Optimization of Copper Oxide Nanoparticle Synthesis Using Factorial Experimental Design: Influence of Key Parameters on Particle Size and Morphology

Introduction. The development of advanced nanomaterials is crucial for various technological applications, particularly in biomedical and catalytic fields. Among metal oxide nanoparticles, copper oxide (CuO) nanoparticles (NPs) have garnered significant attention due to their intrinsic bioactivity, including antimicrobial and anti-inflammatory properties. The physicochemical characteristics of CuO NPs are highly dependent on their synthesis parameters, requiring precise control over particle size, morphology, and surface properties. This study aims to optimize the synthesis of CuO NPs using experimental design methodologies to establish a mathematical model correlating synthesis parameters with nanoparticle characteristics. Materials and Methods. CuO NPs were synthesized using precipitation and coprecipitation methods, with Cu(NO3)2 and copper chloride (CuCl2) as precursors, and (NaOH) as a precipitating agent. The experimental design considered three key parameters: synthesis method, calcination temperature (250–450°C), and maturation time (24–48 hours). The synthesized nanoparticles were characterized using Fourier Transform Infrared Spectroscopy (FTIR) for functional group analysis, Scanning Electron Microscopy (SEM) for morphological assessment, and laser granulometry for particle size distribution. A full factorial (2³) experimental design was employed to evaluate the influence of synthesis parameters on nanoparticle size and establish a predictive mathematical model. Results and Discussion. The synthesized CuO NPs exhibited fine black powders with characteristic Cu-O stretching vibrations (400–800 cm⁻¹) in FTIR spectra, confirming their successful formation. SEM analysis revealed spherical and tetrahedral morphologies, with particle sizes ranging between 20 and 60 nm. Factorial analysis identified the synthesis method and calcination temperature as the most influential parameters affecting particle size, while maturation time had a negligible impact. The factorial model equation accurately predicted particle size variations, with the experimental results showing strong agreement with the predicted values (mean deviation < 5.5%). The combination of precipitation synthesis and a calcination temperature of 450°C yielded the smallest CuO NPs, demonstrating an optimized approach for their production. Conclusion. This study highlights the critical role of synthesis parameters in tailoring CuO NP properties. The factorial experimental design effectively optimized the synthesis process, providing a reliable mathematical model for predicting nanoparticle size. These findings contribute to the advancement of CuO NPs for biomedical and industrial applications, with precipitation synthesis at high calcination temperatures emerging as the most effective strategy for producing smaller, well-defined nanoparticles.