Concurrent Production of Carbon Monoxide and Manganese(II) Oxide through the Reaction of Carbon Dioxide with Manganese

Abstract

This study introduces the simultaneous production of manganese oxide (MnO (II)) and carbon monoxide (CO) from the reaction of carbon dioxide (CO2) with manganese (Mn) at ambient pressures. The reaction results showed that Mn oxidation in the presence of CO2 creates highly pure MnO (99.4 mol %) and a small portion of another manganese oxide (Mn3O4 (III)) with the evolution of CO. It is striking that the oxidation path of manganese under CO2 environments is totally reverse compared to that under oxygen (O2) environments, and it produces MnO at much lower temperature (around 700 °C) than the temperature (1700 °C) from the O2 oxidation path. The different patterns of Mn oxidation by both CO2 and O2 can arise from the differences in thermodynamic stability and reactivity of CO2 and O2. Additionally, mass spectroscopic measurements revealed that CO generation originates from the CO2 reduction. Above 700 °C, more CO was produced by the reverse Boudouard reaction occurring between the carbon deposited on the manganese oxide surface and CO2. This Mn–CO2 reaction system provides an opportunity for producing more valuable products such as MnO and CO by utilizing the greenhouse gas.