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The use of magnetic nanoparticles in C–C coupling reactions enables the facile recovery of the catalyst under environmentally friendly conditions. Herein, the synthesis of Pd/Fe@Fe3O4 nanoparticles by the reduction of Pd2+ and oxidation of Fe on the surface of preformed Fe@Fe3O4 is reported. The nanoparticles were characterized using a variety of analytical techniques (transmission electron microscopy, Mössbauer spectroscopy, X-ray photoelectron spectroscopy, and X-ray diffraction) to determine their size, structure, and chemical composition. The catalytic efficiency of these nanoparticles in classical Suzuki–Miyaura coupling reactions was investigated. The nanoparticles achieved high catalytic activity with the application of local heating by an alternating magnetic field. An investigation was conducted at identical temperatures to compare global heating with the application of an external magnetic field; magnetic heating demonstrated excellent substrate conversion in lesser time and at a lower temperature. The catalyst could also be recycled and reused three times, with ~ 30% decrease in the substrate conversion, which is most likely due to the agglomeration of the Pd nanoparticles or poisoning of the Pd catalyst. This approach, which takes advantage of the catalytic activity and magnetic susceptibility of magnetic nanoparticles, can be applied to several organic transformations to improve their efficiency, We are grateful for financial support provided by the Government of Spain through project PGC2018-095642-B-I00. In addition, A. Villacampa and L. Duque acknowledge the Community of Madrid for Predoctoral contracts PEJD-2019-PRE/IND-15356 and PEJ-2019-AI/IND-12506, respectively, co-financed by the European Social Fund through the Youth Employment Operational Program and the Youth Employment Initiative (YEI)

One-dimensional (1D, wire- and fiber-shaped) supercapacitors have recently attracted interest due to their roll-up, micrometer size and potential applications in portable or wearable electronics. Herein, a 1D wire-shaped electrode was developed based on Fe3O4 nanosheet arrays connected on the Fe wire, which was prepared via oxidation of Fe wire in 0.1 M KCl solution (pH 3) with O2-rich environment under 70 °C. The obtained Fe3O4 nanosheet arrays displayed a high specific capacitance (20.8 mF cm−1 at 10 mV s−1) and long cycling lifespan (91.7% retention after 2500 cycles). The excellent performance may attribute to the connected nanosheet structure with abundant open spaces and the intimate contact between the Fe3O4 and iron substrate. In addition, a wire-shaped asymmetric supercapacitor was fabricated and had excellent capacitive properties with a high energy density (9 µWh cm−2) at power density of 532.7 µW cm−2 and remarkable long-term cycling performance (99% capacitance retention after 2000 cycles). Considering low cost and earth-abundant electrode material, as well as outstanding electrochemical properties, the assembled supercapacitor will possess enormous potential for practical applications in portable electronic device.