title: Artificial photosynthesis challenges: water oxidation at nanostructured interfaces.
abstract: Innovative oxygen evolving catalysts, taken from the pool of nanosized, water soluble, molecular metal oxides, the so-called polyoxometalates (POMs), represent an extraordinary opportunity in the field of artificial photosynthesis. These catalysts possess a highly robust, totally inorganic structure, and can provide a unique mimicry of the oxygen evolving center in photosynthetic II enzymes. As a result POMs can effect H₂O oxidation to O₂ with unprecedented efficiency. In particular, the tetra-ruthenium based POM [Ru(IV) ₄(μ-OH)₂(μ-O)₄(H₂O)₄(γ-SiW(10)O(36))₂](10-), Ru₄(POM), displays fast kinetics, electrocatalytic activity powered by carbon nanotubes and exceptionally light-driven performance. A broad perspective is presented herein by addressing the recent progress in the field of metal-oxide nano-clusters as water oxidation catalysts, including colloidal species. Moreover, the shaping of the catalyst environment plays a fundamental role by alleviating the catalyst fatigue and stabilizing competent intermediates, thus responding to what are the formidable thermodynamic and kinetic challenges of water splitting. The design of nano-interfaces with specifically tailored carbon nanostructures and/or polymeric scaffolds opens a vast scenario for tuning electron/proton transfer mechanisms. Therefore innovation is envisaged based on the molecular modification of the hybrid photocatalytic center and of its environment.
authors.affiliation: ITM-CNR and Dipartimento di Scienze Chimiche, Università di Padova, via Marzolo 1, 35131, Padova, Italy.
authors.forename: Mauro
authors.initials: M
authors.lastname: Carraro
authors.forename: Andrea
authors.initials: A
authors.lastname: Sartorel
authors.forename: Francesca Maria
authors.initials: FM
authors.lastname: Toma
authors.forename: Fausto
authors.initials: F
authors.lastname: Puntoriero
authors.forename: Franco
authors.initials: F
authors.lastname: Scandola
authors.forename: Sebastiano
authors.initials: S
authors.lastname: Campagna
authors.forename: Maurizio
authors.initials: M
authors.lastname: Prato
authors.forename: Marcella
authors.initials: M
authors.lastname: Bonchio
mesh_terms: D049329:Nanostructures / Q000737:chemistry*; D037742:Nanotubes, Carbon / Q000737:chemistry; D010084:Oxidation-Reduction; D010788:Photosynthesis; D014867:Water / Q000737:chemistry*
chemical_list: D037742:Nanotubes, Carbon; D014867:Water