Fabrication of A/R-TiO₂ composite for enhanced photoelectrochemical performance: Solar hydrogen generation and dye degradation

Highlights: • Dip coated A/R-TiO₂ composite strategy using titanium isopropoxide is proposed. • Effective light scattering and improved charge transport improves the PEC performance. • Composite enhances the photocurrent density of A/R-TiO₂ electrods. • A/R-TiO₂ composite achieves hydrogen generation activity of 156.25 μmol/h. • A/R-TiO₂ composite exhibits excellent performance to remove orange (II) dye. - Abstract: Anatase/rutile TiO₂ 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 TiO₂ nanorods composite were systematically explored. The growth of anatase on rutile TiO₂ nanorods can be controlled by varying the titanium isopropoxide concentration. The morphological study reveals that anatase TiO₂ nanograins formed on the surface of rutile TiO₂ 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 TiO₂ 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 TiO₂ 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 TiO₂ nanorod composite improves the photoelectrochemical hydrogen generation and orange dye degradation compared to the rutile TiO₂. Thus, our strategy provides a promising, stable, and low cost alternative to existing photocatalysts and is expected to attract considerable attention for industrial applications.