Synthesis of Indium Borate and Its Application in Photodegradation of 4-Chlorophenol

Indium borate has been prepared by a sol-gel method. The structure, morphology, and photophysics of the resultant photocatalysts have been studied via the techniques of X-ray diffraction (XRD), transmission electron microscopy (TEM), and diffuse reflectance UV-visible light spectroscopy. These photocatalysts have been used to photodegrade 4-chlorophenol. The photocatalytic activity depends on the annealing temperature during preparation. It is found that borates can exhibit a high photodegradation activity under UV-light irradiation, for which the efficiency can be higher than that of as-prepared TiO2. This is explained according to the results of fluorescence spectra and valence band X-ray photoelectron spectroscopy (XPS). It is confirmed by the results of time-resolved photoluminescence decay spectra; i.e., the lifetime of electrons and holes involved in the radiative process can be longer for the borates than that for TiO2. This implies that indium borate can be a promising photocatalyst for future applications in treatment of environment contaminants.