Catalytic Wet Air Oxidation (CWAO) of Phenol in a Fixed Bed Reactor Using Supported Ru and Ru‐Au Catalysts: Effect of Gold and Ce Loading.

Catalysts of Ru and Ru−Au prepared by the wet impregnation and Deposition‐Precipitation methods supported on ZrO2 modified by CeO2(10 and 20 wt%) synthetized by sol‐gel method, in order to study Au and CeO2 addition effect in the catalytic wet air oxidation of phenol, carried out in an automatized continuous fixed‐bed reactor using oxygen as an oxidizing source. Characterizations of the catalysts were made by X‐ray Diffraction (XRD), Specific Surface Area (BET), X‐ray Photoelectron Spectroscopy (XPS), Transmission Electronic Microscopy (TEM), Scanning Electronic Microscopy (SEM), Ultraviolet–visible Spectroscopy (UV‐vis) and Temperature Programmed Desorption of Ammonia (NH3‐TPD). The effect of Au is reflected in the selectivity to CO2 of the catalysts Ru‐ZrO2 and Ru−Au‐ZrO2 with the increase in selectivity from 89 to 95% related to the increase in acidity which increases from 70 to 102 (μmol of NH3/ gCat). Ce loading effect in this case was important to the enhance the CO2 selectivity explained by the formation of Ce4+‐O2−‐M that could favor the oxygen transfer between the catalyst surface and the adsorbed species by a redox mechanism. This study highlights the importance of the CWAO process for pollutants such as phenol at high concentrations in continuous reactors using catalysts, that increase the selectivity towards CO2 (complete mineralization) reaching the 100% for Ru/ZrO2‐CeO2 20 wt%, Ru−Au/ZrO2‐CeO2 10 wt% and Ru/ZrO2‐CeO2 20 wt% catalysts studied and the removal of the pollutant from the effluent, which in our case, reached 64.6% with the monometallic catalyst Ru/ZrO2‐CeO210 wt%. [ABSTRACT FROM AUTHOR]