Redox reactions with colloidal metal oxides. Comparison of radiation-generated and chemically generated RuO2·2H2O

Authors:
  • AHAnthony Harriman
    Anthony Harriman
  • MRMarie-Claude Richoux
    Marie-Claude Richoux
  • PCPaul A. Christensen
    Paul A. Christensen
  • SMShlomo Mosseri
    Shlomo Mosseri
  • PNPedatsur Neta
    Pedatsur Neta
Publisher website
Google Scholar
Abstract
Colloids of RuO2· 2H2O and MnO2 have been produced by chemical and radiolytic methods. The colloids slowly aggregate upon standing in water over several weeks but radiolysis gives much smaller particles. The colloids are active in catalysing water oxidation under chemical and photochemical conditions although there is some corrosion. The chemically formed RuO2· 2H2O colloids are quite efficient catalysts for water reduction to H2 but the radiolytically formed colloids do not promote H2 formation. Colloidal MnO2 is a poor catalyst for both H2 and O2 generation and it tends to aggregate under operating conditions. The RuO2· 2H2O colloids obtained by gamma radiolysis are selective for oxidation processes. They are stable and catalyse O2 formation with high efficiencies. Such materials appear to be the best catalysts available for use in model systems for the photodissociation of water.