A facile approach for the preparation of NiONPs@MnO2NRs nanocomposite material and its photocatalytic activity

Herein, a facile approach for preparing nickel oxide nanoparticles coupled with manganese oxide nanorods (NiONPs@MnO 2 NRs) was reported for the first time. The nickel oxide nanoparticles, manganese oxide nanorods, and nanocomposite material were prepared using simple and inexpensive co-precipitation, hydrothermal, and sonication methods. The structural integrity of the composite materials was interrogated using field emission scanning electron microscopy (FESEM), energy-dispersive X-ray spectroscopy (EDS), transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, and ultraviolet–visible (UV–vis DRS) spectroscopy. FESEM and TEM results revealed an attachment of NiONPs onto the surface of MnO 2 NRs. Electrochemical techniques, which included cyclic voltammetry (CV), linear sweep voltammetry (LSV), and electrochemical impedance spectroscopy (EIS), were employed to interrogate the electrochemical signature of the nanocomposite. The results revealed that these materials are potential nanomediator for the immobilisation of electroactive species in electrocatalysis and electrochemistry. Upon applying the materials in the photocatalytic degradation of 10 mg L −1 bromophenol blue dye, NiONPs@MnO 2 NRs gave an efficiency of 81.5%, which was 2.8 and 4.3 folds higher than those obtained with NiONPs and MnO 2 NRs materials, respectively. The electrochemical characterisation results confirmed an increased separation of electron–hole pairs, which helped enhance the photocatalytic activity of the composite material. The results further indicate that the prepared composite material can be explored with other organic water pollutants such as pesticides and pharmaceuticals. Graphical abstract