Microwave-Enabled Size Control of Iron Oxide Nanoparticles\non Reduced Graphene Oxide

Abstract

Nanoparticle-functionalized\n2D material networks are promising\nfor a wide range of applications, but in situ formation of nanoparticles\nis commonly challenged by rapid growth. Here, we demonstrate controlled\nsynthesis of small and dispersed iron oxide nanoparticles on reduced\ngraphene oxide (rGO) networks through rapid localized heating with\nmicrowaves with low-cost iron nitrate as the precursor. The strong\ncoupling of the microwave radiation with the rGO network rapidly heats\nthe network locally to decompose the iron nitrate and generate iron\noxide nanoparticles, while cessation of microwaves leads to rapid\ncooling to minimize crystal growth. Small changes in the microwave\nreaction time (<1 min) led to very large changes in the iron oxide\nmorphology. The solid-state microwave syntheses produced narrower\nnanoparticle size distribution than conventional heating. These results\nillustrate the potential of solid-state microwave syntheses to control\nthe nanoparticle size on 2D materials through rapid localized heating\nunder the microwave process conditions, which should be extendable\nto a variety of transition metal oxide–rGO systems.