A new p-n heterojunction CuO–Ag2WO4 supported on Ni foam as an efficient photocatalyst in the synthesis of some 2-substituted benzimidazoles, as effective antibacterial drugs

Abstract

2-substituted benzimidazoles are important pharmaceuticals with a wide range of therapeutic activities and because of their antibacterial potential against many pathogenic bacteria including Gram-positive and Gram-negative bacteria including Klebsiella pneumoniae. This study unveils a new strategy for addressing environmental issues and global energy through the in-situ photocatalytic oxidation of benzyl alcohols to benzaldehydes, followed by the synthesis of a variety of 2-substituted benzimidazoles by the presence of CuO–Ag₂WO₄–Ni foam p-n heterojunction photocatalyst. This innovative photocatalyst demonstrates unparalleled catalytic performance, facilitating the synthesis of benzimidazoles in remarkably high yields via condensation with o-phenylenediamine. Utilizing an extensive suite of characterization techniques including X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDX), field emission scanning electron microscopy (FESEM), UV–Vis diffuse reflectance spectroscopy (DRS), and Mott-Schottky analysis, revealed the structural robustness and distinctive nanostructure of the catalyst. Under the illumination of a green laser (λ 535 nm) in an aqueous environment, the CuO–Ag₂WO₄–Ni foam exhibited extraordinary stability and reusability, coupled with ease of separation from reaction mixture. The unique morphology of the foam, characterized by a highly porous architecture and expanded surface area, plays a critical role in enhancing photocatalytic activity by promoting effective charge separation and transfer mechanisms. The proposed photocatalytic mechanism is driven by reactive species, including superoxide radicals (•O₂⁻) and hydroxyl radicals (OH•), along with photogenerated holes (h⁺). Electrochemical impedance spectroscopy (EIS) and Mott-Schottky analyses elucidate the intricacies of charge transport dynamics and semiconductor properties intrinsic to the photocatalyst. The minimal leaching of catalytic species during repeated catalytic cycles underscores its practical viability for industrial applications.