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

OP-V-18CATALYTIC PARTIAL OXIDATION OF METHANE TO SYNTHESISGAS OVER CORUNDUM SUPPORTED MIXED OXIDES:TAP STUDIESElena L. Gubanova a,b , Vladislav A. Sadykov b , Andre C. van Veen a , Claude Mirodatos aa Institut de Recherches sur la Catalyse et l’Environnement de Lyon – UMR 5256 (CNRS /Université Claude Bernard Lyon1), 2 avenue Albert Einstein, 69626 Villeurbanne Cedex,Franceb Boreskov Institute of Catalysis SB RAS, Pr. Lavrientieva, 5, 630090, Novosibirsk, RussiaFax: +7 (383) 330-96-87, e-mail: gubanova@catalysis.nsk.suIntroductionThe catalytic partial oxidation of methane is a potential energy efficient alternative to thecapital intensive syngas generation by steam reforming [1]. Synthesis gas formation frommethane may involve two routes depending on the nature and state of the catalyst, a totaloxidation – reforming route or a direct generation, i.e. literal partial oxidation [2,3]. Using theTAP technique with short contact time and negligible thermal effect is one of the mostpromising ways to obtain mechanistic information enabling to conclude on the impact of theoxidation state. The catalyst performance in primary synthesis gas formation is probed, whilethis presents a major difficulty for the very fast oxidation steps at atmospheric pressure. Thepresent study outlines the development of suitable experimental strategies for exploring thesyngas generation over the concerned catalysts with the TAP technique.ExperimentalThe preparation of the fluorite type mixed oxide support involves an adapted Pechiniroute [4]. Monolithic substrates were separate triangular channels of α-Al 2 O 3 monoliths.Coating with the complex mixed oxides Pr 0.3 Ce 0.35 Zr 0.35 O x and Gd 0.3 Ce 0.35 Zr 0.35 O x ,respectively, was accomplished by the peptization method. Pt (1.4 wt.%) was deposited fromH 2 PtCl 6 solution by incipient wetness impregnation followed by drying and calcination at900°C in air. A high temperature TAP reactor was charged with 10mm of the catalyst channelsandwiched between inert quartz sections. Prior to experiments samples were heated to 800°Cand pulses of an O 2 / Ar mixture were introduced to remove residual carbon. The catalyticperformance was estimated at 700°C using pulses of O 2 /Ar and CH 4 /Ar mixtures, both in amolar ratio of 1:1. Pulse intensities of oxygen and methane were set to inject twice as much ofmethane than oxygen using pulse sizes of 4.1·10 15 – 6.8·10 15 molecules per pulse. Pulseresponse detection at characteristic masses and wider scanning for TPD experiments wereaccomplished with a UTI quadruple mass-spectrometer. Conditioning the catalyst to a quasistationary operation proceeded via repeated cyclic oxygen/methane pulsing («working state»),202