CuAlO2/Bi2WO6: A novel p-n type composite with significantly enhanced visible-light photocatalytic reduction of Cr(VI)

Abstract

The Bi2WO6 and CuAlO2 powders were synthesized through the method of solid-state reaction. This study prepared the newly and highly effective p-n type CuAlO2/Bi2WO6 photocatalysts that had diverse CuAlO2 compositions by employing an environmentally friendly and economical approach. X-ray powder diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy(SEM), photoluminescence (PL) emission spectra, and UV-vis diffuse reflectance spectroscopy were adopted to characterize the photocatalysts. The as-synthesized CuAlO2/Bi2WO6 heterocatalyst was utilized to reduce toxic Cr (VI) ions into Cr (III) by means of photoreduction under visible light irradiation. When CuAlO2(1.0 wt.%)/Bi2WO6 was used, the Cr (VI) photoreduction rate constant was 4.7 times as many as that of pure Bi2WO6. The study also investigated how the ball milling time and CuAlO2 composition affected the performance of CuAlO2/Bi2WO6. In addition, the stability of composite was investigated. The results revealed that the high conductivity of CuAlO2, excellent crystalline quality, and the p-n heterojunction between CuAlO2 and Bi2WO6 exerted a vital role in enhancing the photoreduction performance. This work explores the design of other new heterocatalysts, especially the p-n type composites containing CuAlO2.