Successive evaluation of the green synthesized rare earth metal oxide CeO2 nanoparticles for the photo-induced degradation of methylene blue and CO2 photoreduction: Optimization of the reaction parameters by RSM-CCD model

Abstract

Background

Environmental pollution, stemming from synthetic dyes like methylene blue and excessive CO₂ emissions, presents an imperative global challenge. Advanced nanomaterials, particularly CeO₂ nanoparticles, have emerged as promising candidates for addressing these issues due to their exceptional photocatalytic properties, chemical stability, and environmentally friendly nature.

Methodology

We report on the green synthesis of CeO₂ nanoparticles and evaluate their potential to degrade methylene blue and photoreduction of CO₂. The surface composition, morphology, size, crystal structure, and surface functional groups of the prepared nanoparticles were determined by Fourier transform infrared spectroscopy, x-ray diffraction, scanning electron microscopy, transmission electron microscopy, x-ray photoelectron spectroscopy, and zeta potential.

Significant findings

The synthesized nanoparticles exhibited an exceptional value of methylene blue degradation, as they displayed a 96.19 % degradation value in an hour. The optimized reaction value obtained from the application of response surface methodology was CeO₂ dosage = 110 mg, MB dosage = 77.9 mg/L, temperature = 50 °C, and agitation speed = 150.003 rpm. Moreover, prepared nanoparticles reduced 109.27 µmol.g⁻¹ h⁻¹ of CO₂ to its byproducts, particularly into CO. These outstanding results hint at the advantageous synthesis of the nanoparticles mentioned above from the green route and present a solution for emerging environmental concerns.