Synergistic Approach of TiO2@MnZnO3 Heterostructure for Efficient Photoelectrochemical Water Splitting

Abstract

The superior kinetics of charge carriers and greater visible light absorption are important factors for enhancing photoelectrochemical performance. Herein, the core–shell heterostructure has been developed by encapsulating single-phase MnZnO₃ over TiO₂ nanotubes by aerosol-assisted chemical vapor deposition approach. The fabricated photoanodes have been characterized by employing various techniques including X-ray diffraction, Raman spectroscopy, scanning electron microscopy, energy dispersive X-ray spectroscopy, atomic force microscopy, and photoluminescence. Moreover, the mechanism for electron/hole transfer has been focused by a brief electrochemical investigation. The bilayer 1D/2D TiO₂@MnZnO₃ photoanode exhibited higher current density (2 mA cm⁻²) as compared to pristine TiO₂-nanotubes (0.174 mA cm⁻²) at 1.52 V vs RHE. The superior photoactivity of heterostructure is attributed to the rapid transfer of photogenerated charge carriers via the Type-II mechanism. Furthermore, the reduced band gap (2.05 eV) accounts for good absorption in the visible region of light, while the interfacial electric field allowed the improved charge separation. The synergistic strategy in the present work demonstrates the promising significance of a heterojunction interface to optimize photovoltaic devices.