Kunfeng Zhao,Hailian Tang,Botao Qiao,Lin Li,Junhu Wang
Au/γ-Fe2O3 and Au/α-Fe2O3 catalysts with identical size of Au nanoparticles, chemical state of Au species, and amount of surface OH– group were prepared. The Au/γ-Fe2O3 catalyst exhibited exceptionally high activity, regardless of the heat treatments. The CO-TPR, sequential pulse reaction, and in situ Raman spectra demonstrate that the much higher activity of Au/γ-Fe2O3 originated from its higher redox property at low temperature. Systematic study shows that this higher-redox-property-based higher activity could be extended to γ-Fe2O3-supported Pt-group metals and to other reactions that follow Mars–Van Krevelen mechanism. This finding may provide a new avenue for catalyst improvement or development by choosing the suitable crystal phase of the oxide support.
In this article, the catalyst Au/γ-Fe2O3@hydroxyapatite (Au/γ-Fe2O3@HAP) consisting of Au nanoparticles supported on the core–shell structure γ-Fe2O3@HAP was prepared through a deposition–precipitation method. The catalyst was characterized by transmission electron microscopy, X-ray powder diffraction, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, N2 adsorption–desorption and atomic absorption spectrometry. The as-prepared Au/γ-Fe2O3@HAP exhibited excellent performance for the reduction of 4-nitrophenolate (4-NP) to 4-aminophenolate (4-AP) in the presence of NaBH4 at room temperature. Thermodynamic and kinetic data on the reduction of 4-NP to 4-AP catalyzed by the as-prepared catalyst were studied. The as-prepared catalyst could be easily separated by a magnet and recycled 6 times with over 92% conversion of 4-NP to 4-AP. In addition, the as-prepared catalyst showed excellent catalytic performance on other nitrophenolates. The TOF value of this work on the reduction of 4-NP to 4-AP was 241.3 h−1. Au/γ-Fe2O3@HAP might have a promising potential application on the production of 4-AP and its derivatives.
危险品化学品经营许可证（带存储）