G. Di Carlo

Heterogeneous catalytic degradation of phenolic substrates: Catalysts activity

This review article explored the catalytic degradation of phenol and some phenols derivates by means of advanced oxidation processes (AOPs). Among them, only the heterogeneous catalyzed processes based on catalytic wet peroxide oxidation, catalytic ozonation and catalytic wet oxidation were reviewed. Also selected recent examples about heterogeneous photocatalytic AOPs will be presented. In details, the present review contains: (i) data concerning catalytic wet peroxide oxidation of phenolic compounds over metal-exchanged zeolites, hydrotalcites, metal-exchanged clays and resins. (ii) Use of cobalt-based catalysts, hydrotalcite-like compounds, active carbons in the catalytic ozonation process. (iii) Activity of transition metal oxides, active carbons and supported noble metals catalysts in the catalytic wet oxidation of phenol and acetic acid. The most relevant results in terms of catalytic activity for each class of catalysts were reported.

Supported Co3O4-CeO2 monoliths: effect of preparation method and Pd-Pt promotion on the CO/CH4 oxidation activity

Abstract Two structured composite oxides, Co3O4(30wt%)-CeO2(70wt%), have been prepared by washcoating commercial cordierite monoliths with a CeO2-γAl2O3 layer, on which the active phase Co3O4-CeO2 was added through two different methods: dip-coating from a suspension containing the preformed active oxide or impregnation with a solution of the cobalt and cerium precursors. Morphological characterizations of the monoliths have been performed by BET, and SEM-EDAX analyses. Electronic and reduction properties have been evaluated by XPS and H2-TPR, respectively. The effect of the preparation method has been investigated in the catalytic oxidation of CO, whereas the promotion by a low content of Pd-Pt has been evaluated in combined CO-CH4 oxidation tests. Four successive CO oxidation cycles performed over the structured Co3O4-CeO2 indicate that the best performing sample is the monolith prepared by dip-coating, whereas that one obtained by impregnation method manifests a certain deactivation upon two consecutive cycles. Accordingly, XPS spectra are consistent with the presence of the active phase CO3O4 in the former, while Co2+ has been identified as the main species in the latter sample.