Ultrathin Nitrogen-Enriched Carbon Cover-Enhanced Stability and Wettability of Au Nanocrystals on Core-Shell Fe3O4@N-Carbon Particles for Heterogeneous Catalysis

We report a core-shell Fe3O4@nitrogen-doped carbon@Au@nitrogen-doped carbon (Fe3O4@N-Carbon@Au@N-Carbon) nanocatalyst based on a combined strategy, layer-by-layer deposition of aminophenol-formaldehyde (APF) resin and subsequent pyrolysis. Isolated Au nanocrystals were sandwiched between ultrathin nitrogen-enriched carbon cover and core-shell Fe3O4@N-Carbon. Transmission electron microscopy, X-ray diffractor, X-ray photoelectron spectroscopy, and other analysis methods were used to characterize the catalyst. Ultrathin nitrogen-enriched carbon cover could stabilize Au nanocrystals, enhance their wettability with liquid polar organic substrates, and offer a relatively short transfer route of substrates towards active Au sites during catalytic transformations. For the reduction of 4-nitrophenol, 2-nitrophenol, 4-nitroaniline and 2-nitroaniline, the catalyst exhibits corresponding high turnover frequency of 378, 522, 834 and 846 h(-1), respectively. The catalyst also shows high stability over 20 cycles almost without obvious structural damage and activity loss for reduction of 4-nitrophenol.