Catalytic decomposition of sulfuric acid for thermochemical water splitting processes

The Idaho National Engineering and Environmental Laboratory (INEEL) is currently exploring the limitations of the sulfuric acid decomposition catalyst for the purpose of developing highly active, stable catalysts for a high-temperature catalytic sulfuric acid decomposition reaction step. An overview of the INEEL nuclear hydrogen project was presented, focusing on the sulfuric acid catalytic decomposition studies. To examine catalyst activity and stability, a high-temperature sulfuric acid decomposition reaction system was constructed. The system consists of a sulfuric acid pumping section, a high-temperature SO₃ generation zone, a high-temperature catalytic reaction zone, and a product collection section. Results were presented for three catalysts, i.e., Pt/Al₂O₃, Pt/TiO₂, and Pt/ZrO₂, with Pt loadings ranging from 0.1 to 1 wt %. Preliminary results exploring the Pt/Al₂O₃ catalyst between 800° and 850°C showed that sulfuric acid conversions approaching 65% could be achieved; however, the catalyst was not stable and lost a significant level of activity over a 6 hr period. This is an abstract of a paper presented at the 3rd Topical Conference on Fuel Cell Technology at the 2004 AIChE National Spring Meeting (New Orleans, LA, 4/25-29/2004).