Fabrication of p-type BiOCl/n-type La2Ti2O7 facet-coupling heterostructure with enhanced photocatalytic performance

Abstract

In this study, highly active p–n-type BiOCl/La₂Ti₂O₇ facet-coupling heterostructured nanocomposites were prepared via a simple method. The as-obtained samples were characterized by multiple techniques, such as scanning electron microscopy (SEM), transmission electron microscopy and high resolution transmission electron microscopy (TEM, HRTEM), X-ray diffraction (XRD), UV-vis diffuse reflectance spectrometry (DRS) and nitrogen adsorption–desorption testing. The photocatalytic activity of as-prepared BiOCl/La₂Ti₂O₇ nanocomposites was investigated by degradation of the dye, rhodamine B, under UV light irradiation. The results revealed that BiOCl/La₂Ti₂O₇ nanocomposites exhibited much higher photocatalytic activity compared to pure La₂Ti₂O₇. In addition, BiOCl/La₂Ti₂O₇ nanocomposites with BiOCl content of 22 wt% possessed the best photocatalytic properties. Furthermore, photocurrent measurements, electrochemical impedance spectroscopy (EIS) and photoluminescence (PL) spectra were applied to study the mechanism of increased photocatalytic activity. The obtained results revealed that BiOCl/La₂Ti₂O₇ heterojunction nanocomposites displayed better separation efficiency of photogenerated charge carriers and higher transfer rates of electrons in the interfacial domain due to the synergistic effect of {002}/{200} facet-coupling and p–n-type heterojunctions formed between BiOCl nanoplates and La₂Ti₂O₇ thin nanosheets.