Galvanic exchange on reduced graphene oxide. Designing a multifunctional two-dimensional catalyst assembly

The two-dimensional network of reduced graphene oxide (RGO) is decorated with silver and gold nanoparticles. The silver nanoparticles deposited on RGO by photocatalytic reduction are subjected to galvanic exchange with Au3+ ions to transform them into gold nanoparticles. This compositional change on the RGO surface demonstrates RGO's versatile ability to anchor a wide array of nanoparticles and facilitate chemical transformations. Coupled with RGO's unique ability to capture and transport electrons, galvanic exchange is used to contrive a two-dimensional nanocatalyst mat. Raman studies show that metal nanoparticles anchored on reduced graphene oxide facilitate enhancement of Raman bands. Using methyl viologen as a probe we elucidate the photocatalytic activity of the semiconductor–RGO–metal nanoassembly and highlight the mediation of RGO in charge transfer processes.