Coumarin–Ir(III) Complex Anchored on Polymer Film as Photosensitizer for Efficient, Long-Term Photocatalytic Hydrogen Evolution

Abstract

A novel photosensitizer hybrid film (Ir(cumr)2(dabpy)+@NWF-g-MAH) has been designed and synthesized by anchoring a coumarin–Ir(III) complex on a polymer substrate. Photocatalytic tests show that Ir(cumr)2(dabpy)+@NWF-g-MAH displays a long lifetime of over 650 h under visible-light irradiation. The hydrogen evolution efficiency of Ir(cumr)2(dabpy)+@NWF-g-MAH is nearly 25 times higher than that of [Ir(ppy)2(dabpy)]+@NWF-g-MAH in 100 h, and optimizing the average concentration of Ir(cumr)2(dabpy)+@NWF-g-MAH in the hydrogen evolution system improves the hydrogen evolution amount to 12 790 μmol m–2. This photocatalytic system achieves the best synergy of hydrogen evolution efficiency and lifetime so far. The high performance is derived from the sterically bulky substrate effectively inhibiting the photodegradation of the photosensitizer and the coumarin group with strong visible-light absorption in the visible region. This work provides a novel direction for developing a durable and efficient Ir(III) complex for photocatalytic application.