Synthesis of novel poly(1‐naphthylamine)‐silver nanocomposites and its catalytic studies on reduction of 4‐nitrophenol and methylene blue

Poly(1-Napthylamine) Nanoparticles as Potential Scaffold for Supercapacitor and Photocatalytic Applications

Herein, we explore the supercapacitor and photocatalytic applications of poly(1-naphthylamine) (PNA) nanoparticles. The PNA nanoparticles were synthesized by using polymerization of 1-naphthylamine and characterized with several techniques in order to understand the morphological, structural, optical and compositional properties. The structural and morphological properties confirmed the formation of crystalline nanoparticles of PNA. The Fourier-transform infrared (FTIR) spectrum revealed the successful polymerization of 1-naphthylamine monomer to PNA. The absorption peaks that appeared at 236 and 309 nm in the UV−Vis spectrum for PNA nanoparticles represented the π−π* transition. The supercapacitor properties of the prepared PNA nanoparticles were evaluated with cyclic voltammetry (CV) and galvanostatic charge−discharge (GCD) methods at different scan rates and current densities, respectively. The effective series resistance was calculated using electrochemical impedance spectroscopy (EIS), resulting in a minimum resistance value of 1.5 Ω. The highest specific capacitance value of PNA was found to be 255 Fg−1. This electrode also exhibited excellent stability with >93% capacitance retention for 1000 cycles, as measured at 1A g−1. Further, the prepared PNA nanoparticles were used as an effective photocatalyst for the photocatalytic degradation of methylene blue (MB) dye, which exhibited ~61% degradation under UV light irradiation. The observed results revealed that PNA nanoparticles are not only a potential electrode material for supercapacitor applications but also an efficient photocatalyst for the photocatalytic degradation of hazardous and toxic organic dyes.

Highly efficient degradation of metronidazole drug using CaFe2O4/PNA nanohybrids as metal-organic catalysts under microwave irradiation

Catalytic degradation based on microwave irradiation is an emerging technique which promises prompt and efficient catalytic degradation of organic pollutants. Calcium ferrite (CaFe₂O₄), poly(1-napththylamine) (PNA), and PNA/CaFe₂O₄ nanohybrids were synthesized via microwave-assisted technique. The properties of the as-prepared CaFe₂O₄, PNA, and PNA/CaFe₂O₄ nanohybrids were characterized by the thermogravimetric analysis (TGA), FTIR, XRD, SEM, and ultraviolet-visible spectrophotometry (UV-vis) analyses. The formation of inorganic-organic hybrids was confirmed by the FTIR and XRD studies. Loading of PNA was confirmed to be 8%, 16%, 32%, and 40% in CaFe₂O₄ which was established by TGA studies and the thermal stability was found to follow the order: CaFe₂O₄ > 8-PNA/CaFe₂O₄ > 16-PNA/CaFe₂O₄ > 32-PNA/CaFe₂O₄ > 40-PNA/CaFe₂O₄ > PNA. CaFe₂O₄ and PNA revealed band gap values of 3.42 eV and 2.60 eV respectively while for the PNA/CaFe₂O₄ nanohybrids, the values were found to be ranging between 2.46 and 3.00 eV. The PNA modified CaFe₂O₄ nanohybrids showed higher degradation efficiency towards metronidazole (MTZ) drug as compared with PNA and pure CaFe₂O₄. MTZ drug showed around 94% degradation within 21 min of microwave irradiation using 40-PNA/CaFe₂O₄ as catalyst. The enhanced catalytic activity was attributed to the high surface area of the nanohybrid catalyst as well as improved microwave catalytic activity of PNA. The reactive species responsible for degradation were confirmed by scavenger studies which formation of ^·OH and O₂^·- radicals. Recyclability tests showed that the 40-PNA/CaFe₂O₄ nanohybrid exhibited 86% degradation of MTZ (90 mg/l) even after the third cycle, which reflected higher reusability of the catalyst. The MTZ fragments were identified using liquid chromatography-mass spectrometry (LC-MS).