Co@C nanorods as both magnetic stirring nanobars and magnetic recyclable nanocatalysts for microcatalytic reactions

The rapid and effective mixing of reactants and catalysts is essential in liquid-phase catalytic reaction to boost mass transport. However, the routinely used magnetic stirring method is impractical for ultra-small systems such as lab-on-chip and flow cell due to the macroscale size of the magnetic bars. Herein, we developed a facile strategy to synthesize catalytically active magnetic Co@C nanorods, which could serve as both high-performance catalysts and magnetic stirring nanobars for micro-catalytic reactions. The Co@C core-shell structure endows the materials with high catalytic activity and excellent durability, while the strong magnetism of Co nanoparticles renders the nanorod catalyst unique stirring capability under an external rotating magnetic field, which significantly promotes the mass transport and also the catalytic efficiency in micro-catalytic reactions. Inspired by the unique structure and properties, the mixing ability and catalytic activity of Co@C nanorods were evaluated in several systems. A cobalt nanoparticles embedded in 1D graphitic carbon (Co@C) nanorods catalyst with high catalytic activity and superior saturation magnetization is reported. The obtained Co@C nanorods play a bifunctional role as both high-performance catalyst and nanoscale stirring bars, which showed great potentials for microcatalytic systems, demonstrated by using catalytic reduction of 4-nitrophenol to 4-aminophenol by NaBH 4 and Fenton-like reaction for methylene blue (MB) degradation at room temperature as probe reactions. • A facile strategy to build 1D magnetic Co@C nanorods as both nano-stirring bars and nanocatalysts for micro systems. • Co@C nanorods promote the generation of 1 O 2 and lead to a high Fenton-like reaction performance in a flow cell. • Co@C exhibits both outstanding mixing ability and catalytic activity in a 40 μL ultra-small microdroplet.