Understanding Effects of Operating Parameters on Plasma Catalytic Nitrogen-Methane Coupling Using Optical Emission Spectroscopy

Plasma-Catalyst Synergy in the One-Pot Nonthermal Plasma-Assisted Synthesis of Aromatics from Methane

“…As depicted in Figure 2, the CH 4 conversion obtained for the DBD environment with no packing decreases as a function of the bulk gas temperature, which we have reported in recent studies. 29 This behavior has also been previously reported in our group for plasma-assisted CH 4 dry reforming, 24 and it can be attributed to a mode transition in the DBD from a filamentary behavior to a more diffusive mode at higher bulk gas temperatures. 30,31 This mode transition is characterized by a change in the shape of the Lissajous plot as the bulk gas temperature is increased, where an oval shape is observed and is characteristic of a diffusive discharge (Figure 3a).…”

“…This transition leads to a decrease in various plasma properties, such as the intensity of the filaments, total and average charge, and filament lifetime, all of which influenced methane activation. 29 Here, we observe low-temperature conversion of methane by plasma activation to form secondary products that (1) aromatize over acid sites in the zeolite and (2) interact with Mo to form Mo-carbide phases. Therefore, controlling the bulk gas temperature is critical in understanding plasma-catalytic interactions for CH 4 activation.…”

“…23 Akintola et al demonstrated that bulk gas temperature inhibits methane conversion as a function of the bulk gas temperature. 29 It was concluded that the increase in the temperature leads to a decrease in gas density, subsequently reducing the resistance of the gas gap prior to ignition. This reduction in gas density with respect to the bulk gas temperature transitions the plasma from a filamentary mode to a more diffusive mode.…”