Fourier‐transform infrared spectroscopy and proton‐transfer‐reaction–mass spectrometry are used in a complementary way to study gas‐phase processes during decomposition of ethanol in a microwave plasma torch. Decomposition products (C, C2 and simple hydrocarbons) reassemble into higher hydrocarbons and graphene nuclei and further grow into graphene nanosheets (GNS). Depending on microwave power, ethanol flow rate and molecular gas admixture, the material structure changes from amorphous to crystalline. The presence of C2n + 1H y species was found to be responsible for the formation of defects in the GNS structure. O2 and H2 admixtures change the gas temperature axial profile and consequently modify reaction pathways influencing growth and production rate of GNS. Determination of reaction pathway selectivity enables us to predict whether high‐quality or defective GNS are produced.

The chemical processes initiated by electrical discharges in prebiotic atmospheres became a hot topic during the past decade due to the recent extensive discovery of exoplanets. The biggest atmospheric data collection is currently available about the atmosphere of the Saturn's moon Titan that is composed mainly of nitrogen and methane at low surface temperature of about 95 K and pressure of about 1.5 atm. The present work deals with the laboratory simulation of the chemical processes initiated by the electrical discharge in the gaseous mixture related to the Titan atmosphere under laboratory conditions. The ongoing chemical processes, the resulting stable products, and their transformation into more complex substances were studied by the in situ mass spectrometry with proton ionization (PTR-MS) of the exhausting gas. The presence of many aliphatic and some aromatic hydrocarbons was confirmed as well as many amino and cyano compounds. The increasing concentration of methane has produced more substances with higher molecular weight and less simple substances that were consumed in the formation of more complex substances.

The pinhole discharge using a novel electrode configuration was generated in various water–ethanol mixtures. Proton transfer reaction time-of-flight mass spectrometry was used for the diagnostics of stable discharge products. The sampling was realized by nitrogen constant flow over the liquid surface. Mostly, aliphatic hydrocarbons were detected. The number of products and their concentrations was observed in the dependence on the changing experimental conditions: alcohol concentration in the solution, the electrodes polarity, and the discharge duration. More compounds were detected with the increasing alcohol concentration and in the case of the positive polarity of the pinhole electrode.