Phenolic driven decoration of silica with Ag nanoparticles: Towards sustainable water remediation

The development of effective systems for the removal of toxic compounds from wastewater is an important goal in the production of materials for environmental applications. In this work we report a sustainable approach for the design and development of silver-decorated hybrid silica nanoparticles for the adsorption and catalytic degradation of toxic dyes. Different bio-available and inexpensive phenolic precursors were selected to chelate and reduce silver ions, and the final nanoparticles architecture was modified by exploring two different synthesis strategies. In the first route, silica nanoparticles were formed in a solution containing both phenolic and metallic components, whereas, in the second route, silver ions were added in an environment where hybrid nanoparticles have already been formed. It was shown that the appropriate choice of both phenolic component and the synthetic route can strongly influence the catalytic activity towards dye degradation. Indeed, the proposed systems show almost complete degradation and reduction of Methylene Blue and 4-Nitrophenol, depending on the exposure and stability of the silver metal active sites.