In-Situ Chemical Trapping of Oxygen in the Splitting of Carbon Dioxide by Plasma

A crucial step in the plasma splitting of carbon dioxide is the separation of the conversion products, and this is not straightforward, especially for separating O2 from CO2 and CO. In this work the trapping of atomic oxygen by adding a hydrogen source, which enhances the chemical conversion into water, is demonstrated. The experimental and modelling results show that by adding 3% of H2 and 2% of CH4 most of the oxygen can be trapped at a CO2 conversion of ±2.5%. The identified products formed by the addition of CH4 or H2 are mainly H2O and in the case of CH4 also H2. Adding a hydrogen source thus leads to the removal of O2, leaving behind a gas mixture that can be more easily separated.