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Plasma–liquid reactions represent an emerging green chemical process for nitrogen fixation; however, these processes generally exhibit low selectivity for ammonium (NH4+). This limitation highlights the need to explore simple methods to increase NH4+; selectivity. In this study, a catalyst-free falling film dielectric barrier discharge plasma system was employed for the selective synthesis of NH4+. By manipulating the flow state of the discharge gas, NH4+ selectivity was found to increase by 138.4% in the sealed gas flow state compared to the flowing gas state. Furthermore, an increase in the discharge voltage positively influenced the NH4+ selectivity. This phenomenon can be attributed to higher energy input and longer reaction times, which facilitate the formation of nitrogen molecular ions, a critical intermediate in ammonia synthesis. The reaction products were analyzed by UV spectrophotometry and emission spectroscopy to investigate the underlying mechanisms of ammonia synthesis. This study reveals the highest reaction rate reported to date for ammonia synthesis via single-system plasma gas–liquid reactions and offers a novel way to improve both the yield and selectivity of ammonium synthesis via non-thermal plasma gas–liquid interactions. [ABSTRACT FROM AUTHOR]

Heteroatom doping has become an important method to enhance the performance of traditional carbon dots in modern times. Selenium (Se) is a nonmetallic trace element with excellent redox properties and is therefore essential for health. Previous studies have mainly used pure chemicals as selenium sources to prepare selenium‐doped carbon dots (Se‐CDs), but the precursor pure chemicals have the disadvantages of being expensive, difficult to obtain, toxic, and having low fluorescence yields of the synthesised Se‐CDs. Fortunately, our team achieved successful synthesis of selenium carbon dots, exhibiting excellent luminescence and biocompatibility through a one‐step hydrothermal method using selenium‐enriched natural plant Cardamine, as an alternative to selenium chemicals. This approach aims to address the limitations and high costs associated with Se‐CDs precursors. Electron spin resonance spectroscopy (ESR) and cellular antioxidant tests have confirmed the protective ability of Se‐CDs against oxidative damage induced by excessive reactive oxygen species (ROS). A new concept and method for synthesizing selenium carbon dots on the basis of biomass, a rationale for the antioxidant effects on human health, and a wide range of development and application possibilities were offered in this work. [ABSTRACT FROM AUTHOR]

Heteroatom doping has become an important method to enhance the performance of traditional carbon dots in modern times. Selenium (Se) is a nonmetallic trace element with excellent redox properties and is therefore essential for health. Previous studies have mainly used pure chemicals as selenium sources to prepare selenium-doped carbon dots (Se-CDs), but the precursor pure chemicals have the disadvantages of being expensive, difficult to obtain, toxic, and having low fluorescence yields of the synthesised Se-CDs. Fortunately, our team achieved successful synthesis of selenium carbon dots, exhibiting excellent luminescence and biocompatibility through a one-step hydrothermal method using selenium-enriched natural plant Cardamine, as an alternative to selenium chemicals. This approach aims to address the limitations and high costs associated with Se-CDs precursors. Electron spin resonance spectroscopy (ESR) and cellular antioxidant tests have confirmed the protective ability of Se-CDs against oxidative damage induced by excessive reactive oxygen species (ROS). A new concept and method for synthesizing selenium carbon dots on the basis of biomass, a rationale for the antioxidant effects on human health, and a wide range of development and application possibilities were offered in this work., (© 2024 John Wiley & Sons Ltd.)