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Titre du Document
A Building Block Approach to Photochemical Water-Splitting Catalysts Based on Layered Niobate Nanosheets
Auteur(s)
COMPTON Owen C. ; MULLET Cory H. ; CHIANG Shirley ; ...
Résumé
We present a modular approach to the synthesis of nanostructured catalysts for photochemical splitting of water into hydrogen and oxygen. The catalysts are built from exfoliated, semiconducting niobate nanosheets derived from the layered perovskite HCa2Nb3O10. The latter is a catalyst for photochemical evolution of hydrogen from water under UV irradiation. After chemical modification with 3-aminopropyltrimethoxysilane (APS), IrO2 or Pt particles can be attached to the nanosheets to produce various two-component nanostructures that were fully characterized with transmission electron microscopy and ultraviolet and infrared spectroscopy. Cyclic voltammetry was used to determine the onset potentials for O2 and H2 evolution. At pH = 14, the observed values are in the range +0.61 to +1.24 V (NHE, water oxidation) and -1.36 to -1.62 V (NHE, water reduction). Under UV irradiation, all catalysts evolve hydrogen from water without any sign of deactivation for 5 h. The highest quantum efficiency of 3.49% is observed for a structure with Pt directly grown onto the nanosheets. No O2 is evolved, which we attribute to the adsorption of O2 to the catalyst surface. For Pt-[HCa2Nb3O10], this process starts to shut down H2 evolution after 9 h of constant irradiation, but the activity can be restored to >60% by evacuating the catalyst dispersion and purging it with Ar. Catalysts assembled from preformed citrate-coated Pt nan
Editeur
American Chemical Society
Identifiant
ISSN : 1932-7447
Source
Journal of physical chemistry. C A. 2008, vol. 112, n° 15, pp. 6202-6208 [7 pages]
Langue
Anglais
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