Synergistic effect of Ti3+ doping and facet regulation over Ti3+-doped TiO2 nanosheets with enhanced photoreactivity

Abstract

Ti³⁺-doped TiO₂ nanosheets with different percentages of exposed {001} facets were synthesized by aluminium (Al) reduction. The structure, crystallinity, morphology, and other properties of the as-prepared samples were characterized by X-ray diffraction, transmission electron microscopy, high-resolution transmission electron microscopy and X-ray photoelectron spectroscopy. Electron paramagnetic resonance spectra confirm the presence of paramagnetic Ti³⁺ species in the prepared Ti³⁺-doped TiO₂. Under UV-visible light irradiation, all the Al-reduced TiO₂ nanosheet samples exhibit higher photocatalytic hydrogen evolution, degradation of methyl orange (MO) and photoelectrochemical (PEC) performance than the non-reduced ones. The Al-TiO₂-HF6 sample with the highest Ti³⁺ concentration and optimal exposed {001} facets exhibits the most excellent photoreactivity, which is mainly ascribed to the efficient transport and separation of photo-induced charge carriers resulting from the synergistic effects between Ti³⁺ doping and facet regulation.