Oriented cobalt-ferrite nanoparticles in flexible polymer film for sustainable energy harvesting and water remediation applications

The energy crisis and water pollution are the pressing issues in surveillance that need an urgent solution. Here, we improvise the existing fabrication of nanocomposites of poly-vinylidene fluoride (PVDF) with cobalt ferrite (CFO) nanoparticles by aligning CFO nanofillers. While employed as an active material for triboelectric nanogenerator, the magnetically aligned 20wt % CFO nanocomposite film has the highest response in nanogenerator application, achieving ~22 V of open-circuit voltage, nearly 7.6 times that of the pristine PVDF film and ~1.54 times that of nanocomposites prepared in the absence of magnetic field. The decrease in the highest polarizable polymorph of PVDF i.e β-phase beyond 20wt% of CFO reduces the voltage and current generation. The reduction in the generated voltage and current was not affecting the piezocatalysis, rather the dye degradation monotonically increases. This was elaborated as combined effect of polarization and cavitation bubbles collapsing. Additionally, the magnetically aligned composite shows a superior piezocatalytic activity to both the cationic and anionic dyes with a removal percentage of 85 % for Crystal Violet and ~84 % for Congo Red. The plausible mechanism for the power generation and the dye degradation by the magnetically oriented nanocomposites is discussed. The investigations indicate the great potential of multifunctional oriented nanoparticles/PVDF composite in harvesting the mechanical energy and the degradation of toxic organic pollutants for water purification.