Catalytic decomposition of sulfuric acid on silicon carbides for sulfur-based thermochemical water spliting cycles

FUEL 157

Ja Hun Kwak, kwak@pnl.gov1, Yong Wang, yongwang@pnl.gov1, Daniel M. Ginosar, Daniel.Ginosar@inl.gov2, and Lucia M. Petkovic, Lucia.Petkovic@inl.gov2. (1) Institute for Interfacial Catalysis, Pacific Northwest National Laboratory, P.O. Box 999, MS K8-93, Richland, WA 99352, (2) Chemical Sciences, Idaho National Laboratory, P.O. Box 1625, MS 2208, Idaho Falls, ID 83415-2208
The activity of sulfuric acid decomposition catalysts for hydrogen production by thermochemical cycles was investigated at 850oC for 24 hrs on SiC samples synthesized from different precursors. The SiC materials displayed different catalytic activities not correlated with initial surface area. Uniquely, silicon carbide synthesized from diatom showed comparable activity with 0.1%Pt/TiO2, a catalyst under study for the reaction. The 0.1%Pt/TiO2 catalyst demonstrated high initial activity (~ 29 % SO2 yield) but lost activity rapidly with time (~ 13% SO2 yield after 24 hrs). However, the SiC synthesized from diatom sustained catalytic activity over 24 hrs, even showing a slight improvement with time (~ 19% SO2 yield). Despite possessing stable activity, silicon carbides were oxidized during the reaction and lost considerable amount of surface area. TEM and XRD analysis show that the SiO2 formed after 24 hrs reaction had very different morphologies (size, shape, crystallinity, etc) depending on the original SiC.
 

Advances in Hydrogen Production
1:30 PM-5:05 PM, Tuesday, 12 September 2006 Palace -- Marina Room, Oral

Division of Fuel Chemistry

The 232nd ACS National Meeting, San Francisco, CA, September 10-14, 2006