Synthesis of a multi-functionalized NiCo2O4 spinel heterostructure via the hydrothermal route for high-performance photo-electrocatalytic, anti-bacterial and eco-toxicity applications

Abstract

The fabrication of a high-yield, reproducible and cost-effective photo-electrocatalyst, i.e., Bi₂O₃/NiCo₂O₄, was investigated via the hydrothermal route. Subsequently, it was decorated with reduced graphene oxide (rGO), semiconducting polyaminoanthraquinone (PAAQ), and hydrotalcite (HTs). The performance of the synthesized catalysts was analyzed for the electrocatalytic oxygen evolution (OER) and photocatalytic degradation of methylene blue, rhodamine B dye and pharmaceutical drugs such as acetaminophen. Subsequently, the Bi₂O₃/NiCo₂O₄ catalyst was characterized via XRD, DRS-UV, FT-IR spectroscopy, TG/DTA, SEM, HR-TEM, XPS and BET analyses. The lowest Tafel slope and overpotential were determined to be 66 mV dec⁻¹ and 329 mV for rGO@Bi₂O₃/NiCo₂O₄ at 10 mA cm⁻². A chronoamperometry test was performed to study the efficient stability and continued oxygen evolution performance of rGO@Bi₂O₃/NiCo₂O₄ at an applied potential of 1.559 V (vs. RHE), demonstrating that it is efficient and stable for the OER and pollutant removal applications. Furthermore, its antibacterial activity against pathogens was evaluated, indicating that it had a significant impact on DNA damage, protein affinity and rapid generation of reactive oxygen species (ROS).