Palladium nanoparticles supported on core-shell and yolk-shell Fe3O4@nitrogen doped carbon cubes as a highly efficient, magnetically separable catalyst for the reduction of nitroarenes and the oxidation of alcohols

The preparation of palladium nanoparticles (Pd NPs) supported on Fe3O4@nitrogen doped carbon (N-C) core-shell (C-S) and yolk-shell (Y-S) nanostructures is reported. The Fe3O4@N-C@Pd C-S nanostructures were synthesized by two different methods. The first method included two steps: (i) the annealing treatment of the Fe2O3@polydopamine (PDA) under a gas mixture of Ar/H-2 flow and (ii) the decorating Pd NPs on the surface of annealed structures by sodium borohydride as a reducing reagent. The second method, the in-situ reduction of Fe2O3 and Pd2+ in the structure of Fe2O3@PDA@Pd2+ by annealing treatment under H-2 flow as a reducing reagent led to Fe3O4@N-C@Pd C-S nanostructure. Additionally, the Y-S nanostructures were synthesized by using a HCl solution as an effective etching reagent to the partially etch the Fe3O4. Four types of Pd-based catalysts were tested in the selective reduction of p-nitrophenol (p-NP) to p-aminophenol (p-AP). Different catalytic activities were obtained through these catalysts. Furthermore, the reduction of nitroarenes and the oxidation of benzylic alcohols were also studies. (C) 2018 Elsevier Inc. All rights reserved.