Redox-Active Au Nanoparticles Self-Assembled at Liquid-Liquid Interface via C-Au Functionalization for Dye Degradation Electrocatalysis

This work presents the synthesis of poly(vinylpyrrolidone)-stabilized gold nanoparticles (Au NPs) and their subsequent functionalization with molecules bearing terminal alkynes. The ligand exchange occurs at the liquid-liquid interface (LLI), resulting in the formation of Au NPs stabilized through the covalent C-Au functionalization. Simultaneously, structured composite films are formed, driven by the self-assembly of the Au NPs supported by the polymer. A comparative analysis involving three distinct alkyne-terminated derivatives reveals that film formation is favored when the ligand includes an aromatic unit such as in a ferrocenyl-stilbene derivative. The LLI films can be easily transferred to solid a support for their characterization. Additionally, it is demonstrated that these films serve as a potential electrocatalytic platform. As a proof of concept, we demonstrate that the electrochemically active ferrocene-based Au NPs films can efficiently remove methylene blue via an electro-Fenton-like reaction, surpassing the efficiency of the non-redox phenylacetylene Au NP films.