Plasma‐Electrified Synthesis of Atom‐Efficient Electrocatalysts for Sustainable Water Catalysis and Beyond

Abstract The downsizing of metal structures to the nano and atomic level, thereby creating nanoparticle catalysts (NPCs), sub‐nanometer cluster catalysts (SNCCs), or single‐atom catalysts (SACs), has gained significant interest. In particular, synthesizing these types of catalysts using low‐temperature plasma‐electrified methods is an emerging field which is highly applicable to electrochemical water splitting for the sustainable production of green hydrogen. Surface modification via plasma treatment provides a route for nanoparticle immobilization or single‐atom trapping which ensures high atom utilization during electrolysis reactions. Plasma can also be used to create NPCs, SNCCs, and SACs from various precursors as well as modify their surface properties once formed which impacts significantly on the oxygen evolution reaction (OER) and hydrogen evolution reaction (HER). Therefore, in this review we emphasize the role that low‐temperature plasma‐electrified synthetic strategies play in electrocatalyst development for water splitting reactions and explore the crucial relationship between the electronic and coordination environment of atom‐efficient catalysts (AECs) and their resulting catalytic activity. We also discuss methods to characterize these types of catalysts and the possibility of scaling up this technology which will be required for commercial applications.