Giant iron polyoxometalate that works as a catalyst for water oxidation

A polyoxometalate (POM) cluster [Mo72Fe30O252(CH3COO)(12){Mo2O7(H2O)}(2){H2Mo2O8(H2O)}(H2O)(91)] ca. 150 H2O (catalyst I) has been explored as an efficient light-driven water oxidation catalyst. The photocatalytic experiments were performed with photosensitizer [Ru(bpy)(3)](2+) (bpy = 2,2 '-bipyridine) and blue light similar to 420 nm. The oxygen evolution process was observed at pH 9.0. Catalyst I was recovered after the catalytic cycle. FT-IR and XPS experiments confirmed the stability of the recovered catalyst. The oxygen evolution was detected immediately after the light was switched ON. It was also established that the stable catalyst I could be reused/recycled several times.