Boreskov Institute of Catalysis of the Siberian Branch of Russian ...

OP-IV-4REFORMING OF ETHANOL OVER METAL CARBIDES SUPPORTEDBY MULTIWALL CARBON NANOTUBESFrigyes Solymosi, Alexander Széchenyi, Ákos KoósInstitute of Solid State and Radiochemistry, University of Szeged, P.O.Box 168, H-6701Szeged, Hungary, Fax: 00-36-62-420-678; E-mail: fsolym@chem.u-szeged.huAbstract:Carbides (Ni, W, V, Fe and Mo) have been prepared by the reduction and reaction ofpartially reduced oxides with multiwall carbon nanotube and carbon Norit. This way ofpreparation produced carbides in nano size. The formation of carbides was followed by XPS.Metal carbides exhibited different catalytic performances, which are influenced by thepreparation of oxides, by the starting compounds, by the nature of carbon support, and bytheir pretreatment. NiC and Mo 2 C were found to be most effective in the production ofhydrogen.Keywords: H 2 production, ethanol, carbides.1. IntroductionThe production of hydrogen from alcohol, particularly from bioethanol gained anincreasing attention in recent years. Al 2 O 3 -supported noble metals are effective catalysts forthe decomposition of ethanol, but the reaction required high temperatures. Anotherdrawback is the rapid deactivation of the catalysts. In the light of these features, greatefforts are being made: (i) to replace Pt metals with less expensive materials, (ii) tolower the reaction temperature, and (iii) to increase the stability of the catalyst.Potential candidates for the replacement of noble metals are the carbides, which exhibit highcatalytic activity in many reactions, but were hardly applied for the production of hydrogenfrom alcohols. A noteworthy exception is the Mo 2 C, which was found to be active in thedecomposition of ethanol 1 and methanol 2 to generate hydrogen. In the present work weexamine the catalytic performance of various carbides (Ni, V, W, and Fe) in thedecomposition and reforming of ethanol. In order to increase the dispersion of carbides weuse multiwall carbon nanotube (CNT) and activated carbon (Norit) of high surface area assupport materials.2. ExperimentalCatalytic reaction was carried out at 1 atm of pressure in a fixed-bed, continuous flowreactor consisting of a quartz tube (8 mm id) 1,2 . The flow rate was in general 40 ml/min. Thecarrier gas was Ar, the ethanol content of the reacting gas-mixture was ~9.0%. Carbideswere prepared by the reaction of oxides with the surface layer of carbon supports, whichresults in carbides in nano size. The starting compounds for the preparation of carbides were thecorresponding oxides, which were prepared by impregnation of carbon supports into solution of146