Recent applications in dielectric barrier discharge and radio frequency plasmas-engineered transition metal electrocatalysts for water splitting

Hydrogen generated by water electrolysis is considered as one of the most promising protocols to partly replace the roles of traditional fossil fuels. However, high-performance electrocatalyst satisfied with the industrial requirement still faces significant challenges. Low-temperature plasma contains numerous high-energy ions, electrons and other reactive species, which can provide a highly reactive environment for tuning the physio-chemical structures of catalysts through plasma milling, etching, doping and/or deposition. It is well-known that high-temperature micro-filaments contained in plasmas can cause some special modifications of the catalyst surface, thus effectively adjusting the physio-chemical structure of latterly engineered compounds. Therefore, low-temperature plasma technologies, especially the dielectric barrier discharge (DBD) and radio frequency (RF) plasmas, can be considered as a green and sustainable strategy for engineering high-performance electrocatalysts for water splitting (hydrogen evolution reaction [HER]; oxygen evolution reaction [OER]). Herein, recent progress of DBD and RF plasmas for fabricating and modifying transition metal-based electrocatalysts (e.g. sulphide, phosphide, selenide, oxide, hydroxide) for hydrogen evolution reaction or OER is comprehensively reviewed, and the role of plasma is also discussed.