The aim of this work consists of the evaluation of atmospheric pressure dielectric barrier discharges for the conversion of greenhouse gases into useful compounds. Therefore, pure CO 2 feed flows are administered to the discharge zone at varying discharge frequency, power input, gas temperature and feed flow rates, aiming at the formation of CO and O 2 . The discharge obtained in CO 2 is characterized as a filamentary mode with a microdischarge zone in each half cycle of the applied voltage. It is shown that the most important parameter affecting the CO 2 -conversion levels is the gas flow rate. At low flow rates, both the conversion and the CO-yield are significantly higher. In addition, also an increase in the gas temperature and the power input give rise to higher conversion levels, although the effect on the CO-yield is limited. The optimum discharge frequency depends on the power input level and it cannot be unambiguously stated that higher frequencies give rise to increased conversion levels. A maximum CO 2 conversion of 30% is achieved at a flow rate of 0.05 L min −1 , a power density of 14.75 W cm −3 and a frequency of 60 kHz. The most energy efficient conversions are achieved at a flow rate of 0.2 L min −1 , a power density of 11 W cm −3 and a discharge frequency of 30 kHz.

A one‐dimensional fluid model for a dielectric barrier discharge in methane, used as a chemical reactor for gas conversion, is developed. The model describes the gas phase chemistry governing the conversion process of methane to higher hydrocarbons. The spatially averaged densities of the various plasma species as a function of time are discussed. Besides, the conversion of methane and the yields of the reaction products as a function of the residence time in the reactor are shown and compared with experimental data. Higher hydrocarbons (C2Hy and C3Hy) and hydrogen gas are typically found to be important reaction products. Furthermore, the main underlying reaction pathways are determined.

While protein or enzyme immobilization methodologies are readily applicable in a majority of industrial processes, some lacunas still remain. For example, the multi-step, wet-chemical nature of current immobilization reactions limits straightforward bio-film fabrication in continuous production units. As such, a fast and preferably single step immobilization technique, minimizing solvent use and decoupling deposition substrate from used method is awaited. In this research, an atmospheric pressure plasma reaction environment is chosen for its flexibility in terms of reactivity and the ease of coating depositions on a wide variety of substrates. Organic coating precursors such as acetylene or pyrrole are injected simultaneously with an atomized enzyme solution directly in the discharge. By atomizing the enzyme solution, the enzyme molecules are surrounded by a watery shell. It is envisioned that such droplet act as ''shuttles'', delivering the enzymes to the discharge while protecting them from the harsh plasma conditions. In the discharge, polymerization of the added organic coating precursor takes place and consequently, the enzyme molecules become trapped in the growing polymer network. In addition, atomization of the protein solution favors the spatial distribution of the proteins in the coating. Several enzymes are evaluated and enhanced temperature and solvent stability is observed. Moreover, single molecule fluorescence, enzyme activity and bio-recognition experiments demonstrate protein integrity after plasma assisted immobilization.

Plasma coating technologies have been demonstrated as being promising for the fabrication of bioactive and biocompatible materials, among others. Reported efforts are exclusively focused on the two‐step approaches, in which the bioactive component is first immobilized on a substrate, followed by a (vacuum) plasma polymerization treatment or vice versa. However, we believe that upon minimizing the plasma energy, numerous bioactive substances such as enzymes and nucleic acids can be immobilized directly in plasmas via copolymerization with organic precursors, or by direct entrapment in the organic polymer. Therefore, a dielectric barrier discharge was employed at atmospheric pressure and ambient temperature to deposit organic coatings with reasonable growth rates at power input and frequency values as low as possible. Two promising precursors, acetylene and pyrrole, were selected out of 22 organic monomers for full physicochemical characterization. While the acetylene polymer film shows resemblance with its vacuum plasma analogue, polypyrrole coatings produced in vacuum and atmospheric plasmas differ significantly.