Homogeneous Light-Driven Water Oxidation Catalyzed by a Tetraruthenium Complex with All Inorganic Ligands

摘要

Providing renewable pollution-free fuels is one of the most important scientific challenges of the 21st century, and in this context, the direct, efficient, sustained sunlight-driven splitting of water into H_2 and O_2 remains one of the most desirable targets. Development of O_2 evolution/H_2O oxidation catalysts (WOCs) in artifical photosynthesis (AP) schemes [comprising coupled visible-light photosensitizers, H_2 evolution catalysts (HECs), and WOCs] has frequently been success-limiting, despite significant progress on heterogeneous and homogeneous WOCs. Recently, H_2O oxidation by [Ru(bpy)_3]~(3+) (eq 1)~(14) and Ce(Ⅳ)~(15) catalyzed by the tetraruthenium polyoxometalate complex [{Ru_4O_4(OH)_2(H_2O)_4}-(γ-SiW_(10)O_(36)))_2]~(10-) (1) has been reported. This complex exhibits the stability advantages of heterogeneous catalysts with the tunability and other advantages of homogeneous catalysts. In this work, we demonstrate that 1 catalyzes efficient water oxidation in a totally homogeneous visible-light-driven AP system at neutral (physiological) pH (Scheme 1).