作者： George K. Larsen^†, Will Farr^†, and Simona E. Hunyadi Murph^†‡

^† National Security Directorate, Savannah River National Laboratory, Aiken, South Carolina 29808, United States

^‡ Department of Physics and Astronomy, University of Georgia, Athens, Georgia 30602, United States

 

摘要：We investigate Au-decorated Fe2O3 nanoparticle catalysts, Fe2O3–Au, where the supporting Fe2O3 nanoparticles are of different shapes: spheres, rings, and tubes. The decoration procedure for the Fe2O3–Au nanoparticles is identical for each shape, and is analogous to the synthesis of pure Au nanoparticles (AuNPs). These similarities allows for direct comparison between the different shapes and the pure AuNPs. The morphological, optical, and magnetic characterizations reveal that the Fe2O3–Au nanoparticles are hybrid structures exhibiting both plasmonic and magnetic properties. The different shape Fe2O3–Au nanoparticles and the AuNPs are evaluated for their ability to catalytically reduce 4-nitrophenol. Remarkably, it is found that Fe2O3–Au nanoparticles are more efficient catalysts than AuNPs because they can achieve the same, or better, catalytic reaction rates using significantly smaller quantities of Au, which is the catalytically active material. Taking into account the Au-loadings, the Fe2O3 rings and tubes are superior to the Fe2O3 spheres as catalytic supports due to their γ-Fe2O3 crystal phase. It is also shown that the Fe2O3–Au nanoparticles have the additional benefit for catalysis in that they can be recovered and reused via magnetic collection. Furthermore, the Fe2O3–Au nanoparticles and AuNPs are found to efficiently transduce heat from light through plasmonic absorbance, and this phenomenon is exploited to demonstrate the photothermal catalytic reduction of 4-nitrophenol.