Regeneratable trinuclear iron-oxo cocatalyst for photocatalytic hydrogen evolution

Abstract

A trinuclear iron-oxo complex has been experimentally confirmed to be a regeneratable cocatalyst for hydrogen evolution from water splitting. This nano-sized trinuclear cluster with a seperated core structure that covalently connected by a central oxygen may show advantages for excellent separation and directional transfer of photogenerated electrons, promising a qualified substitute for noble metal cocatalysts. By combining with polyoxometalate as photocatalyst, the photocatalytic system proved a higher H2 production than with commercial TiO2. In addition, the polyoxometalate accelerated the H2 production efficiency and made the reaction processes observable by the change in solution color. Cyclic experiments for over 40 h proved the stability and regenerability of the cocatalyst. Furthermore, this cluster was 19 times more efficient than equimolar iron salt in H2 evolution. This new attempt of applying multinuclear metal-oxo clusters in photocatalytic H2 evolution may offer novel design strategies and low-cost cocatalyst candidate for enhanced photocatalytic H2 evolution efficiency.