Sustainable paper templated ultrathin, light-weight and flexible niobium carbide based films against electromagnetic interference

A novel and sustainable paper template-based method was developed for the fabrication of advanced niobium carbide (NbC)-based free-standing films for electromagnetic interference (EMI) shielding application. Through employing the porous structure of paper template, the simultaneous optimization of thickness, flexibility, density and shielding effectiveness (SE) of NbC-based films was facilely achieved. The pyrolytic carbon (PyC) derived from paper worked as a carbon source for the growth of the NbC phase. A hierarchically porous structure with a porosity of ∼80 vol % was established to optimize the flexibility and density of the resultant films. Adjusted heterogeneous NbC-PyC nano-interfaces were formed by controlling the amount of NbC and the remaining PyC phase in the films, which significantly improved the absorption capability of EM waves. At the highest NbC content, the film possesses shielding effectiveness of 50 and 86 dB when the sample thickness is ∼55 and ∼220 μm, respectively compared to 32 dB of pristine paper-derived PyC film (∼55 μm). These results provide guidance to explore more eco-friendly and commercially effective routes for the recycling of used paper through developing their application in the EM field