Designing intimate porous Al2O3 decorated 2D CdO nano-heterojunction as enhanced white light driven photocatalyst and antibacterial agent.

• Mesoporous γ-Al 2 O 3 coupled 2D hexagonal CdO nanoplates as photocatalyst • Prepared using ultrasonic assisted method with good crystallinity • Tailored bandgap energy of CdO/Al 2 O 3 was 2.95 eV with visible light sensitization • Photodegradation of synthetic cationic dye followed first order kinetics • The particles exhibited excellent antibacterial activity The mesoporous network of γ-Al 2 O 3 ceramic support was coupled with the two dimensional (2D) hexagonal CdO nanoplates by ultrasonic assisted method. The fabricated photocatalyst was analyzed for its structural, morphological and optoelectrical properties by employing X-ray photoelectron spectroscopy (XPS), high-resolution transmission electron microscopy (HRTEM), photoluminescence, electron spin resonance (ESR) analysis and electrochemical impedance spectroscopy (EIS). The X-ray powder diffraction (XRD) result supports the good crystallinity of the fabricated nanohybrid with co-existence of pure phases of γ-Al 2 O 3 and CdO nanoparticles (NPs). The nanohybrid was tailored to narrow down the bandgap to visible-light region. The bandgap energy obtained by UV–visible diffuse reflectance spectroscopy (DRS) for CdO/Al 2 O 3 nanocomposite (NCs) was 2.95 eV. The Brunauer-Emmett-Teller (BET) surface area analysis shows porosity of material with high surface area. During photocatalysis, e- from CdO migrates to defect levels of Al 2 O 3 that facilitated charge separation. The kinetic rate of degradation of methylene blue (MB) by NCs was 3.5 and 14 times higher than CdO and Al 2 O 3 respectively. The performance was optimized and it showed good reusability. In addition, the multiple applications of the CdO/Al 2 O 3 were evaluated by testing the bactericidal activity. The nanohybrid posed high growth inhibition activity towards both gram positive and negative bacterial strains. The maximum colour removal (97.3%) and high mineralization (87%) was verified by UV–visible and total organic carbon (TOC) measurements. This promotes the nanohybrid to act as a better candidate for environmental remediation and disinfectant applications. [ABSTRACT FROM AUTHOR]