Non-equilibrium atmospheric pressure plasmas interacting with liquids offer a unique source of highly reactive chemistry beneficial for many applications in biology, medicine and advanced materials manufacturing. Plasma-liquid interactions can involve synthesis of nanoparticles (NPs) and inactivation of pathogens. While the underlying mechanisms of these processes are poorly understood, the application potential is enormous.  

The presentation will highlight some examples of reaction pathways responsible for the synthesis of AgNPs at the plasma-liquid interface. This will include a detailed analysis of the reduction mechanism of Ag⁺, the initial step for the formation of NPs in solution, through various mechanisms proposed in literature including solvated electrons, UV photons and hydrogen atoms.

Plasmas are typically oxidizing and not reducing environments as they produce an abundant source of reactive oxygen species (ROS). We will present the possibility of using these ROS for the functionalization of NPs and in particular the generation of luminescent and hydrophobic water-soluble silicon quantum dots. In addition, we will discuss the importance of these ROS in the inactivation of pathogens in solutions. We will conclude with an overview of the challenges and opportunities ahead.