Rapid anchoring of iron-carbon nanoparticles on carbon spheres using microwave heating

Despite excellent performance of iron/carbon materials in microwave absorbing field, the synthesis of these composites faces challenges, involving prolonged processing times and the aggregation of iron nanoparticles. Here, an efficient microwave-induced preparation method is proposed to overcome this problem. First, carbon spheres with uniform particle size were synthesized as support for iron deposition. By employing ultrafast pyrolysis of ferrocene, iron nanoparticles were anchored on the surface of carbon spheres, where a comparative analysis of the microstructure and composition of Fe/C materials synthesized via microwave heating and conventional heating was conducted, alongside a quantitative investigation into the correlation between ferrocene addition and complex dielectric constant. The mechanism of microwave enhancing dispersion of iron particles was elucidated, indicating that microwave induced local overheating of carbon spheres rapidly decomposes ferrocene, facilitating uniform deposition of iron nanoparticles on the carbon sphere surfaces. Consequently, compared with Fe/C materials synthesized via conventional methods, microwave heating improves the dispersion of supported iron nanoparticles, reducing reaction time from hours to 2 min. In addition, an optimal multi-step strategy for promoting the efficient deposition of iron nanoparticles was developed, where a variety of different absorbing materials, the highest real and imaginary parts of which, obtained at 2.45 GHz, were 87.15 and 68.81, respectively. This article is part of the discussion meeting issue ‘Microwave science in sustainability’.