SO₃ Decomposition catalysts for the production of sulfur dioxide and oxygen for sulfur based thermochemical water splitting cycles

The production of sulfur dioxide (SO₂) and oxygen via a hightemperature (950-1250K) catalytic decomposition of sulfur trioxide (SO₃) is the key reaction in sulfur-based thermochemical water splitting cycles for the production of hydrogen. When coupled with other reactions responsible for regenerating SO₃ and hydrogen generation, hydrogen can be obtained without producing a carbon dioxide byproduct when non fossil energy heat sources, such as heat from a solar or nuclear source, are employed. The Idaho National Laboratory has been exploring catalysts for the SO₃ decomposition reaction. Platinum, platinum group metals (PGM), and metal oxides all display activity for the decomposition reaction, but to different degrees of efficiency and catalyst stability. This paper provides an overview of the Idaho National Laboratory research efforts in the area of catalysts for the SO₃ decomposition reaction.