Low-Pressure Methanation of CO₂ Using a Plasma–Catalyst System

Optical emission spectroscopy study in CO2 methanation with plasma

“…Methanation with plasma catalysis has been attracting attention as a method for driving the lower-temperature chemical reaction process. [10][11][12][13][14][15][16][17][18][19] Previous studies reported that plasma catalysis drove the methanation reaction at temperatures more than 100 °C lower than thermal catalysis, resulting in a stable process. 16,18) Optimization of plasma and catalyst conditions should be promoted now.…”

Improving the efficiency of Sabatier reaction through H2O removal with low-pressure plasma catalysis

“…The synergistic effect of the non-equilibrium plasma and catalysts enables CH 4 production at low temperatures. [14][15][16][17][18][19][20][21][22][23][24][25][26][27] Based on our previous studies, assuming that CH 4 is formed with CO as one of the intermediates, the dissociation rate constant K d of CO 2 (K d = 1.53 × 10 -11 cm 3 s −1 ) is related to the rate constant K g of CH 4 formation from CO as K g = K d and a rate-determining step (RDS) exists before the formation of CH 4 from CO. 25) This means that the RDS in the plasma reaction under the current conditions is the dissociation of CO or the hydrogenation of C, which is considered an RDS in the conventional catalytic method. Therefore, it is necessary to improve the efficiency of this part of the reaction and optimize the plasma conditions.…”

“…However, previous studies have shown that when CO 2 methanation is performed with discharge power as a parameter, the CO 2 conversion increases with higher discharge power (higher electron density), but the conversion saturates at approximately 60% owing to the effect of the reverse reaction. 27) Therefore, the suppression of the CO-to-CO 2 formation reaction is an issue for high-throughput CO 2 methanation. Because of its reactivity, the hydroxyl radical OH is an important transient reactive species in plasma chemical processes.…”

Effect of gas flow rate and discharge volume on CO2 methanation with plasma catalysis

“…Chemical reactions using plasma catalysis have attracted attention as a technology that supports low-temperature processes. [15][16][17][18][19][20][21][22][23][24][25][26] The decomposition and excitation of the source gases by electron impact leads to CH 4 generation at lowertemperatures. Some researchers have reported that the process could be promoted at 150 °C, which is 50 °C lower than the conventional process temperature of 200 °C, with a high efficiency.…”

“…15,16,22,25) Although the use of low-pressure plasmas has been relatively understudied, due to their high pumping costs and slow reaction rates, they have several advantages, including: 1. the extended lifetime of the reactive species; 2. the generation of stable plasma; 3. the application of various plasma diagnostic methods. 18,20,21,26) In this study, we report on the results of optimizing the CH 4 generation rate by controlling the gas flow rate and discharge volume, using a low-pressure capacitively coupled plasma (CCP).…”