Related Experiment Video
Updated: May 30, 2025

Synthesis and Performance Characterizations of Transition Metal Single Atom Catalyst for Electrochemical CO2 Reduction
Published on: April 10, 2018
Mechanisms of CO oxidation on high entropy spinels
Martina Fracchia1,2, Paolo Ghigna1,2, Sara Stolfi1,3
1Dipartimento di Chimica, Università di Pavia, V.le Taramelli 13, I-27100, Pavia, Italy. paolo.ghigna@unipv.it.
Abstract:
The CO oxidation reaction on (Co,Mg,Mn,Ni,Zn)(Al,Co,Cr,Fe,Mn)2O4 and (Cr,Mn,Fe,Co,Ni)3O4 high entropy spinel oxides was studied for what concerns its mechanism by means of operando soft X-ray absorption spectroscopy. In the (Cr,Mn,Fe,Co,Ni)3O4 high entropy spinel, CO oxidation starts at ca. 150 °C, and complete conversion to CO2 is obtained at ca. 300 °C. For the (Co,Mg,Mn,Ni,Zn)(Al,Co,Cr,Fe,Mn)2O4 spinel oxides, in contrast, the reaction starts at ca. 200 °C, and complete conversion needs temperatures of the order of 350 °C. Concerning the reaction mechanism, we found that, in both cases, Mn is the active metal, via the Mn(II)/Mn(III) redox couple. CO is found to adsorb on surface Mn(III) sites and reduces them to Mn(II). The Mn(III) oxidation state is recovered by O2, yielding CO2. All the other transition metals are found to be inactive and act just as spectators. These findings are discussed in the framework of the present knowledge on high entropy oxides.
More Related Videos
Related Concept Videos
Colors and Magnetism
When atoms or molecules absorb light at the proper frequency, their electrons are excited to higher-energy orbitals. For many main group atoms and molecules, the absorbed photons are in the ultraviolet range of the electromagnetic spectrum, which cannot be detected by the human eye. For coordination compounds, the energy difference between the d orbitals often allows photons in the visible range to be absorbed and emitted, which is seen as colors by the human...
Valence Bond Theory
Redox Equilibria: Overview
Electron Transport Chain: Complex III and IV
Oxidation-Reduction Reactions
Introduction to Mechanisms of Enzyme Catalysis

