One‐Step Reforming of CO₂ and CH₄ into High‐Value Liquid Chemicals and Fuels at Room Temperature by Plasma‐Driven Catalysis

Abstract

The conversion of CO2 with CH4 into liquid fuels and chemicals in a single‐step catalytic process that bypasses the production of syngas remains a challenge. In this study, liquid fuels and chemicals (e.g., acetic acid, methanol, ethanol, and formaldehyde) were synthesized in a one‐step process from CO2 and CH4 at room temperature (30 °C) and atmospheric pressure for the first time by using a novel plasma reactor with a water electrode. The total selectivity to oxygenates was approximately 50–60 %, with acetic acid being the major component at 40.2 % selectivity, the highest value reported for acetic acid thus far. Interestingly, the direct plasma synthesis of acetic acid from CH4 and CO2 is an ideal reaction with 100 % atom economy, but it is almost impossible by thermal catalysis owing to the significant thermodynamic barrier. The combination of plasma and catalyst in this process shows great potential for manipulating the distribution of liquid chemical products in a given process.

Advances in catalytic conversion of methane and carbon dioxide to highly valuable products

“…This means that the coupling of the plasma with the catalyst did not generate a plasma‐catalytic synergy in NTP process. Nevertheless, Tu and Whitehead observed the plasma‐catalyst synergetic effect on DRM, which is dependent on packing methods . They found that, when the 10 wt% Ni/‐Al 2 O 3 catalyst in flake form calcined at 300°C was partially packed in the plasma, the synergy of plasma‐catalysis was clearly observed, leading to the doubled CH 4 conversion and H 2 yield (17.5%).…”

“…The product distribution in solid catalyst‐plasma system can also be adjusted by introducing third gas (such as O 2 and Ar) into CH 4 /CO 2 . Very recently, Tu and coworkers reported the synthesis of liquid fuels and chemicals from CO 2 and CH 4 at room temperature and atmospheric pressure using a novel DBD plasma reactor with a water electrode . For the DBD plasma process without a catalyst, a total liquid selectivity of 59.1% was achieved with selectivities of 33.7, 11.9, 11.9, and 1.6% for acetic acid, ethanol, methanol, and acetone, respectively (in Figure A).…”

“…Photocatalytic CO 2 reforming of methane over Pt/black TiO 2 catalyst dispersed on the light‐diffuse‐reflection‐surface of a SiO 2 substrate: (A) Photo H 2 , (B) Photo CO , (C) Quantum efficiency vs temperature, and (D) Quantum efficiency vs wavelength. Reprinted with permission from []. Copyright © 2016, American Chemical Society.…”

“…Nevertheless, Tu and Whitehead observed the plasma-catalyst synergetic effect on DRM, which is dependent on packing methods. 279 They found that, when the 10 wt% Ni/-Al 2 O 3 catalyst in flake form calcined at 300°C was partially packed in the plasma, the synergy of plasma-catalysis was clearly observed, leading to the doubled CH 4 conversion and H 2 yield (17.5%). This synergistic effect also contributes to a significant enhancement in the energy efficiency of feed gas conversion.…”

Non‐oxidative methane conversion in diffuse, filamentary, and spark regimes of nanosecond repetitively pulsed discharge with negative polarity

“…In the past few decades, various atmospheric nonthermal plasma (NTP) technologies had been developed for direct methane conversion, including corona discharge, plasma jet, dielectric barrier discharge (DBD), pulsed discharge, spark discharge, gliding arc discharge, radio‐frequency discharge, and microwave discharge . The NTP technologies can generate high reactive species at relatively low temperature in favor of reducing the manufactory requirements and possibly enhancing the catalysis performance .…”