Fabrication of hierarchically porous CuO nanostructures using Brij 52 and silica nanoparticles as reinforcing agents for the reduction of 3-nitroaniline to 3-phenylenediamine and sensing against diclofenac sodium

An environmentally friendly, scalable and facile sol-gel approach with and without dextran was used for the synthesis of copper oxide (CuO) nanocomposites from Brij 52 templates for heterogeneous catalysis and sensing applications. The porous materials were transformed into shape-selective morphologies by using dextran (Dex) and silica nanoparticles (SiNPs) as structural directing agents (SDAs). Fourier transform infrared spectroscopy (FT-IR spectroscopy), powder X-ray diffraction analysis (PX-RD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Brunauer–Emmett–Teller (BET) adsorption analysis, thermogravimetric analysis (TGA) and gas chromatography mass spectrometry (GC-MS) were used to characterize the synthesized nanocomposites. CuO nanocomposites were used as a catalyst to reduce 3-nitroaniline (3-NA) to 3-phenylenediamine in the presence of NaBH₄. CuO nanocomposites were also tested as a sensor against Diclofenac sodium (DS) in phosphate buffer solution at pH 4.0 with retention of limit of detection (LOD) 0.224 ng mL⁻¹ and limit of quantification (LOQ) 0.543 ng mL⁻¹. This whole synthesis is non-toxic, environmentally friendly and economical.