Ultrathin Graphene-Like Carbon-Coated Iron Oxide Nanocrystals for Applications in Corrosive Environments

Here we report a solution-phase strategy for depositing ultrathin graphene-like carbon onto iron oxide nanocrystals (NCs) for corrosion resistance in magnetic and electrocatalytic applications. Thermal decomposition of iron carboxylates is a well-known method for generating uniform, size-tunable iron oxide NCs. When this reaction is completed at elevated temperatures and for longer times, the nanomaterials become unreactive to further growth and the magnetic nanomaterial survives treatment with concentrated nitric acid. X-ray photoelectron and Raman spectroscopies reveal that these materials contain graphene-like carbon. Metal carboxylates can decompose and yield carbon monoxide (CO), which we detect via gas chromatography-mass spectrometry. We speculate that when this CO is generated near a growing iron oxide surface, it disproportionates to yield carbon dioxide and carbon. Our approach is notable given that a low-temperature, solution-phase route for forming carbon materials such as graphene from the bottom up has remained elusive.