Plasma catalysis for nitrogen fixation reactions

The preferences for localized chemicals production and changing scenarios of renewable electricity cost gives a renewed boost to plasma-assisted valuable chemicals production. Especially, plasma-assisted nitrogen fixation for fertilizer production has the potential to largely change the energy structure in bulk chemicals production. Nitrogen is the most fundamental element for sustaining life on earth and responsible for production of a wide range of synthetic products. The chemical nitrogen fixation process, i.e. the Haber–Bosch ammonia production process, is one of the most important chemical processes, which supports ∼40% of the global population by producing more than 130 million tons of ammonia per year and requires ∼1–2% of the world’s total energy consumption. Thermal plasma nitric oxide synthesis was already commercialized in 1903, however it had lower energy efficiency. It is theoretically possible to fix nitrogen with lower energy input by non-thermal plasmas. Therefore, much effort has been expended to develop and improve plasma NO, NH3 and HCN syntheses—this includes investigation of the different types of plasma reactors, the synergy between plasma and catalysts as well as improvement of the heat exchange. All these reported literature efforts have been summarized and critically analyzed in this book chapter. An outlook on further possible developments in plasma-assisted chemical synthesis processes is also given.