Tunable Multifunctional Composite of Cobalt Ferrite in Flexible Polymer Film for High‐Performance Triboelectric Nanogenerators‐Driven Energy Harvesting and Piezocatalytic Water Remediation

The energy crisis and water pollution are urgent challenges requiring immediate attention and an effective solution. Here, the conventional composite made of poly-vinylidene fluoride (PVDF) and cobalt ferrite (CFO) nanoparticles is advanced by aligning the CFO nanofiller in only one preferred direction. The magnetically aligned 20 wt.% PVDF–CFO composite film has the highest response as a triboelectric nanogenerator, achieving ≈22 V of open-circuit voltage. It is nearly 7.6 times that of the pristine PVDF film and ≈1.54 times that of the composite prepared in the absence of a magnetic field. Crossing 20 wt.% of CFO reduces the voltage and current generation by decreasing the amount of PVDF's β-phase, its highest polarizable polymorph. 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. Obtained results showcase the great potential of multifunctional composites made of oriented nanoparticles embedded in PVDF for harvesting the mechanical energy and decomposing toxic organic pollutants toward water purification.