An in situ synthesis of a new nanocomposite, polyaniline/manganese dioxide/ titanium dioxide (PANI/MnO 2 /TiO 2 ), via a one-pot oxidative polymerization method at room temperature is described in this article. The characterization was done on the synthesized nanocomposite using UV−vis, FT-IR, XRD, TGA, SEM, and TEM analysis. A superior catalytic activity is exhibited by the synergistic PANI/MnO 2 /TiO 2 nanocomposite in the conversion of toxic Cr 6+ to benign Cr 3+ in comparison with PANI, MnO 2 , TiO 2 , PANI/MnO 2 , PANI/TiO 2 , MnO 2 /TiO 2 , and other nanocomposite materials reported. The reduction rate is dependent on the concentration of substrate (Cr 6+ ), oxidant (HCOOH), and catalyst, pH, temperature, and foreign ions. The PANI/MnO 2 /TiO 2 reveals an excellent conversion (99.9%), rate constant (15.97 × 10 −2 min −1 ), and turnover frequency (0.3333 mmol/mg/min) in the reduction of Cr 6+ . The results obtained from this study illustrate that the prepared nanocomposite, PANI/MnO 2 /TiO 2 , can be very well used as an effective and economically viable catalyst for the reduction of toxic contaminant Cr 6+ from wastewater.

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A simple and very sensitive electrochemical sensor for the detection of uric acid (UA) has been developed based on polyaniline (PANI) merged into a silver-doped iron oxide (Ag-FeO) nanocomposite-modified glassy carbon electrode. The synthesized ternary composite material (Ag-FeO@PANI) was characterized by UV-visible spectroscopy, Fourier transform infrared spectroscopy, energy-dispersive X-ray, High-resolution transmission electron microscopy, X-ray diffraction, and thermo gravimetric analysis analyses. The nanocomposite-modified electrode shows an exceptional electrocatalytic activity and reversibility to the oxidation of UA in a 0.1 M phosphate buffer solution (pH 7.0) compared to those in PANI and Ag-FeO. The detection limit of UA is found to be 102 pM with a linear dynamic range of 0.001-0.900 μM. The fabricated UA sensor also exhibits good selectivity, reproducibility, and long-time stability. The limit of detection and linear range attained for the synthesized composite are much greater compared to those of any other composite materials reported in the literature. The proposed method has been successfully applied for the selective detection of UA in various real samples such as human serum and urine with good recoveries. This platform that assimilates such electrocatalytic ternary nanocomposite with high performance can be widely employed for fabricating diverse sensors.

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A rapid way to dedye industrial effluents is reported herein using silver nanoshells (Ag-NSs) as a green catalyst.