Wet Air Oxidation of phenol over Pt and Ru catalysts supported on cerium-based oxides: Resistance to fouling and kinetic modelling

• Ce-based supported Pt and Ru catalysts were tested at 160 °C in the CWAO of phenol.
• The key-step is the elimination of deactivating adsorbed compounds.
• Polymer formation is a mild oxidation reaction favoured with high OSC catalysts.
• High dispersions are beneficial to the degradation of fouling molecules.
• An easy-to-employ kinetic model was proposed and validated.

Ceria and doped ceria supported Pt and Ru catalysts were tested at 160 °C in the Catalytic Wet Air Oxidation (CWAO) of phenol. Catalysts were compared in terms of activity, selectivity and resistance towards fouling. The respective influences of metal phase and support were studied. Under the selected operating conditions, 100% phenol conversion could be reached. Contrary to what was expected, improved Oxygen Storage Capacities (OSC) accelerated the accumulation of adsorbed species on the catalyst surface, therefore limiting the catalytic performance. By contrast, high metal dispersions enhanced both the elimination of aqueous organic compounds and the degradation of heavy molecules involved in the catalyst fouling. The progressive decrease in activity induced by carbonaceous deposits could be kinetically modelled using a simple reaction scheme.

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