Core-Shell Vanadium Modified Titania@β-In₂S₃ Hybrid Nanorod Arrays for Superior Interface Stability and Photochemical Activity

Core-shell rutile TiO₂@β-In₂S₃ and modified V-TiO₂@β-In₂S₃ were synthesized to develop bilayer systems to uphold charge transport via an effective and stable interface. Morphological studies revealed that β-In₂S₃ was deposited homogeneously on V-TiO₂ as compared to unmodified TiO₂ nanorod arrays. X-ray photoelectron spectroscopy (XPS) and electron energy loss spectrometry studies verified the presence of various oxidation states of vanadium in rutile TiO₂ and the vanadium surface was utilized for broadening the charge collection centers in host substrate layer and hole quencher window. Subsequently, X-ray diffraction, high-resolution transmission electron microscopy, and Raman spectra confirmed the rutile phases of TiO₂ and modified V-TiO₂ along with the phases of crystalline β-In₂S₃. XPS valence band study explored the interaction of valence band quazi Fermi levels of β-In₂S₃ with the conduction band quazi Fermi levels of modified V-TiO₂ for enhanced charge collection at the interface. Photoelectrochemical studies show that the photocurrent density of V-TiO₂@β-In₂S₃ is 1.42 mA/cm² (1.5AM illumination). Also, the frequency window for TiO₂ was broadened by the vanadium modification in rutile TiO₂ nanorod arrays, and the lifetime of the charge carrier and stability of the interface in V-TiO₂@β-In₂S₃ were enhanced compared to the unmodified TiO₂@β-In₂S₃. These findings highlight the significance of modifications in host substrates and interfaces, which have profound implications on interphase stability, photocatalysis and solar-fuel-based devices.