Malachite green (MG) dye known for its severe toxicity poses significant health hazards, including risks of cancer, genetic mutations, and respiratory damage. This investigation highlights an eco-friendly, sustainable, economical, and efficient green approach for fabrication of silver oxide-zinc oxide bimetallic nanoparticles (AgO-ZnO BMNPs). The purpose of this study is to optimize the degradation process of MG dye under light exposure. To achieve this, we successfully prepared biogenic AgO-ZnO BMNPs crystals. The compositions, structures, morphologies, and optical behavior of these BMNPs were analyzed by UV–vis, SEM, XRD, EDX and FTIR techniques. AgO-ZnO BMNPs showed absorption peaks by UV–vis analysis at 215, 289 nm for silver and at 219, 278 nm for zinc. XRD analysis showed the crystal size of AgO-ZnO BMNPs was 10 nm determined by the Scherrer equation. The results revealed that the AgO-ZnO BMNPs degrade 95 % MG dye in 40 min at pH 10 using 300 mg/L dose. The antimicrobial ability of AgO-ZnO BMNPs was assessed against harmful bacterial strains. The results revealed that these BMNPs have good inhibition potential against all tested strains. The AgO-ZnO BMNPs exhibit high photocatalytic efficiency and strong antimicrobial potential, indicating their effectiveness in degrading pollutants and combating harmful bacteria. The comprehensive results suggest that these green-synthesized AgO-ZnO BMNPs hold significant potential for use in versatile applications.

Samarium-doped nickel oxide (NiO-Sm) nanoparticles (NPs) were synthesized using Raphanus sativus leaf extract as a green reducing and capping agent. NiO nanoparticles showed a characteristic UV–Vis absorption peak at 220 nm with additional bands at 280–322 nm, while Sm doping induced a bathochromic shift to 230 nm and FTIR confirmed metal-oxygen bonding (Sm-O and Ni-O). XRD analysis revealed NiO as the dominant phase with minor cubic Sm₂O₃ features, and SEM images showed irregular, agglomerated nanoparticles with porous, loosely packed structures in the nano-to-micron range. The Photocatalytic activity of malachite green (MG) dye was optimized using Response Surface Methodology (RSM), with three factor Box-Behnken design, evaluating the effects of reaction time, pH, and catalyst dosage. Under optimized conditions (75 min, pH 8, and 30 mg/L catalyst) the NiO-Sm NPs achieved 99% degradation efficiency, in good agreement with the predicted 98% (desirability = 1.0). Statistical validation using ANOVA confirmed the model’s reliability with a high F value (49.90), (p < 0.0001), and strong correlation coefficients R² = 0.9201, adjusted R²d = 0.9017, predicted R² = 0.8336). The enhanced degradation potential under alkaline conditions was due to increased hydroxyl radical generation and favorable electrostatic interactions between the negatively charged catalyst surface and cationic dye molecules. In addition to photocatalysis, NiO-Sm NPs exhibited promising electrochemical sensing for ascorbic acid detection. These findings demonstrate the NiO-Sm NPs as a dual functional nanomaterial with excellent potential for environmental remediation of organic pollutants as well as electrochemical sensing applications.