Fabrication of A/R-TiO ₂ composite for enhanced photoelectrochemical performance: Solar hydrogen generation and dye degradation

Anatase/rutile TiO ₂ nanorods composites were prepared by a facile hydrothermal method followed by dip coating method using titanium isopropoxide in acetic acid and ethanol solvent. The effects of the titanium isopropoxide precursor concentration, on the formation of dip coated anatase/rutile TiO ₂ nanorods composite were systematically explored. The growth of anatase on rutile TiO ₂ nanorods can be controlled by varying the titanium isopropoxide concentration. The morphological study reveals that anatase TiO ₂ nanograins formed on the surface of rutile TiO ₂ nanorod arrays through dip coating method. Photoelectrochemical analyses showed that the enhancement of the photocatalytic activities of the samples is affected by the anatase nanograins present on the rutile TiO ₂ nanorods, which can induce the separation of electrons and holes. To interpret the photoelectrochemical behaviors, the prepared photoelectrodes were applied in photoelectrochemical solar hydrogen generation and orange II dye degradation. The optimized photocurrent density of 1.8 mA cm ⁻² and the 625 μmol hydrogen generation was observed for 10 mM anatase/rutile TiO ₂ NRs composites. Additionally, 96% removal of the orange II dye was achieved within 5 h during oxidative degradation under solar light irradiation. One of the benefits of high specific surface area and the efficient photogenerated charge transport in the anatase/rutile TiO ₂ nanorod composite improves the photoelectrochemical hydrogen generation and orange dye degradation compared to the rutile TiO ₂ . Thus, our strategy provides a promising, stable, and low cost alternative to existing photocatalysts and is expected to attract considerable attention for industrial applications.