Energy Intensified Nitrogen Fixation Through Fast Modulated Gas Discharge from Pyramid-shaped Micro-electrode

Plasma-assisted nitrogen fixation has emerged as a promising alternative to conventional nitrogen fixation methods. In this study, we investigate the feasibility of plasma-assisted nitrogen fixation using an AC-driven dielectric barrier discharge generated from the micro-tips of a specially designed fast-modulated pyramid-shaped electrode. The obtained result is compared with the conventional flat electrode. Our results demonstrate that pyramid-shaped micro-tip electrodes can excite more nitrogen molecules than flat electrodes. Thus, pyramid electrodes have 58% more nitrogen oxides yield efficiency at 32% less energy cost. The highest nitrogen fixation is attained at 60% to 70% of oxygen concentration in nitrogen-feeding gas. These findings suggest that discharge through microtip is a promising and viable technology that could play a significant role in reducing the energy cost of the plasma-assisted nitrogen fixation method to meet the growing demand for sustainable nitrogen-based fertilizers.</p

Sustainable Plasma-Catalytic Nitrogen Fixation with Pyramid Shaped μ-Electrode DBD and Titanium Dioxide

This research explores the potential of electric field enforcement in dielectric barrier discharge using specially designed pyramid-shaped μ-electrodes for a plasma-assisted nitrogen fixation process. The obtained results are compared under varying conditions, including the presence and absence of titanium dioxide ((Formula presented.)), different oxygen concentrations in the nitrogen-feeding gas, and residence time. The results demonstrate that the μ-electrodes lead to an enhancement of nitrogen oxidation, which is further intensified by (Formula presented.). The introduction of 60–70 % oxygen with nitrogen achieves the highest level of (Formula presented.) production. The synergistic effect of plasma and the catalytic effect of (Formula presented.) increase the rate of (Formula presented.) production by 20 %, resulting in a 23 % increase in energy yield. The introduction of (Formula presented.) leads to a sharp increase in (Formula presented.) production even at lower oxygen concentrations. The crucial role played by ultraviolet light-induced electron-hole pairs in (Formula presented.) is highlighted to promote nitrogen oxidation. Nevertheless, it is crucial to emphasize that prolonged residence times may cause the photocatalytic effect to generate alternative byproducts rather than (Formula presented.), consequence of excessive oxidation that could prove counterproductive. These findings emphasize the potential of plasma-assisted nitrogen fixation technology in reducing energy costs and meeting the growing demand for sustainable nitrogen-based fertilizers.</p

The effects of pulse shape on the selectivity and production rate in non-oxidative coupling of methane by a micro-DBD reactor

The conversion of methane to ethylene has been investigated in a micro-DBD reactor with electrodes containing charge injector parts and excited with a negatively nano-second pulse voltage superimposed on a positive dc voltage. The effect of changing the characteristics of pulsed voltage such as pulse rise time (5–7 ns), total pulse width (12–14 ns), and pulse fall time (5–7 ns) on generation rate and products selectivity of the methane plasma has been studied. The kinetic model includes twenty species (electron, ions, radicals, and neutrals). The results showed that change in input pulse shape changes the generation rate and selectivity of neutral products. The rate of voltage change during pulse on-time significantly changed the instant C2H4 selectivity. With increasing the pulse rise and fall times the ethylene selectivity decreases, while the hydrogen selectivity increases. Results also showed that the electron reactions are dominant conversion channels during pulse on-time, while they had lower contributions in conversion progress during pulse off-time and the conversion process during this period is mainly governed by the radical reactions

Energy intensified nitrogen fixation through fast modulated gas discharge from pyramid-shaped micro-electrode

Plasma-assisted nitrogen fixation has emerged as a promising alternative to conventional nitrogen fixation methods. In this study, we investigate the feasibility of plasma-assisted nitrogen fixation using an AC-driven dielectric barrier discharge generated from the micro-tips of a specially designed fast-modulated pyramid-shaped electrode. The obtained result is compared with the conventional flat electrode. Our results demonstrate that pyramid-shaped micro-tip electrodes can excite more nitrogen molecules than flat electrodes. Thus, pyramid electrodes have 58% more nitrogen oxides yield efficiency at 32% less energy cost. The highest nitrogen fixation is attained at 60% to 70% of oxygen concentration in nitrogen-feeding gas. These findings suggest that discharge through microtip is a promising and viable technology that could play a significant role in reducing the energy cost of the plasma-assisted nitrogen fixation method to meet the growing demand for sustainable nitrogen-based fertilizers

Development of an Ir/TiO₂ catalytic coating for plasma assisted hydrogenation of CO₂ to CH₄

The hydrogenation of CO2 to methane over a 20 wt% Ir/TiO2 catalytic coating has been investigated in a tubular dielectric barrier discharge (DBD) reactor. The 1.2 µm Ir/TiO2 coating was deposited onto the inner wall of a quartz tube by a combustion-evaporation method from a mixture containing a Ti precursor and a colloidal suspension of Ir nanoparticles (2 nm). The catalyst was characterised by XRD, SEM, TEM/EDS and CO chemisorption. The Ir(0) state in the as-synthesised film was confirmed by XPS. The CH4 conversion increased by 1.5 times, as compared to an empty tube. A maximum CO2 conversion rate of 2.1 μmol s−1 was achieved at a fuel production efficiency of 3.5%. Surface reactions onto the catalyst surface are responsible for enhancement of reaction rate. The results presented in this work open up new possibilities in plasma-catalysis, whereby efficient reactions can be carried out over small volumes of catalyst.</p

