One-Pot Electrochemical Preparation and Performance of BiOCl0.5Br0.5/BiPO4 Double-Layer Heterojunction Thin Film Photocatalyst

BiOCl0.5Br0.5/BiPO4 double-layer heterojunction thin film photocatalyst was successfully prepared on Bi plate by one-pot electrochemical method. The crystal structure, elemental composition and valence, morphology and optical property were characterized. The as-obtained double-layer film consisted of BiOCl0.5Br0.5 solid solution layer at the bottom and BiPO4 nanoparticles layer at the top. The interface internal electric field of BiOCl0.5Br0.5/BiPO4 composite film led the photo-induced electrons and holes to shift in the opposite direction, thus improving the photocatalytic performance of BiOCl0.5Br0.5/BiPO4 composite film. The results displayed that the photodegradation efficiency of phenol reached 99.97% after 120 min under simulated sunlight irradiation, which was nearly 1.69 times and 1.20 times more than that of BiOCl/BiPO4 and BiOBr/(BiPO4) composite films, respectively. Besides, the hole (h(+)) and hydroxyl radical (center dot OH) played a crucial role in the photodegradation process of phenol. The improved photocatalytic performance of BiOCl0.5Br0.5/BiPO4 composite film can be ascribed to the broadened absorbance spectra range and efficient separation of photo-induced charge carriers.