In Situ Raman Spectroscopic Study of Species in Co-MnCeOx Catalysts under COPrOx Reaction Conditions

GOMEZ, LETICIA; MUNERA, JOHN; BOIX, ALICIA V.

INDUSTRIAL & ENGINEERING CHEMICAL RESEARCH

AMER CHEMICAL SOC

Lugar: Washington; Año: 2021

0888-5885

: This work is focused on the study of Co-MnCeOxcatalysts by in situ Raman spectroscopy, under COPrOx conditions,and aims to establish a correlation with the catalytic results ofdifferent catalytic formulations. Through XRD, the catalystsstructures were explored, and the oxidation states and relativeconcentrations of surface species were analyzed by XPS. Catalystswere prepared with Co (10 wt %) and different Mn concentrations.The more active catalyst contains 2.5 wt % of Mn and Co/Ce ≈ 1(CO conversion 99.5%, 150−180 °C). The Co-Mn2.5Ce catalyst iscomposed of Co3O4 spinel, Mn inserted in the CeO2 lattice, andprobably MnOx dispersed, which remains stable up to 250 °C underreaction conditions. XRD results confirm the crystalline structure ofCo3O4 spinel; however, there was no evidence of crystalline phases of MnOx oxides. A lower lattice parameter suggests the insertionof Mnn+ ions in the ceria framework. The catalytic surface is composed of Co3+-Co2+ belonging to Co3O4 and Ce4+ of ceria andMn4+-Mn3+ species.