Effects of iron, bismuth, and vanadium oxides on the properties of cordierite ceramics

The effects of iron oxide (10%), bismuth oxide (2.2%), and vanadium oxide (1.6%) admixtures on the physicochemical properties of cordierite ceramics are reported, including the phase composition, surface features, porous structure, and activity in ammonia oxidation. The formation of the cordierite phase is favored by introducing the oxide modifiers, by raising the heat treatment temperature, and by extending the heating time. The introduction of V2O5 affords well-crystallized cordierite with a small specific surface area and a large proportion of macropores. The oxide modifiers markedly enhance the ammonia oxidation activity and nitrogen oxide selectivity of the cordierite ceramics.