Fabrication of brookite@anatase heterojunction TiO2via phase transformation from metal organic frameworks for enhanced photocatalytic hydrogen evolution and TCH degradation

Abstract

A heterophase junction TiO₂ catalyst with brookite and anatase (MT-200-BA) was prepared via a facile one-step solvothermal method, based on the initial construction of the MIL-125(Ti) metal organic framework (MOF) precursor and subsequent structure transformation from the MOF precursor to brookite@anatase heterojunction TiO₂. The fabricated catalysts have been fully characterized by X-ray diffraction (XRD), N₂ adsorption–desorption, thermogravimetry (TG), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), electron paramagnetic resonance (EPR) and various spectral and electrochemical tests. It was found that the unique nanostructure with a high specific surface area and large pore diameter, particularly brookite@anatase heterophase junctions and a narrow band gap make the MT-200-BA catalyst exhibit a significantly enhanced solar-driven H₂ generation rate under air mass 1.5 global (AM 1.5 G), which is significantly higher than those of MIL-125(Ti), MT-180-MA and commercial P25. In addition, the MT-200-BA catalyst has also shown excellent photocatalytic performance for the degradation of tetracycline hydrochloride (TCH). The synthesis strategy adopted in this paper paves a new way for the construction of novel photocatalysts with heterojunctions via phase transformation from MOFs.