Z-scheme reduction of carbon dioxide with visible light using a binuclear metal complex and a semiconductor

A hybrid material that consists of a semiconductor and a binuclear metal complex having a redox photosensitizer and a catalytic unit was employed as a photocatalyst for CO2 reduction under visible light. It was found that this kind of hybrid was capable of reducing CO2 into HCOOH (or CO) according to two-step photoexcitation of the semiconductor and the photosensitizer unit of the metal complex. It was found that semiconductors of TaON, CaTaO2N, C3N4, and Y-Ta oxynitride became active component for this system driven by visible light (λ > 400 nm) in combination with a binuclear Ru(II) complex.