Review of Plasma-Assisted Catalysis for Selective Generation of Oxygenates from CO2 and CH4

The co-conversion of CO2 and CH4 into oxygenates with nonthermal plasma is attracting considerable interest, principally because this approach can overcome thermodynamic limitations and enables operation under mild conditions. However, plasma must be coupled with appropriate catalysts in order to achieve satisfactory oxygenate selectivities. In this article, the mechanisms underlying plasma-catalytic CO2 + CH4 conversion to three different types of oxygenates (CH3OH, HCHO, and CH3COOH) are discussed along the scales of reaction time (ns to ms) and dimension (nm to mm). Particular emphasis is given to the synergy between plasma-phase and surface reactions. In addition, typical materials (both catalytic and noncatalytic) and experimental setups that can affect the selectivities of oxygenated products are also highlighted.