Innovative development of hybrid nanocatalyst (ATH-ZnONPs) through green methods for achieving visible light-induced photocatalytic aerobic oxidation of benzyl alcohols into corresponding aldehydes and ketones

Abstract

In recent research, there has been a surging interest in green methods for manufacturing metal oxide photocatalysts and enabling organic transformations in gentle conditions. This study achieved a groundbreaking development, introducing zinc oxide nanoparticles sensitized with anthocyanin dye (ATH-ZnONPs) for the very first time. The reducing agents in pomegranate leaves were utilized to synthesize ZnONPs from zinc salt. Simultaneously, anthocyanin dye was extracted from pomegranate flowers and linked with the ZnONPs. The FT-IR functional group analysis provided evidence of the successful conjugation of ZnONPs and ATH dye. SEM, EDX, and Elemental Mapping analysis unveiled the spherical morphology and nanocrystalline structure of ATH-ZnONPs, with particle sizes falling within the range of 50–70 nm. XRD analysis verified the hexagonal structural configuration of ZnONPs within the hybrid nanocomposite, with calculated lattice parameters of a = 3.261 Å and c = 5.207 Å. UV–Vis and DRS spectroscopy demonstrated that the composite efficiently harnesses visible light irradiation, exhibiting an energy bandgap of 2.22 eV. The assessment of ZnONPs through BET analysis unveiled a pore volume of 0.053 cm3/g, an SSA of 14.223 m2/g, and an average pore size of 4.18 nm, underscoring the mesoporous characteristics of ZnONPs. Importantly, the photocatalytic performance of the synthesized ATH-ZnONPs was thoroughly examined under blue LED light exposure. This investigation encompassed the evaluation of catalyst dosage, the impact of the light source, stability, regeneration, and the potential for reuse in the aerobic oxidation of benzyl alcohols, resulting in their corresponding aldehydes and ketones. 1HNMR and 13CNMR were used to characterize the products. The results of these studies highlight the versatile potential of this composite for a wide range of photocatalytic applications.