| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 46437 | Applied Catalysis B: Environmental | 2012 | 10 Pages |
The activity-stability pattern of ceria-based noble metal (Pt/CeO2) and transition metal-oxide (MnCeOx) catalysts in the wet air oxidation of phenol (CWAO) at different catalyst-to-phenol weight ratio (R, 1–5) was comparatively probed using a stirred batch reactor with continuous oxygen feed (TR, 150 °C; PO2,PO2, 0.9 MPa). Both Pt/CeO2 and MnCeOx systems drive a surface dual-site Langmuir–Hinshelwood (L–H) reaction path enabling higher efficiency, different reaction kinetics and “phenol-total organic carbon” conversion relationships in comparison to homogeneous CWAO catalysts [1]. A simplified reaction scheme based on consecutive adsorption and mineralization steps and the relative kinetic analysis show that the former determines the rate of phenol and TOC removal, while the latter controls the selectivity and rate of catalyst fouling. The MnCeOx system ensures a fast and complete phenol conversion and a TOC removal higher than 80% at any R, while improved adsorption and mineralization functionalities explain a higher resistance to deactivation by fouling than Pt/CeO2 system.
Graphical abstractComparison of the CWAO pattern of the Pt/CeO2 and MnCeOx catalysts at 150 °C and various catalyst-to-phenol weight ratio (R) with that of homogeneous systems [1]: TOC vs. phenol conversion.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► The activity pattern of Pt/CeO2 and MnCeOx systems in the phenol CWAO is addressed. ► Activity pattern is explained by a L–H path based on adsorption and oxidation steps. ► Homogeneous and heterogeneous CWAO processes show diverse phenol-TOC conversion relationships. ► Higher adsorption and oxidation rates explain the better activity of MnCeOx system.
