanol, followed by deoxygenation on the sites at reduced TiOx–Pd interface to generate cyclohexane. Keywords: Titania, Palladium, Guaiacol, Hydrodeoxygenation (HDO), Strong interaction
1. Introduction The progressive depletion of fossil fuels requires a gradual phase in of alternative
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Energy & Fuels
sources to fill in the gap between energy supply and demand. Biomass has received increasing attention during the last decade as a renewable and sustainable source of liquid fuels. In general, biomass can be converted into bio-oils by fast pyrolysis or by liquefaction processes [1, 2.]. Unfortunately it is not practical to use bio-oils as a transport fuel due to the high oxygen content, high viscosity, corrosive effect, low calorific value and low chemical stability [3]. Therefore catalytic treatment is necessary to upgrade the bio-oils. One attractive upgrading option is catalytic hydrodeoxygenation (HDO). HDO at moderate temperatures under hydrogen pressure with a heterogeneous catalyst [4] can be employed for the removal of oxygen without unnecessary loss of carbon. Catalyst requirements for bio-oil upgrading processes are different from those for conventional refinery streams due to differences in feed composition, thermal stability and physico-chemical properties. Conventional hydrodesulfurization (HDS) and hydrodenitrogenation (HDN) catalysts such as sulphided CoMo and NiMo have been employed in catalytic HDO of bio-oils in most previous studies [5-9]. Unfortunately the low content of sulfur (typically
