Enhancement of Activity of Noble Metal Nanoparticles in Oxidative Electrocatalysis through Modification with Mixed-Metal Oxo-Species
We pursue a concept of utilization of hybrid mixed metal (tungsten(VI)/zirconium(IV), tungsten(VI)/titanium(IV), tungsten(VI)/cerium(IV)) oxides as matrices for supporting and activating noble metal nanoparticles (e.g. Pt, Pt-Ru, Pd, Ru or Rh) during electrooxidation of methanol, ethanol, dimethyl ether and formic acid. Remarkable increases of electrocatalytic currents measured under voltammetric and chronoamperometric conditions have been observed. The most likely explanation takes into account possibility of specific interactions of noble metals with transition metal oxide species as well as existence of active hydroxyl groups in the vicinity of catalytic noble metal sites.
The concept of utilization of mixed metal oxide supports to active noble metal catalytic sites will be extended to oxidation of such inert reactants as arsenate(III) and nitrate(III) that of importance to analytical chemistry, namely to electroanalytical determinations of toxic oxoanions. Mechanistic considerations will be provided, and comparison will be made to the behavior of small organic molecules mentioned above.