**1. Introduction**

Many fields offer solutions for CO2 utilization. Among them are thermochemical processes, electrolysis [1] and plasma catalysis; the latter has the smallest technology readiness level (TRL) but also offers a large potential for future improvements [2–4]. Attention is focused mostly on four types of plasma reactors: dielectric barrier discharges (DBDs) [5], gliding arc (GA) [6,7], atmospheric pressure glow discharges (APGD) [8,9] and microwave (MW) plasmas [10,11]. Increasing their energy efficiency and conversion at ambient pressure is the main point of concern. We recently presented reactors using a direct current APGD, which delivered promising results [12]. To further improve the previous design, it was scaled and now uses a laminar gas flow instead of a turbulent one. To be used industrially, a plasma reactor should operate at ambient pressure. However, this makes it hard to maintain a stable discharge. Two major difficulties are the negative differential resistance [13] and glow-to-arc transition [14]. A discharge thus tends to form a narrow, low-resistance arc that can damage the plasma source and is not useful in catalysis. To suppress these effects, current control strategies or vortex gas flow [14] are often used in recent studies to disperse the plasma [8]. The reactor setup presented here uses a magnetic field instead to force the plasma into a large disc-like volume. This approach is viable for various discharge forms, such as gliding arc plasma reactors [15,16]. A laminar gas flow can be then used to introduce energy into the working gas as homogeneously as possible. This communication aims to give an update on the ongoing design process for an improved plasma reactor for the CO2 splitting reaction.

**Citation:** Renninger, S.; Rößner, P.; Stein, J.; Lambarth, M.; Birke, K.P. Towards High Efficiency CO2 Utilization by Glow Discharge Plasma. *Processes* **2021**, *9*, 2063. https://doi.org/10.3390/pr9112063

Academic Editors: Alon Kuperman and Alessandro Lampasi

Received: 11 October 2021 Accepted: 15 November 2021 Published: 18 November 2021

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