Non-thermal plasma manufacturing and functionalization: a review on nano-sized catalytic materials synthesis and support structure control

The role of catalysts becomes important to achieve the increase in efficiency and environmental problems, which are the key challenges of energy conversion technology and chemical industry in the 21st century. However, conventional catalyst manufacturing methods had difficulty in causing the aggregation of metal particles or selectively synthesizing the desired structure due to the limitation of thermodynamic equilibrium. Non-thermal plasma (NTP) is an ionized gas in which ions, electrons, radicals, photons, and excited neutral species coexist under much lower or even ambient temperatures. This paper covers the principle of various types of NTP such as dielectric barrier discharge (DBD), liquid plasma, Gas-Liquid Interfacial plasma (GLIP) as well as their corresponding electron-driven nucleation and crystal growth mechanisms. Specifically, NTP applications on the synthesis of catalytic materials from nano-sized to single-atom catalysts and high value-added high-entropy alloys (HEA), as well as the functionalization of supporting materials with controlling oxygen vacancies, heteroatom doping and the exfoliation of 2D materials are mentioned. In conclusion, NTP is capable of applying plasma-induced reactions beyond the conventional thermodynamic limits and is an essential tool for realizing carbon neutrality and developing next-generation high performance catalysts.