Plasma catalysis is gaining increasing interest for various gas conversion applications, such as CO₂ conversion into value-added chemicals and fuels, CH₄ activation into hydrogen, higher hydrocarbons or oxygenates, and NH₃ synthesis. Other applications are already more established, such as for air pollution control, e.g. volatile organic compound remediation, particulate matter and NO_x removal. In addition, plasma is also very promising for catalyst synthesis and treatment. Plasma catalysis clearly has benefits over ‘conventional’ catalysis, as outlined in the Introduction. However, a better insight into the underlying physical and chemical processes is crucial. This can be obtained by experiments applying diagnostics, studying both the chemical processes at the catalyst surface and the physicochemical mechanisms of plasma-catalyst interactions, as well as by computer modeling. The key challenge is to design cost-effective, highly active and stable catalysts tailored to the plasma environment. Therefore, insight from thermal catalysis as well as electro- and photocatalysis is crucial. All these aspects are covered in this Roadmap paper, written by specialists in their field, presenting the state-of-the-art, the current and future challenges, as well as the advances in science and technology needed to meet these challenges.

NO removal is studied in N2/NO and in N2/NO/C2H4 mixtures through time-resolved laser-induced fluorescence in the afterglow of a pulsed homogeneous discharge. NO density measurements are compared with predictions of a 0D model on a large range of parameter values, such as the specific deposited energy and the ethene initial concentration. It is shown that dissociation of NO through collision with the N2(a′1Σu−) state play the main part in the NO removal kinetic. Moreover, quenching of N2(a′1 Σu−) by C2H4 leads to a drastic decrease of the NO removal efficiency when ethene is added to N2/NO. The determined rate coefficient value for the quenching mechanism is (4±2)×10−10 cm3 s−1.