Constructing core@shell SiO₂@C-Au multicomponent nanocomposites to enhance conduction and polarization loss capabilities for microwave absorption and antimicrobial

Conduction and/or polarization loss play a key role in improving electromagnetic wave (EMW) absorption. In this work, a combined polymerization and high-heat treatment process was utilized to efficiently fabricate core@shell structure SiO₂@C adopting SiO₂ nanospheres as a hard template. The acquired SiO₂@C nanocomposites displayed unsatisfied EMW absorption performances with minimum reflection loss value of −34.92 dB at 6.35 mm, and effective absorption bandwidth value of 3.20 GHz at 4.83 mm, respectively. In order to further comprehensively boost its microwave absorption performances (MAPs), a facile self-assembly strategy was adopted to load Au nanoparticles on the outer surface of SiO₂@C nanospheres, constructing core@shell SiO₂@C-Au multicomponent nanocomposites (MCNCs). By regulating the volume of Au nanoparticles, different Au contents of SiO₂@C-Au MCNCs could be selectively produced in high efficiencies. The obtained outcomes demonstrated that the SiO₂@C-Au MCNCs presented improved properties including EMW attenuation, impedance matching, conduction loss and polarization loss with increasing the content of Au nanoparticles. Thanks to the introduction of conductive Au nanoparticles and excellent interfacial effects, the SiO₂@C-Au MCNCs presented the greatly improved antimicrobial and EMW absorption performances including strong absorption, wide bandwidth and small thicknesses. Consequently, this finding offered a novel strategy to construct core@shell SiO₂@C-Au MCNCs, which simultaneously boosted conduction and polarization loss capabilities for EMW absorption.