Polyacrylamide Gel Scaffold Immobilized with Silver Nanoparticles as SERS Substrates and Catalysts for H2 Generation via Methanolysis of NaBH4

Abstract

This report discloses the preparation of a series of polyacrylamide materials with unique surface morphology. Polyacrylamide with N,N′-methylenebisacrylamide cross-linking provides reactive sites for the reduction of silver nitrate. The reaction refurbishes the relatively smooth polymer surface to clusters of submicron cubes impregnated with silver nanoparticles (AgNPs) and residual Ag(+1) ions. Subsequent treatment with NaBH4 grows additional silver structures from the AgNPs seeded in the polymer to give an overall morphology reminiscent of the famous great barrier reefs, the namesake of this material─the Great Barrier Gel (GBG). The GBG surface features a high content of active silver nanostructures. The use of GBG as a substrate for surface-enhanced Raman scattering (SERS) and a film catalyst for the methanolysis of NaBH4 demonstrates its versatility. The SERS sensitivity of this material is 10–10 M, or better, as assessed using 4-aminophenyl disulfide. It catalyzes the production of H2 by the methanolysis of NaBH4 without significant loss of activity in an exhaustion test. These methods create an enlarged surface area on the shape-adapting polymer material, chemically and productively, while generating a least amount of chemical waste.