Solanum tuberosum tuber-driven starch-mediated green-hydrothermal synthesis of cerium oxide nanoparticles for efficient photocatalysis and antimicrobial activities

Abstract

In this study, we are reporting for the first time the utilization of Solanum tuberosum tuber-driven, starch-mediated, green-hydrothermally synthesized cerium oxide nanoparticles (G-CeO₂ NPs) for the antibacterial activity and photodegradation of cationic (methylene blue, MB) and anionic (methyl orange, MO) dyes separately and in combination, aimed at environmental remediation. The XRD analysis confirms the fluorite structure of G-CeO₂ NPs, displaying an average crystallite size of 9.6 nm. Further, XPS confirms the existence of 24% of Ce³⁺ oxidation states within G-CeO₂ NPs. Morphological studies through FE-SEM and TEM reveal that starch-driven OH^- ion production leads to a high percentage of active crystal facets, favoring the formation of Ce³⁺-rich CeO₂ NPs. Photocatalytic experiments conducted under UV-A illumination demonstrate the superior degradation performance of G-CeO₂ NPs, with MB degradation reaching 93.4% and MO degradation at 77.2% within 90 min. This outstanding catalytic activity is attributed to the mesoporous structure (pore diameter of 5.63 nm) with a narrow band gap, a large surface area (103.38 m²g^-1), and reduced charge recombination, as validated by BET, UV-visible, and electrochemical investigations. The identification of photogenerated intermediates is achieved through LCMS, while the mineralization is monitored via total organic carbon analysis. Moreover, the scavenging experiments point towards the involvement of reactive oxygen species in organic oxidation, demonstrating efficiency over five consecutive trials. Additionally, G-CeO₂ NPs exhibit potent antibacterial activity against both gram-positive and gram-negative bacteria. This study presents an innovative, and efficient approach to environmental remediation, shedding light on the potential of G-CeO₂ NPs in addressing environmental pollution challenges.

Keywords: Bacterial pathogens; Cerium oxide; Environmental remediation; Green hydrothermal synthesis; Nanoparticles; Photocatalysis.