CO2 dissociation in a packed bed DBD reactor: First steps towards a better understanding of plasma catalysis

Abstract

Plasma catalysis is gaining increasing interest for CO2 conversion, but the interaction between the plasma and catalyst is still poorly understood. This is caused by limited systematic materials research, since most works combine a plasma with commercial supported catalysts and packings. In the present paper, we study the influence of specific material and reactor properties, as well as reactor/bead configuration, on the conversion and energy efficiency of CO2 dissociation in a packed bed dielectric barrier discharge (DBD) reactor. Of the various packing materials investigated, BaTiO3 yields the highest conversion and energy efficiency, i.e., 25% and 4.5%.Our results show that, when evaluating the influence of catalysts, the impact of the packing (support) material itself cannot be neglected, since it can largely affect the conversion and energy efficiency. This shows the large potential for further improvement of packed bed plasma reactors for CO2 conversion and other chemical conversion reactions by adjusting both packing (support) properties and catalytically active sites. Moreover, we clearly prove that comparison of results obtained in different reactor setups should be done with care, since there is a large effect of the reactor setup and reactor/bead configuration.

Superlocal chemical reaction equilibrium in low temperature plasma

“…The reactor was chosen because of its large volume, which facilitates diagnostic measurements. Furthermore, the reactor does not require packing with catalyst or inert particles, and thus complicated interactions with the bed, which obfuscate fundamental interpretations of reaction rates, were avoided . It will be demonstrated that the steady state is nominally independent of the initial feed speciation provided the relative amounts of different elements are held constant, and that superlocal equilibrium state is fundamentally different than the local equilibrium state at the background temperature.…”

A review on the recent progress, challenges, and perspectives of atmospheric‐pressure cold plasma for preparation of supported metal catalysts

“…Additionally, the catalysts in the form of particle rather than powder are favored to ensure smooth airflow in the reactor. Capacity of coaxial DBD reactor can be improved by tube array structure, or enlarging the size of inner and outer electrodes to increase the catalyst volume . However, the discharge properties may be altered significantly.…”

Modeling for a Better Understanding of Plasma-Based CO2 Conversion

“…Reactions (4) and (5) yield the dissociation of CO 2 and H 2 O, but the products, CO and OH, will rapidly recombine into CO 2 again (reaction (6)). Moreover, the two H atoms and one O atom formed will also quickly recombine, first into OH (through subsequent reactions (7) and (8)) and subsequently into H 2 O through reaction (9). Thus, overall, there is no net dissociation of CO 2 and H 2 O in this pathway (see overall reaction (10)).…”

“…As our results indicate that a higher dielectric constant constrains the discharge to the contact points of the beads, this may limit the catalyst activation due to the limited catalyst surface area in contact with the discharge, and thus it may have implications for the efficiency of plasma catalytic CO 2 conversion. Indeed, the best results are not always reached for the highest dielectric constant [9,10]. Figure 11 illustrates a typical 3D gas flow pattern (a), as well as the calculated electron density profile (b), in a reverse vortex flow (RVF) GA plasma reactor, also called gliding arc plasmatron (GAP), operating in argon.…”

“…In recent years, there is increasing interest in plasma-based CO 2 conversion [1]. Several types of plasma reactors are being investigated for this purpose, including (packed bed) dielectric barrier discharges (DBDs) [2][3][4][5][6][7][8][9][10], microwave (MW) plasmas [11][12][13], and ns-pulsed [14], spark [15], and gliding arc (GA) [16][17][18][19][20] discharges. Research focuses on pure CO 2 splitting into CO and O 2 , as well as on mixtures of CO 2 with a hydrogen source, such as CH 4 but also H 2 OorH 2 ,to produce value-added chemicals like syngas, hydrocarbons, and oxygenated products.…”