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Open position: Bachelor thesis
Plasma-Driven Catalytic Oxidation of n-Butane: over MnO₂, CaO, and Composite Catalysts in Microarray Reactors
The combination of dielectric barrier discharge (DBD) plasma and catalysts offers a promising avenue for hydrocarbon conversion, particularly for n-butane oxidation. Plasma generates highly reactive species, such as radicals and ions, that can activate reaction pathways unavailable under conventional catalytic conditions. Understanding how plasma modifies catalyst surfaces and how catalysts influence plasma reactivity is critical for optimizing these systems. MnO₂, known for its redox properties, and CaO, valued for its basicity, provide an ideal platform for exploring these synergistic effects.
This project focuses on the plasma-assisted oxidation of n-butane over catalysts, utilizing a microarray DBD reactor. Reaction products will be analyzed in detail using FTIR spectroscopy to determine conversion rates and product distributions. This approach enables a detailed examination of the plasma-catalyst synergy and its impact on n-butane oxidation. By varying plasma parameters and catalyst compositions, the study aims to uncover how plasma modifies catalytic behavior and how catalysts, in turn, influence plasma chemistry. In addition, the study will also measure the voltage, current, and charge during discharge to quantitatively characterize plasma parameters.
MnO₂ acts as an oxidation-reduction catalyst in the reaction, which can promote the C-H bond cleavage of n-butane by providing active oxygen species (such as surface oxygen or oxygen vacancies), thereby enhancing the reaction activity. CaO, with its strong alkalinity, can effectively adsorb and activate hydrocarbon molecules, reduce reaction energy barriers, and further optimize product distribution. The electrical parameters can directly reflect the intensity and characteristics of plasma discharge, closely related to the active species generated by plasma, and are the basis for understanding the interaction between plasma and catalysts. FTIR spectroscopy can quantitatively detect gas-phase reaction products and deeply study the synergistic effect of plasma catalysts and their influence on the n-butane oxidation reaction pathway.
Contact person:
Yue Cheng (NB 5/172),
Judith Golda (NB 5/127),
Prerequisites:
Previous knowledge of plasma physics is desirable, but not required
When?: By arrangement
Laboratory tour: NB 5/172
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Open position: Bachelor thesis
Determination of the conversion of CO₂ in a microplasma array using emission spectroscopy
The microplasma array is based on a dielectric barrier discharge (DBD) and is to be used to convert environmentally harmful gases such as volatile organic compounds (VOCs) or CO₂. The aim is to make the conversion of substances as energy-efficient as possible by integrating catalysts into the discharge in future. However, precise knowledge of the converted densities is essential for successful integration. In particular, the conversion of CO₂ to CO and O plays a central role, as it forms the basis for quantifying the converted quantities. Measuring these densities is often a challenge. Although methods such as TALIF (laser method) or FTIR spectroscopy (IR absorption spectroscopy) are possible, they can only be used to a limited extent in plasma operation.
A promising alternative to measuring the CO and O densities in the discharge is the use of actinometry. This spectroscopic method makes it possible to analyze the emission of the plasma directly by observing the emissions of the species of interest and an actinometer gas with a known density. While the measurement of the emission spectrum is relatively easy to perform, the evaluation and determination of the densities is a much greater challenge, since, among other things, more precise knowledge of the electron energy distribution function (EEDF) is required.
The project is part of project area A6 in SFB 1316, which deals with the investigation of interactions between DBDs and catalysts.
Contact:
Henrik van Impel (NB 5/171),
Judith Golda (NB 5/127),
Prerequisites:
Previous knowledge of plasma physics is desirable but not required.
When?: by arrangement
Laboratory tour: NB 5/173
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Open position: Bachelor thesis
Characterization of the hydrogen peroxide production of an atmospheric pressure plasma jet operated with ns pulses
The transport of reactive species from an atmospheric pressure plasma jet (APPJ) into liquids offers various applications, such as the plasma-assisted biocatalysis. Previous work has demonstrated that APPJs operated in noble gases with RF excitation can be used effectively for plasma-assisted biocatalysis. However, the use of noble gases is not economical or sustainable for large-scale applications, so alternative operating gases such as nitrogen or air are attractive. In addition to RF excitation, the capillary plasma jet used can also be operated with higher voltage pulses in the ns range, so that operation in nitrogen or air is possible.
In this bachelor thesis, the hydrogen peroxide production of the Capillary Plasma Jet operated with ns pulses is to be investigated, as hydrogen peroxide is the required species in biocatalysis. This is initially carried out in helium in order to ensure a direct comparison with RF operation. Subsequently, the operating gas can be changed to nitrogen or air and the hydrogen peroxide production can be characterized in this mode. In order to be able to apply the investigations to biocatalysis, the hydrogen peroxide concentration in plasma-treated liquids is measured using spectrophotometry and UV absorption.
Contact:
Steffen Schüttler (NB 5/66),
Judith Golda (NB 5/127),
Prerequisites:
Previous knowledge of plasma physics is desirable, but not required
When?: by arrangement
Lab tour: NB 5/28
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Public Relations
Doors open with the mouse
On 3th October, the Faculty of Physics at the Ruhr University Bochum invited children to the Mouse Day. After the physics show, the children experimented in numerous workshops and explored the world of physics. In the plasma workshop, participants learned about plasmas and their important applications, such as coating surfaces. They were able to ignite plasmas, experiment and coat samples using the sputter coater.
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Conference
Two PhD Students at Hakone conference
Soad Mohsenimehr and Henrik van Impel (A6) gave presentations on their latest research at the 18th Hakone Conference, which took place in Padua, Italy, from September 1st to 6th, 2024. The event featured numerous insightful presentations dealing with low-temperature plasmas at atmospheric pressure and their applications in plasma chemical processes. One of the highlights of the conference was the active participation of students: 22 of the 56 presentations were given by PhD students, which created a very appealing environment for young researchers. In particular, dielectric barrier discharges were discussed in terms of their efficiency when used with catalysts and the basic physical dynamics of the discharges. Other topics included plasma applications in agriculture and food processing as well as the interaction between plasma and liquid. In addition to the scientific findings, the conference provided an excellent platform for PhD students to network with international participants from 24 countries, promoting collaboration between disciplines.
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Workshop
Japanese-German Workshop on Low-Temperature Plasma Application
A workshop with guests from Japanese universities/ research institutions and members of the chair of Experimental Physics V was held on 25th and 26th of July. Initiated by Prof. Aramaki from Nihon University, the workshop brought together long time collegues who stayed as collaborators at EP V during the last 20 years. All of them conduct research in the field of low temperature plasmas. This covers a broad range from the application for agriculture or semiconductor fabrication as well as developing new kinds of diagnostics like vortex laser spectroscopy. With these topics a perfect overlap with the research of the CRC is given so that the workshop consists not only of one day of presentations but also one day of laboratory visits allowing for the guests to get an overview of the current local plasma research.
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Conference
Five Posters at ESCAMPIG
This year's ESCAMPIG conference took place in Brno, Czech Republic. Three members of Experimental Physics II and one member of AEPT from Bochum took part and contributed to the conference with five posters. In addition to the interesting plenary lectures by well-known personalities such as Peter Bruggeman (USA), Luís L. Alves (Portugal), Kinga Kutasi (Hungary) and Holger Kersten (Germany), there was a variety of around 160 other posters on both modelling and experimental topics. In addition to the professional exchange, the conference offered excellent evening events, such as the welcome party with a dance class and Czech specialities or the conference dinner with live music and a cosy atmosphere. We had many interesting discussions at the conference and met new and old acquaintances, which is why we came away from the conference with very positive experiences overall.
