SYNTHESIS AND CHARACTERIZATION OF Ag/Mn2O3 NANOCOMPOSITES AND THEIR APPLICATION AS HETEROGENOUS CATALYST FOR REDUCTION OF NITROPHENOLS

Abstract

Metal/Metal oxide nanocomposites are important in nanoscience, and their synthesis has piqued the interest of today and world scientists due to their many uses in supercapacitors, waste water treatment, and energy storage, among others. In this report, synthesis of Mn2O3 nanoparticles has reported by single step thermal decomposition method. Further, three Ag/Mn2O3 nanocomposites were synthesised with different amounts of Ag represented as AM-5 (5% Ag), AM-10 (10% Ag), and AM-15 (15% Ag). To characterize the Mn2O3 and Ag/Mn2O3 nanocomposites various techniques were used such as Powder XRD (X-ray diffraction), FT-IR (fourier transform infrared spectroscopy), FE-SEM (field emission scanning electron microscopy) and XPS (X-ray photoelectron spectroscopy). The catalytic reduction of nitrophenols was used to evaluate the catalytic activity of all the synthesised samples. Different catalytic tests were carried out, including a comparison of all catalysts, a change in catalyst dose, a change in NaBH4 concentration, and a change in 4-NPh concentration. AM-15 was the most effective catalyst among all of them as it reduced 4-NPh in 6.5 min and AM-10, AM-5 reduced 4-NPh in 8 min, and 11 min, respectively. The order of reduction of different nitrophenols is as follows: 3-NPh> 4-NPh> tri-NPh > 2-NPh by using 30 μL of AM-15 catalyst (from 1 mg/mL). The efficiency of AM-15 as a catalyst was also investigated by reducing dye bath effluent (a real industrial effluent sample) and EFF (a simulated industrial sample). Reusability of catalyst was also tested by repeatedly using AM-15 for reduction of 4-NPh up to five cycles.