Ni-Pd-Incorporated Fe3O4 Yolk-Shelled Nanospheres as Efficient Magnetically Recyclable Catalysts for Reduction of N-Containing Unsaturated Compounds

The use of metal-based heterogeneous catalysts for the degradation of N-containing organic dyes has attracted much attention due to their excellent treatment efficiency and capability. Here, we report the synthesis of heterometals (Ni and Pd)-incorporated Fe3O4 (Ni-Pd/Fe3O4) yolk-shelled nanospheres for the catalytic reduction of N-containing organic dyes using a facile combination of solvothermal treatment and high-temperature annealing steps. Benefiting from the magnetic properties and the yolk-shelled structure of the Fe3O4 support, as well as the uniformly dispersed active heterometals incorporated in the shell and yolk of spherical Fe3O4 nanoparticles, the as-prepared Ni-Pd/Fe3O4 composite shows excellent recyclability and enhanced catalytic activity for three N-containing organic dyes (e.g., 4-nitrophenol, Congo red, and methyl orange) compared with its mono metal counterparts (e.g., Ni/Fe3O4 and Pd/Fe3O4). In the 4-nitrophenol reduction reaction, the catalytic activity of Ni-Pd/Fe3O4 was superior to many Fe3O4-supported nanocatalysts reported within the last five years. This work provides an effective strategy to boost the activity of iron oxide-based catalytic materials via dual or even multiple heterometallic incorporation strategy and sheds new light on environmental catalysis.

Automated summary

This study reports the synthesis of Ni-Pd/Fe3O4 composite nanospheres by incorporating heterometals into Fe3O4 shell and yolk, which exhibit excellent treatment efficiency and capability for the degradation of N-containing organic dyes. The as-prepared composite shows enhanced catalytic activity and recyclability compared to its mono metal counterparts. In addition, it demonstrates superior catalytic activity in the reduction of 4-nitrophenol. This work provides a new strategy to enhance the activity of iron oxide-based catalytic materials and contributes to environmental catalysis research.