Synergistic enhancement of photoelectrochemical water splitting by Ag and Zn nanoparticle-decorated TiO2 nanorods

Ag and Zn nanoparticles coated on TiO₂ nanorods represent an approach for improving photoelectrochemical water splitting. The synthesis of TiO₂ nanorod arrays embellished with Ag and Zn co-catalyst nanoparticles is reported in this work. X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), energy-dispersive X-ray spectroscopy (EDS), atomic force microscopy (AFM), UV–Vis spectroscopy, linear sweeping voltammetry (LSV), and chronoamperometric measurements were used to evaluate the modified TiO₂ photoelectrode. XRD results confirmed the formation of pure rutile phase in the tetragonal crystal system. The nanorods morphology was confirmed by the FESEM and AFM measurements. EDS analysis verified the presence of requisite elements in weight and atomic percentages. UV–Vis data showed a narrowing of the energy bandgap and an increase in absorbance intensity in the ultraviolet region upon the addition of Ag and Zn nanoparticles. The optical bandgap was significantly reduced from 2.98 eV to 2.71 eV after the Ag and Zn nanoparticles were incorporated. Photoeletrochemical investigations for all samples revealed strong photocurrent density and good light responsiveness under light-operated conditions. The Ag/TiO₂ photoelectrode demonstrated superior performance, achieving a peak photocurrent density of 495 μA/cm² at 1.2 V vs. Ag/AgCl. This is 14 times higher than the 35 μA/cm² recorded for pristine TiO₂.