Impact of Argon in Reforming of (CH4 + CO2) in Surface Dielectric Barrier Discharge Reactor to Produce Syngas and Liquid Fuels

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

“…These discrepancies mainly result from the various reactor configurations and experimental conditions used in different studies, both of which may affect the yield of oxygenates significantly. In this section, we focus on the development of temperature-controlled plasma reactors and their applications for oxygenate production. ,, In addition, the involvement of different additives (e.g., dielectric materials, noble gases, , and water , ) in the reactions is discussed. The combination of tailored reactors, appropriate catalysts, and optimized operating conditions may be used to tune the reactions on catalyst surfaces and in plasma afterglows, which can synergize to achieve high selectivities toward desirable oxygenates.…”

“…Similar to the case of dielectric packing, noble gases (e.g., Ar and He) in CO 2 + CH 4 plasma both provide inert dilution and may also accelerate the reactions. Due to the relatively low breakdown potential of Ar and He, these gases may increase the density of microdischarges and electrons in plasma, improving the energy efficiency. ,, The noble gases can also act as third-body molecules and engage in charge transfer with CO 2 and CH 4 , ,, improving the conversion of CO 2 and CH 4 . Consequently, even though the selectivity to and distribution of oxygenated products may not be significantly affected by the introduction of Ar or He, , the oxygenate yields may increase.…”

“…Due to the relatively low breakdown potential of Ar and He, these gases may increase the density of microdischarges and electrons in plasma, improving the energy efficiency. ,, The noble gases can also act as third-body molecules and engage in charge transfer with CO 2 and CH 4 , ,, improving the conversion of CO 2 and CH 4 . Consequently, even though the selectivity to and distribution of oxygenated products may not be significantly affected by the introduction of Ar or He, , the oxygenate yields may increase. Furthermore, the noble gases can also affect the surface reactions.…”

“…In the absence of the primary electron-mediated excitations that occur in the ionized gas, the plasma-excited species de-excite and participate in secondary reactions to form stable products within 1 ms . Typical oxygenated products produced in the afterglows of CO 2 + CH 4 plasmas are methanol (CH 3 OH), formaldehyde (HCHO), and acetic acid (CH 3 COOH), ,,,− among others. After generation, these oxygenates may be carried away by the gas flow and contribute to the overall oxygenate yields.…”

“…The nonequilibrium ionized gas consists of electrons at high thermal velocity (10 4 –10 5 K, 1–10 eV) and more massive excited/ionized species at low temperatures. The high-energy electrons can activate stable CO 2 and CH 4 molecules at low bulk gas temperature and without external heating. − Accordingly, NTP has been reported to induce the formation of oxygenates from CO 2 and CH 4 . − …”