Molybdenum sulphide incorporated flexible poly(vinylidene fluoride) nanocomposites for energy harvesting and water remediation by dye degradation via piezocatalysis

Molybdenum sulphide (MoS₂) was incorporated into poly(vinylidene difluoride) (PVDF) matrix via melt-mixing followed by solution casting, to prepare PVDF/MoS₂ nanocomposite films with varying MoS₂ concentration. Piezoelectric properties of PVDF/MoS₂ nanocomposites were significantly boosted by incorporation of MoS₂ in PVDF by aiding in the formation of polar phase in the PVDF/MoS₂ nanocomposites. Formation of electroactive phases in PVDF/MoS₂ nanocomposites was analyzed through Fourier transform infrared and Raman spectroscopic analyses, which also highlighted the interactions between MoS₂ and PVDF dipoles. A remarkable polar phase content of ~97% was achieved in the PVDF/3 MoS₂ nanocomposite (containing 3 wt% MoS₂). Dielectric and ferroelectric investigations further supported the enhancement of interfacial polarization in PVDF/MoS₂ nanocomposite films. Piezoelectric response of the fabricated devices was subsequently assessed, demonstrating an output voltage of ~96 V generated through human-hand actuation on the PVDF/3 MoS₂ nanocomposite film. Additionally, the fabricated device exhibited a substantial volumetric power density of ~150 μW/cm² and a current density of ~7.2 μA/cm². Notably, the optimized PVDF/MoS₂ nanocomposite film exhibited significant degradation efficiencies of ~69.7% and ~67.4% in case of Methylene Blue and Rhodamine B dye, respectively. The successful fabrication of a piezocatalytic PVDF/MoS₂ nanocomposite film provided valuable insights into the piezoelectric response for the degradation of various dyes. Highlights: Self-polarized PVDF/MoS₂ nanocomposite with high polar phase content (∼97%) has been achieved via melt-mixing followed by solution casting. High d₃₃ value of ~72 pm/V was achieved in the PVDF/3 MoS₂ nanocomposite. PVDF/3 MoS₂ nanocomposite based piezoelectric nanogenerator can generate an output voltage of ~96 V under 3 N with sensitivity of ~26 V/N. Power density of ~150 μW/cm² and current density of ~7.2 μA/cm² were obtained. PVDF/3 MoS₂ nanocomposite film acted as an effective piezocatalysts for the degradation of organic dye with >69% efficiency.