Facile synthesis of Cu0.72Co2.28O4–CuO composite nanoparticles grown on HMS sieves: characterization and catalytic evaluation in the reduction of 4-NP

In the present work, Cu_0.72Co_2.28O₄–CuO/HMS nanocomposite was efficiently synthesized by a novel, facile, simple and eco-friendly impregnation method followed by calcination at 550 °C. The Fourier transform infrared spectroscopy and X-ray diffraction results established the formation of the nanocomposite Cu_0.72Co_2.28O₄–CuO/HMS. The catalytic reduction of 4-NP to 4-AP in the presence of excess NaBH₄ as a reducing agent in aqueous media, was selected as a reaction model to evaluate the catalytic activity of Cu_0.72Co_2.28O₄–CuO/HMS nanocomposite in the ambient. The Cu_0.72Co_2.28O₄–CuO/HMS material exhibited robust catalytic activity in 4-NP reduction with a rate constant of \(2.04 \times {10}^{-2}{\text{ s}}^{-1}\). A 4-NP conversion percentage which is of 100% was achieved within 90 s on the nanocomposite. The kinetic analysis confirmed the Langmuir–Hinshelwood model for the Cu_0.72Co_2.28O₄–CuO/HMS material catalyzed 4-NP reduction.