PARTIAL OXIDATION OF METHANE TO CO AND H-2 OVER NICKEL AND OR COBALT CONTAINING ZRO2, THO2, UO2, TIO2 AND SIO2 CATALYSTS/

The influence of different metal oxide supports (i.e. ZrO2, ThO2, UO2, TiO2 and SiO2) on the performance of Ni- and/or Go-containing catalys ts [Ni and/or Co/MO2 mole ratio (where M = Zr, Th, U, Ti or Si) = 1.0] in the oxidative methane-to-syngas conversion at very low contact tim e (GHSV = 5.2 x 10(5) cm(3) g(-1) h(-1) at STP) has been investigated. The nickel-containing ZrO2, ThO2 and UO2 catalysts (with or without p re-reduction by hydrogen at 500 degrees C) showed good performance in the process; the order of their performance is NiO-ThO2 > NiO-UO2 > Ni O-ZrO2. The NiO-TiO2 showed appreciable catalytic activity only after its reduction at 800 degrees C. However, this catalyst and the NiO-SiO 2 catalyst showed poor performance in the process. These two catalysts are also deactivated very fast, mostly due to sintering of Ni and/or formation of catalytically inactive binary metal oxide phases by solid -solid reaction at the high catalyst calcination and/or catalytic reac tion temperature. Although the Ni-containing ThO2, UO2 and ZrO2 cataly sts showed good performance, carbon deposition on them during the proc ess is fast. However, because of the addition of cobalt to these catal ysts (with Co/Ni = 1.0), the rate of carbon deposition on them in the process is drastically reduced. This Co addition however resulted in a significant decrease in both the conversion and selectivity; the decr ease in the selectivity was small. (C) 1998 Published by Elsevier Scie nce Ltd. All rights reserved.