The ability of some nanostructured materials to perform as effective heterogeneous\ncatalysts is potentially hindered by the failure of the liquid reactant to effectively wet\nthe solid catalyst surface. In this work, two different chemical reactions, each involving\na change of phase from liquid to gas on a solid catalyst surface, are investigated.\nThe first reaction is the catalyzed decomposition of a H2O2 monopropellant within a\nmicro-chemical reactor chamber, decorated with RuO2 nanorods (NRs). The second\nreaction involves the electrolysis of dilute aqueous solutions of H2SO4 performed\nwith the cathode electrode coated with different densities and sizes of RuO2 NRs. In\nthe catalyzed H2O2 decomposition, the reaction rate is observed to decrease with increasing\ncatalyst surface density because of a failure of the liquid to wet on the catalyst\nsurface. In the electrolysis experiment, however, the reaction rate increased in\nproportion to the surface density of RuO2 NRs. In this case, the electrical bias applied\nto drive the electrolysis reaction also causes an electrostatic force of attraction between\nthe fluid and the NR coated surface, and thus assures effective wetting.
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