Electron- and Energy-Transfer Processes in a Photocatalytic System Based on an Ir(III)-Photosensitizer and an Iron Catalyst

摘要: The reaction pathways of bis-(2-phenylpyridinato-)(2,2′-bipyridine)iridium(III)hexafluorophosphate [Ir(ppy)2(bpy)]PF6 within a photocatalytic water reduction system for hydrogen generation based on an iron-catalyst were investigated by employing time-resolved photoluminescence spectroscopy and time-dependent density functional theory. Electron transfer (ET) from the sacrificial reagent to photoexcited Ir complex has surprisingly low probability 0.4% per collision. Hence, this step limits efficiency overall system. calculations show that ET takes place only specific encounter geometries. At same time, presence represents energy loss channel due triplet–triplet Dexter type. This is kept small employed concentration ratios, thus favoring reductive necessary reduction. elucidated mechanisms underline further need improve sun light’s pathway catalyst...