Iron catalysis has attracted a wealth of interdependent research for its abundance,low price,and nontoxicity.Herein,a convenient and stable iron oxide(Fe2O3)‐based catalyst,in which active Fe2O3nanoparticles(NPs)were embedded into carbon films,was prepared via the pyrolysis of iron‐polyaniline complexes on carbon particles.The obtained catalyst shows a large surface area,uniform pore channel distribution,with the Fe2O3NPs homogeneously dispersed across the hybrid material.Scanning electron microscopy,Raman spectroscopy and X‐ray diffraction analyses of the catalyst prepared at900°C(Fe2O3@G‐C‐900)and an acid‐pretreated commercial activated carbon confirmed that additional carbon materials formed on the pristine carbon particles.Observation of high‐resolution transmission electron microscopy images also revealed that the Fe2O3NPs in the hybrid were encapsulated by a thin carbon film.The Fe2O3@G‐C‐900composite was highly active and stable for the direct selective hydrogenation of nitroarenes to anilines under mild conditions,where previously noble metals were required.The synthetic strategy and the structure of the iron oxide‐based composite may lead to the advancement of cost‐effective and sustainable industrial processes.
Selective oxidation of glycerol is a hot topic.Increased biodiesel production has led to glycerol oxidation over Au- and Pt-based catalysts being widely studied.However,Pt catalysts suffer from deactivation because of weak metal-support interactions.In this study,multi-walled carbon nanotube（MWCNTs）-pillared nitrogen-doped graphene（NG） was prepared by direct pyrolysis of melamine on MWCNTs,and the synthesized NG-MWCNT composite was used as the support for Pt.Characterization results showed that the surface area（173 m^2/g） and pore volume of the NG-MWCNT composite were greater than those of bare MWCNTs and the separated melamine pyrolysis product（CH_x）.Pt（1.4±0.4 nm） dispersion on the NG-MWCNTs was favorable and the Pt/NG-MWCNT catalyst was highly active and selective in the oxidation of glycerol to glyceric acid（GLYA） in base-free aqueous solution.For example,the conversion of glycerol reached 64.4% with a GLYA selectivity of 81.0%,whereas the conversions of glycerol over Pt/MWCNTs and Pt/CN_x were 29.0% and 31.6%,respectively.The unique catalytic activity of the Pt/NG-MWCNTs is attributed to well-dispersed Pt clusters on the NG-MWCNTs and the electron-donating effect of the nitrogen dopant in the NG-MWCNTs.
A series of Pd catalysts were prepared on different supports（Fe2O3,SiO2,ZnO,MgO,Al2O3,carbon,and Amberlyst-45） and used in the selective hydrogenation of phenol to cyclohexanone in water.The Amberlyst-45 supported Pd catalyst（Pd/A-45） was highly active and selective under mild conditions（40-100 ℃,0.2-1 MPa）,giving a selectivity of cyclohexanone higher than 89%even at complete conversion of phenol.Experiments with different Pd loadings（or different particle sizes） confirmed that the formation of cyclohexanone was a structure sensitive reaction,and Pd particles of12-14 nm on Amberlyst-45 gave better selectivity and stability.
