Plasma-catalytic conversion of CO2 into value-added chemicals: Understanding the synergistic effect at low temperatures

Summary form only given. The carbon dioxide issue has recently become the focus of global attention because of the position of CO₂ as the primary greenhouse gas and the implication of its emissions on the problems of climate change and global warming. In the past decade, strategies have largely focused on the development of different technologies for CO₂ capture and storage (CCS). The idea is rather than treating CO₂ as a waste, it can be regarded as a low value raw chemical for the production of value-added fuels and chemicals, finding beneficial ways to “use” in addition to permanently storing the emitted CO₂. However, due to high stability of CO₂ molecule, it is a great challenge to thermally decompose CO₂. High temperatures (>3000 K) are required to get a reasonable CO₂ conversion, incurring a high energy cost.Recently, the combination of non-thermal plasma and catalysis provides an attractive alternative to the conventional catalytic route for the conversion of greenhouse gas into value-added fuels and chemicals because of its unique capability to induce both physical and chemical reactions at low temperatures 1, 2. In this study, a coaxial dielectric barrier discharge (DBD) reactor has been developed for plasma-catalytic conversion of CO₂ into higher value chemicals (e.g., CO and methanol) at low temperatures. Combining DBD with BaTiO₃ and TiO₂ photocatalysts significantly enhances CO₂ conversion and energy efficiency by up to 250%. The synergy of plasma-catalysis for CO₂ conversion can be attributed to both the physical effect induced by the presence of catalysts in the plasma and photocatalytic surface reactions driven by the discharge.