The photoinduced hydrogen evolution reaction (HER) by decamethylruthenocene, Cp2RuII (Cp=C5Me5), is reported. The use of a metallocene to photoproduce hydrogen is presented as an alternative strategy to reduce protons without involving an additional photosensitizer. The mechanism was investigated by (spectro)electrochemical and spectroscopic (UV/Vis and 1H NMR) measurements. The photoactivated hydride involved was characterized spectroscopically and the resulting [Cp2*RuIII]+ species was electrochemically regenerated in situ on a fluorinated tin oxide electrode surface. A promising internal quantum yield of 25 % was obtained. Optimal experimental conditions— especially the use of weakly coordinating solvent and counterions—are discussed.
Michael Graetzel, Shaik Mohammed Zakeeruddin, David Lyndon Emsley, Ursula Röthlisberger, Jacques-Edouard Moser, Jovana Milic, Pascal Alexander Schouwink, Marko Mladenovic, Dominik Józef Kubicki, Paramvir Ahlawat, Aditya Mishra, George Cameron Fish, Masaud Hassan S Almalki, Marco Alejandro Ruiz Preciado, Farzaneh Jahanbakhshi, Vincent Henri Guillaume Dufoulon, Thomas Schneeberger