Nickel Oxide Decorated MWCNTs Wrapped Polypyrrole: One Dimensional Ternary Nanocomposites for Enhanced Thermoelectric Performance

This study reports on a customized and revised approach to fabricate “nickel oxide decorated multi-walled carbon nanotubes (MWCNTs) wrapped polypyrrole (PPy)” nanocomposite with enhanced room-temperature thermoelectric (TE) properties. The nanocomposite is formed through three steps: MWCNTs functionalization via diazonium salt grafting of 5-amino-1,2,3-benzene tricarboxylic acid; in situ generation on their surfaces of NiO nanoparticles with a homogenous distribution; the chemical polymerization of pyrrole using methyl orange as templating and dopant to wrap the MWCNTs-(COOH) ₃-NiO. Various techniques were used as characterization tools, including XRD, TEM, FTIR, Raman, TGA, XPS, and TE measurements. The PPy-MWCNTs-(COOH) ₃-NiO nanocomposite exhibits significantly higher Seebeck coefficient, electrical conductivity, and power factor than PPy and PPy-MWCNTs-(COOH) ₃. The achieved enhancement in TE properties (figure of merit, ZT _{PPy-MWCNTs-(COOH)3-NiO}=1.51×10 ⁻²) is attributed to the presence of NiO, which acts as a dopant and improves the charge carrier density in the nanocomposite. These results offer the potential for waste heat recovery and large-scale fabrication of high-performance composites.