CO₂ Reduction by Multiple Low-Energy Electric Discharges in a Microstructured Reactor: Experiments and Modeling

Abstract

The simple, robust, and energy-efficient reduction of CO2 to useful products is a significant goal of modern chemistry and chemical engineering. In this study, a novel CO2 reduction process was introduced by employing multiple low energy non-thermal electric glow discharges at the microscale. The process is neither dependent on limited lifetime catalysts nor consumable chemicals, enabling continuous operation over long periods, and operates at atmospheric pressure and temperature, thus simplifying process implementation. The influence of three parameters on the conversion of CO2 within the active volume and energy efficiency was studied, namely, the relative operational regimes on the V–I curve, the residence time of the reactant gas mixture in the plasma region, and the CO2 to water vapor molar ratio. High energy efficiencies of 80–95% and a CO2 conversion of 70–80% can be achieved in the active volume. A mathematical model reflecting geometry and flow conditions inside the microreactor was developed to simulate the chemical reaction process. Through an optimization process, the mathematical model parameters were determined to fit the experimental data and predict primary reaction constants for CO2 reduction.

Enhancing CO2 Absorption with Compact Multiflow Absorber: Evaluation of Operational Factors

“…14 Packed towers are susceptible to plugging and have high capital and operating costs due to the packing. 15 Additionally, many researchers have reported that increasing monoethanolamine (MEA) concentrations increased overall gas side mass transfer coefficient (K Gα ). 16 Due to the high viscosity and corrosivity of MEA, high MEA concentrations are avoided in packed towers.…”

Spark Discharge Plasma-Enabled CO2 Conversion Sustained by a Compact, Energy-Efficient, and Low-Cost Power Supply

“…It has been discovered that increasing SEI could favorably impact conversion rates but may decrease energy efficiency . Others have also sought reactor improvements such as using electrode arrays for efficiency enhancement or introducing magnetic fields into the discharge manipulation …”

“…It has been discovered that increasing SEI could favorably impact conversion rates but may decrease energy efficiency. 31 Others have also sought reactor improvements such as using electrode arrays for efficiency enhance-ment 32 or introducing magnetic fields into the discharge manipulation. 33 However, few have addressed the cost control of the plasma power supplies as well as general principles regarding the reactor design.…”

Microplasma characteristics of direct-current atmospheric pressure glow discharge in dependence of gap distance and discharge current

“…Additionally, the microplasma at atmospheric pressure can generate a higher electron density, excited species density and electron energy while maintaining low reactant temperatures, which can be used for surface treatment without material overheat and can also selectively and with high energetic efficiency realize chemical transformations. Meanwhile, the generation of large-area microplasma at atmospheric pressure can be realized by the microelectrode arrays, which is hardly realized in large gap [8][9][10]. Therefore, microplasma at atmospheric pressure is very popular in the microsystems and portable devices, especially in the field of the medical treatment [7], surface modifications [11,12], sensing application [13,14], nanomaterials synthesis [15], CO 2 reduction [9,16], etc, because of the reduced dimensions, the absence of heat damage, a highly reactive environment and an implementable large-area discharges.…”

“…Meanwhile, the generation of large-area microplasma at atmospheric pressure can be realized by the microelectrode arrays, which is hardly realized in large gap [8][9][10]. Therefore, microplasma at atmospheric pressure is very popular in the microsystems and portable devices, especially in the field of the medical treatment [7], surface modifications [11,12], sensing application [13,14], nanomaterials synthesis [15], CO 2 reduction [9,16], etc, because of the reduced dimensions, the absence of heat damage, a highly reactive environment and an implementable large-area discharges.…”