Solvothermal Growth of MWCNT-Supported Co/Ag/N-Doped Ternary ZnO Nanocomposite with Altered Band Gap for Visible Light Active Photocatalyst for Environmental Remediation Application

This study investigates the photocatalytic properties of carbon nanotube (CNT)-supported nitrogen-, cobalt-, and silver-doped zinc oxide (ZnO) synthesized via the solvothermal method. Various characterization techniques, including X-ray photoelectron spectroscopy (XPS), BET surface area analysis, energy-dispersion X-ray (EDX) spectroscopy, UV–visible spectroscopy (UV–Vis), scanning electron microscopy (SEM), X-ray diffraction (XRD), photoluminescence (PL), Fourier transform infrared (FTIR), and transmission electron microscopy (TEM), were employed. Photoluminescence spectroscopy revealed lattice defects and the doping effect on ZnO’s electron–hole recombination. FTIR spectroscopy identified functional groups, and EDX and XPS confirmed the presence of Ag, Co, C, Zn, O, and N. XRD and TEM estimated crystal sizes between 21 and 24 nm. UV–Vis spectroscopy showed a reduced band gap from 3.18 to 2.40 eV. SEM images depicted hexagonal nanoparticle structures. BET analysis showed a Category 4 adsorption isotherm and a pore diameter of 8.527 nm. The nanocomposite ZnO exhibited significant photocatalytic degradation under visible light, achieving 96