Plasma–Liquid Interactions in the Synthesis of Gold Nanomaterials: Current Advances and Future Perspectives

Plasma–liquid interactions (PLIs) have emerged as a rapid and reagent-minimized platform for the synthesis of gold nanomaterials (GNMs) with tunable size, morphology, crystallinity, and surface chemistry. In contrast to conventional wet-chemical routes, non-thermal atmospheric-pressure plasmas reduce HAuCl4 through highly reactive species generated at the gas–liquid interface. This review consolidates the field by classifying PLIs systems into four categories based on the discharge configuration, including plasma electrochemistry, plasma jet, solution plasma, and plasma aerosol, and critically compares their mechanisms and operational parameters. We show that the relative weighting of key process variables is strongly configuration-specific, with short-lived species initiating burst nucleation and long-lived neutrals sustaining autocatalytic growth. Furthermore, the review highlights how the distinct characteristics of each PLI configuration affect nanoparticle formation, morphology evolution, and physicochemical properties, providing practical guidance for selecting appropriate plasma systems for the controlled synthesis of gold nanomaterials.