Thermochemical method of synthesizing stemmed nanoflower TiO2/eC3N4 heterojunction structures with enhanced solar water splitting

TiO 2 nanoflower array linking to stem on a Ti foil is synthesized by thermochemical digestion of titanium at 80 °C by hydrogen peroxide and hydrofluoric acid solution. TiO 2 nanoflower comprised of the anatase TiO 2 which encased Ti metal core as seen by transmission electron microscopy (TEM), x-ray Photoelectron Spectroscopy based depth profiling, x-ray diffraction (XRD) analysis, and energy dispersive x-ray based elemental mapping. The TEM, selected area electron diffraction, and XRD analysis of air annealed TiO 2 nanoflower show presence of anatase (101) and anatase (200) crystals of about 35 nm size. The Photoelectrochemical activity in water splitting is assessed for heterojunction formed by the TiO 2 nanoflower with exfoliated carbon nitride (eC 3 N 4 ), and the same is compared with heterojunction of TiO 2 nanotubular array and eC 3 N 4 . It was found from linear sweep voltammetry and electrochemical impedance spectroscopy that the synthesized stemmed-nanoflower TiO 2 offers superior PEC activity towards water splitting when used in heterojunction with eC 3 N 4 as compared to that of TiO 2 nanotube with eC 3 N 4 .