Giant iron polyoxometalate that works as a catalyst for water oxidation

Abstract

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 ∼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.