Photoelectrochemical properties of sol-gel synthesized titanium dioxide nano-particles using different acids: X-ray photoelectron spectroscopy reveals the induced effect of hydrolysis precursor

Properties such as crystalline structure (X-ray diffraction - XRD), surface chemistry-electronic states (X-ray photoelectron spectroscopy - XPS), morphology and particle size-distribution (Transmission Electron Microscopy - TEM), electronic structure-band-gap (UV-vis spectroscopy) and surface area (BET-nitrogen physisorption) were analyzed for titanium dioxide (TiO₂)-semiconductor-surfaces synthesized by sol-gel route using nitric, acetic and phosphoric acids as hydrolysis precursors. According to XRD analysis, it was established that anatase phase has been obtained with a particle size linked to the acid of hydrolysis employed (i.e. dissociation constant), as also demonstrated by TEM and area BET. On the other hand, using XPS, a shift toward lower binding energies was observed from TiO₂obtained using HNO₃promoting some structural modification and the reduction in the band-gap, inducing a better faradic current-performance by decreasing charge-transfer resistance during polarization and at induced-generated photocurrent using UV-light.