Enhanced photoelectrochemical water splitting with TiO 2@Ag 2O nanowire arrays via p-n heterojunction formation

摘要

AbstractNanostructured TiO2@Ag2O p-n heterojunction arrays were fabricated by combining the hydrothermal method with the chemical-bath method, and they were used as a photoelectrode in photoelectrochemical (PEC) cell for high-performance solar water splitting. To investigate the morphology, microstructure and composition, the pristine TiO2nanowire arrays (TiO2NWAs) and the TiO2nanowires decorated with Ag2O nanoparticles (TiO2@Ag2O NWAs) were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and electrochemical impedance spectra (EIS). Nanostructured TiO2nanowire arrays were assembled with Ag2O nanoparticles, producing a large number of nano p-n heterojunctions. The TiO2@Ag2O p-n heterojunction arrays showed a photocurrent density of 1.61mA/cm2at 1.23V vs. a reversible hydrogen electrode (RHE) in 0.5M Na2SO4electrolyte under simulated AM 1.5 illumination (100mW/cm2), two times higher than that of the pristine TiO2NWAs. The enhancement was attributed to the efficient electron-hole separation because of the p-n heterojunction interface between p-Ag2O and n-TiO2, which were revealed by the electrochemica