Development of an Ir/TiO₂ catalytic coating for plasma assisted hydrogenation of CO₂ to CH₄

The hydrogenation of CO2 to methane over a 20 wt% Ir/TiO2 catalytic coating has been investigated in a tubular dielectric barrier discharge (DBD) reactor. The 1.2 µm Ir/TiO2 coating was deposited onto the inner wall of a quartz tube by a combustion-evaporation method from a mixture containing a Ti precursor and a colloidal suspension of Ir nanoparticles (2 nm). The catalyst was characterised by XRD, SEM, TEM/EDS and CO chemisorption. The Ir(0) state in the as-synthesised film was confirmed by XPS. The CH4 conversion increased by 1.5 times, as compared to an empty tube. A maximum CO2 conversion rate of 2.1 μmol s−1 was achieved at a fuel production efficiency of 3.5%. Surface reactions onto the catalyst surface are responsible for enhancement of reaction rate. The results presented in this work open up new possibilities in plasma-catalysis, whereby efficient reactions can be carried out over small volumes of catalyst.</p

R : Nonoxidative methane coupling in a micro‐DBD with enhanced secondary electron emission

The conversion of methane into transportable and storable materials is crucial in the petrochemical sector. In this study, a specially constructed AC‐driven dielectric barrier discharge (DBD) that has charge injector pyramids on one of the electrodes and runs at ambient temperature and pressure was used to evaluate noncatalytic methane conversion. The obtained result was compared with the traditional flat electrode DBD. It was discovered that the product selectivity in direct nonoxidative methane conversion depended on the discharge conditions. Pyramid electrode plasma sources convert methane up to 50 % $\%$ more than flat electrode plasma due to the appearance of more microdischarges. Pyramid electrode plasma generally has a greater production efficiency than flat electrode plasma, while requiring more operational power. The turnkey solutions offered by the sustainable methane coupling method discussed here may be advantageous for the long‐term small‐scale ethylene exploration scenario

Study of plasma parameters and gas heating in the voltage range of nondischarge to full‐discharge in a methane‐fed dielectric barrier discharge

Experimental data are used in theoretical models to study the effects of input voltage and gas flow rate on plasma and background gas parameters in a voltage range where the transition from nondischarge to full-discharge happens. To this end, a specific methane-fed dielectric barrier discharge is used as a plasma reactor, and electrical modeling, the Boltzmann equation method, and emission spectrum analysis are employed to calculate plasma parameters and gas heating. The output of this study proves that a uniform plasma with a controllable background gas heating is achievable by the adjustment of input parameters such as voltage and gas flow rate in a well-designed dielectric barrier discharge

Development of an Ir/TiO2 catalytic coating for plasma assisted hydrogenation of CO2 to CH4

The hydrogenation of CO2 to methane over a 20 wt% Ir/TiO2 catalytic coating has been investigated in a tubular dielectric barrier discharge (DBD) reactor. The 1.2 µm Ir/TiO2 coating was deposited onto the inner wall of a quartz tube by a combustion-evaporation method from a mixture containing a Ti precursor and a colloidal suspension of Ir nanoparticles (2 nm). The catalyst was characterised by XRD, SEM, TEM/EDS and CO chemisorption. The Ir(0) state in the as-synthesised film was confirmed by XPS. The CH4 conversion increased by 1.5 times, as compared to an empty tube. A maximum CO2 conversion rate of 2.1 μmol s−1 was achieved at a fuel production efficiency of 3.5%. Surface reactions onto the catalyst surface are responsible for enhancement of reaction rate. The results presented in this work open up new possibilities in plasma-catalysis, whereby efficient reactions can be carried out over small volumes of catalyst

Critical review : ‘Green’ ethylene production through emerging technologies, with a focus on plasma catalysis

Over the years, numerous studies have explored the green synthesis of ethylene. Within this context, the focus of this perspective shifts toward plasma technology, which has demonstrated the capability to convert methane into ethylene. Plasma catalysis creates distinctive physical and chemical environments, particularly at normal temperature and pressure, distinguishing it from alternative methods. Nevertheless, the utilization of atmospheric pressure plasma is intricate, posing scientific challenges in the realms of physics and chemistry. In this viewpoint, various key performance aspects are evaluated, encompassing methane conversion efficiency, ethylene selectivity, and specific energy input. These scientific pros and cons are then assessed for their readiness for industrial-scale implementation. Initially, the potential for small-scale ethylene production is examined, leveraging existing robust process technologies to unlock fresh market and supply chain opportunities. Subsequently, the sustainability of plasma technology for green ethylene production is compared to conventional ethylene production and alternative green ethylene production methods, including biomass-based approaches. Contrary to perhaps optimistic expectations, current literature evidence does not uniformly favor the latter, indicating the potential for plasma-based green ethylene processes. Additionally, this paper underscores the importance of considering Environmental, Social, and Governance factors that influence business decisions. Finally, this review underscores plasma technology as a potentially promising approach for green ethylene synthesis from methane, offering unique advantages under normal conditions while simultaneously presenting scientific challenges. It assesses its viability for small-scale production and benchmarks its sustainability against conventional and alternative methods, emphasizing the importance of a sustainable future for the green petrochemical industry