Co/MCM41 catalyst in the COProx reaction prepared by supercritical CO2 reactive deposition

ASPROMONTE, SOLEDAD; MIZRAHI, MARTIN; ALONSO, ESTHER; RAMALLO LOPEZ, JOSE; BOIX, ALICIA V.

MICROPOROUS AND MESOPOROUS MATERIALS

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2017 vol. 239 p. 147 - 157

1387-1811

Co/MCM41 catalyst with 4.3 wt. % Co (Co/sc) has been prepared by supercritical CO2reactive deposition (?scfrd?) and characterized by different physicochemical techniques.This synthesized method was compared with others conventional methodologies suchas template-ion exchanged (Co/tie) and incipient wet impregnation (Co/iwi) with similarcobalt content. All the samples were studied as catalysts on the CO total oxidation(COTox) and preferential oxidation of CO on H2-rich streams (COProx). Incorporatingcobalt with supercritical CO2 leads to a catalyst which produces values of CO conversionsimilar to those obtained by conventional methods such as incipient wetnessimpregnation (Co/iwi) or template-ion exchanged (Co/tie). It has been possible toidentify different cobalt species present in catalysts depending on their synthesismethods by Temperature-Programmed Reduction (TPR), X-ray Photoelectronic (XPS),Laser Raman (LRS) and X-ray Absorption (XANES/EXAFS) spectroscopic studies. Allsamples containing a main cobalt species of cobalt (II) coordinated with Si tetrahedralsites form part of mesoporous structure and lesser extent, cobalt orthosilicate on thesurface. In addition, Co3O4 species dispersed over the MCM41 support were detectedfor the Co/iwi and Co/sc catalysts.Thus, the combination of Co3O4 nanoparticles and Co(II) sites interacting with thesiliceous structure, highly dispersed on the surface and inside the mesoporous supportobtained by the ?scfrd? method resulted in a more active and selective catalyst for theCOProx reaction