Articolo in rivista, 2021, ENG, 10.1016/j.apcata.2020.117917

Tailoring manganese oxide catalysts for the total oxidation of pollutants in gas and liquid phase

Arena F.; Di Chio R.; Palella A.; Spadaro L.; Frusteri L.; Fazio B.; Morandi S.; Martra G.

Department of Engineering, University of Messina, C.da Di Dio, S. Agata, Messina, I-98166, Department of Engineering, University of Messina, C.da Di Dio, I-98166 S. Agata (Messina), Italy, , Italy; CNR-ITAE Institute "Nicola Giordano", Salita S. Lucia 39, S. Lucia, Messina, I-98126, CNR-ITAE Institute "Nicola Giordano", Salita S. Lucia 39, I-98126 S. Lucia (Messina), Italy, , Italy; CNR-IPCF Institute, Viale F. Stagno D'Alcontres 37, S. Agata, Messina, I-98158, CNR-IPCF Institute, Viale F. Stagno D'Alcontres 37, I-98158 S. Agata (Messina), Italy, , Italy; Department of Chemistry and Centre for "Nanostructured Interfaces and Surfaces-NIS", University of Torino, Via P. Giuria 7, Torino, I-10125, Department of Chemistry and Centre for "Nanostructured Interfaces and Surfaces-NIS", University of Torino, Via P. Giuria 7, I-10125 Torino, Italy, , Italy

Bare and ceria-promoted MnO catalysts (0 <= ?<=1) were prepared by redox-precipitation reactions of Mn(VII), Mn(II) and Ce(III) or Ce(IV) precursors in slightly acidic (pH, 4.5) or basic (pH, 8.0) environment to assess genesis, nature, and functionality of surface active sites. Both synthesis protocols yield nanostructured materials with large surface area and exposure of Mn sites, featuring high activity in the CO oxidation and the phenol wet-air-oxidation (CWAO) model reactions (T, 423 K). High oxide dispersion prompts an extensive incorporation of Mn(II) ions into ceria substitutional solid-solution structures, forming oxygen-vacancies with stronger oxidation activity than surface Mn(IV) sites. Basic structure-activity relationships indicate that the superior CO oxidation performance of the pristine ?-MnO system relies on large exposure of very reducible Mn(IV) active sites, while O-adsorption onto Mn(II)/O-vacancy active centres generates very reactive surface oxygen-species boosting the efficiency of composite MnCeO catalysts in the CWAO of phenol.

Applied catalysis. A, General (Print) 610 , pp. 117917-1–117917-10

Keywords

Manganese oxide catalysts, Active sites, CO oxidation, Phenol wet air oxidation (CWAO), Structure-activity relationships, Catalyst design

CNR authors

Frusteri Leone, Fazio Barbara, Spadaro Lorenzo, Palella Alessandra

CNR institutes

IPCF – Istituto per i processi chimico-fisici, ITAE – Istituto di tecnologie avanzate per l'energia "Nicola Giordano"