Facile fabrication of Au-loaded CdO nanoconstructs with tuned properties for photocatalytic and biomedical applications

Abstract

Cadmium oxide (CdO) had long been investigated for decades as prototypical wide-band-gap transparent conducting oxides (TCOs) possessing excellent n-type ability having its implications in the field of photo electronics. Despite this, there exists an uncertainty on the toxicity of CdO content during the synthesis and product retrieval which limits their use in biological applications. In this context, an approach to enhance the inbuilt properties of CdO particles by the means of loading (in coating form) with gold (Au) nanoparticles (NPs) to generate Au@CdO nanoconstructs (NCs) has been reported. Thus, formed Au@CdO NCs have been characterized by various spectroscopic and electron microscopic analysis for the structural, optical, and biological properties. For example, the UV–Vis spectroscopy revealed a typical λmax of CdO at 302 nm, and for the Au@CdO, a shift toward 496 nm was observed. The diffraction pattern demonstrated the crystalline phase corresponding to (1 1 1) plane with mean grain sizes of 24.9 and 30.6 nm for the CdO and Au@CdO, respectively. The FTIR and optical studies highlighted the intermolecular bonding with an increased bandgap confirming the efficient coating of Au onto CdO. The FESEM demonstrated spherical-to-elliptical-shaped anisotropic particles following the coating of CdO with Au and the grain size getting increased from 30 to 42 nm. On testing of the photocatalytic activity, we found that the Au@CdO NCs efficiently degraded the Rhodamine B dye (96% in 180 min) following the irradiation under artificial UV light. Furthermore, the Au@CdO NCs showed a significant antimicrobial effect at 80 μg/mL associated with a decline in the cell count. Alongside, the IC50 of Au@CdO against A549 and PBMC cells was fixed at 46.87 and 55.14 μg/mL, respectively. Such multifaceted Au@CdO NCs possessing optical properties might present themselves as the potential candidates for the extended photocatalytic and biomedical applications.