A breakthrough sustainable synthesis of Er₂O₃ nanoparticles using Dendrocalamus asper natural extract for effective photocatalytic response

This study presents a novel, safe, and eco-friendly method for synthesizing Erbium Oxide (Er₂O₃) nanoparticles (NPs). We used Dendrocalamus asper leaf extract (EDA) as a natural precursor, confirming its rich content of secondary metabolites like alkaloids, flavonoids, tannins, saponins, and polyphenols. These compounds play vital roles: alkaloids act as a weak base for synthesis, while others serve as capping agents, ensuring stable nanoparticle formation. Characterization confirmed successful synthesis. Fourier-Transform Infrared Spectroscopy (FT-IR) spectroscopy showed a distinctive Er-O bond vibration at 565.43 cm⁻¹. X-ray diffraction (XRD) analysis revealed a cubic crystalline structure, and UV-Vis Diffuse Reflectance Spectroscopy (DRS) indicated a broad bandgap of 5.2 eV. Scanning electron microscopy (SEM) images displayed spherical, aggregated NPs, and further confirmed their nanoscale size, averaging 21.83 nm. These results collectively affirm the excellent structural, optical, and morphological properties of the synthesized Er₂O₃ NPs. The photocatalytic performance was outstanding. Using malachite green as a model pollutant, the Er₂O₃ NPs achieved a 93.03 % degradation within 120 min under UV light. This degradation followed pseudo-first-order kinetics, with a rate constant (k_obs​) of 1.98 × 10⁻² min⁻¹. The optimized conditions, determined at an initial pH of 6.6, achieved a remarkable 93.03 % degradation. Scavenger experiments were performed to elucidate the mechanism, confirming that the superoxide radical (⋅O₂⁻) is the dominant reactive species responsible for the degradation. Furthermore, the photocatalyst exhibited excellent operational stability, maintaining 85.15 % degradation efficiency even after four consecutive reuse cycles. This research highlights a simple, cost-effective, and efficient green synthesis method for producing highly effective Er₂O₃ NPs, offering a promising solution for environmental remediation.