Light driven water oxidation is a key step in artificial photosynthesis, aimed at splitting water into hydrogen and oxygen with sunlight. In such process, the interactions between a photosensitizer (PS) and a water oxidation catalyst (WOC) play a crucial role in the rates of photoinduced electron transfers, determining the overall quantum efficiency of the system. In this work, by means of Small Angle X-ray Scattering (SAXS) we investigate the nature of the aggregates between ruthenium polypyridine photosensitizers (Rubpy and Ru4dend) and a tetraruthenium polyoxometalate (Ru4POM) water oxidation catalyst. Aggregate scattering is confirmed by the strong intensity-increase in the low-q regime, whereas the power law-fit of this region show slopes between −3 and −4, suggesting globular and porous aggregates. Intermolecular PS/WOC distances lower than 3 nm support the observed fast photoinduced electron transfers (<120 ps), however the proximity of the two components in the hybrids is also responsible for fast charge recombination. Approaches for inhibiting such undesired process are discussed.

Ruthenium based photosensitizer/catalyst supramolecular architectures in light driven water oxidation

SYRGIANNIS, ZOIS;NATALI, MIRCO;PRATO, MAURIZIO;
2017-01-01

Abstract

Light driven water oxidation is a key step in artificial photosynthesis, aimed at splitting water into hydrogen and oxygen with sunlight. In such process, the interactions between a photosensitizer (PS) and a water oxidation catalyst (WOC) play a crucial role in the rates of photoinduced electron transfers, determining the overall quantum efficiency of the system. In this work, by means of Small Angle X-ray Scattering (SAXS) we investigate the nature of the aggregates between ruthenium polypyridine photosensitizers (Rubpy and Ru4dend) and a tetraruthenium polyoxometalate (Ru4POM) water oxidation catalyst. Aggregate scattering is confirmed by the strong intensity-increase in the low-q regime, whereas the power law-fit of this region show slopes between −3 and −4, suggesting globular and porous aggregates. Intermolecular PS/WOC distances lower than 3 nm support the observed fast photoinduced electron transfers (<120 ps), however the proximity of the two components in the hybrids is also responsible for fast charge recombination. Approaches for inhibiting such undesired process are discussed.
File in questo prodotto:
File Dimensione Formato  
1-s2.0-S0020169316301621-main.pdf

Accesso chiuso

Tipologia: Documento in Versione Editoriale
Licenza: Digital Rights Management non definito
Dimensione 990.28 kB
Formato Adobe PDF
990.28 kB Adobe PDF   Visualizza/Apri   Richiedi una copia
3904_11368_2892436_EUT.pdf

Open Access dal 23/04/2018

Tipologia: Bozza finale post-referaggio (post-print)
Licenza: Creative commons
Dimensione 924.44 kB
Formato Adobe PDF
924.44 kB Adobe PDF Visualizza/Apri
Pubblicazioni consigliate

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11368/2892436
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 14
  • ???jsp.display-item.citation.isi??? 15
social impact