Comparison of catalytic and fuel additive properties of bimetallic nanoparticles and its composite: FeMnO₃ and PANI-FeMnO₃

A novel nanocomposite polyaniline-iron manganese oxide (PANI-FeMnO₃) is successfully synthesized via in-situ chemical oxidative polymerization of aniline using ammonium persulfate (APS) as an oxidizing agent and FeMnO₃ bimetallic nanoparticles. FeMnO₃ bimetallic nanoparticles are prepared by a temperature-controlled solvothermal method to obtain desired morphology. The morphology of synthesized products is confirmed by SEM and STEM analysis. XRD analysis provided that bimetallic nanoparticles are highly crystalline however, nanocomposites have amorphous nature due to the presence of polymer. FTIR patterns of PANI and PANI-FeMnO₃ nanocomposite have characteristic peaks at 1543 cm^-1, indicating the electron delocalization in the conductive emeraldine form of PANI. Catalytic efficiency of the FeMnO₃ bimetallic nanoparticles and PANI-FeMnO₃ nanocomposites as catalysts in organic dyes and nitroarenes reduction is studied. Different parameters such as k_app, reduction time, percentage reduction and reduced concentration are performed to assess the catalytic activity of both catalysts. Among all substrates, highest k_app value is 0.186 min^-1 for 2,4-DNP with PANI-FeMnO₃ nanocomposite. Effect of type and orientation of functional groups, nature of bonds and steric hindrance on the reduction rate of substrates is also studied. The efficiency of FeMnO₃ bimetallic nanoparticles and PANI-FeMnO₃ nanocomposite as nano additives is also evaluated and compared by investigating the physical and combustion parameters of commercial diesel. Fuel efficiency is observed to be greatly enhanced by increasing the dosage of nano additives. The results indicate that the efficiency of PANI-FeMnO₃ nanocomposite is greater than that FeMnO₃ bimetallic nanoparticles.