Synthesis of ZnO semiconductor nanoparticles using extracts of Capsicum annuum L. for photocatalytic activity in degradation of polluting dyes

In this work, ZnO semiconductor nanoparticles were green-synthesized using Capsicum annuum L. var. Caribe pepper extracts at 1%, 2%, and 4% w/v (weight/volume) as stabilizing agents. The nanoparticles were applied in photocatalytic processes for the degradation of Methylene Blue (MB), Methyl Orange (MO), and Rhodamine B (RhB) in aqueous media. Characterization involved Fourier Transform Infrared Spectroscopy (FTIR), identifying the Zn-O bond at 421 cm-1. X-Ray Diffraction (XRD) analysis revealed a hexagonal Wurtzite-type crystalline phase with crystallite sizes ranging from 13 to 23 nm. Scanning Electron Microscopy (SEM) showed hemispherical clusters smaller than 5 micrometers. UV–Visible spectrophotometry determined band gap values between 3.05 and 3.13 eV. These materials exhibited significant photocatalytic degradation efficiency for the tested dyes.