The effect of potassium chloride on BiVO4 morphology and photocatalysis

The monoclinic BiVO4 was synthesized via a facile one-pot hydrothermal synthesis. KCl concentration in the precursor greatly influences the crystal growth, morphology, and absorption properties of BiVO4 attributed to the effect of Clˉ ions on the formation of BiOCl intermediate and preferential growth of BiVO4 crystals along {010} planes. The photocatalytic property of BiVO4 is accordingly altered based on the KCl content. The “shuriken-like” BiVO4 prepared with 3 ​mmol of KCl exhibits the highest photocatalytic activity among our samples. Its photocatalytic rhodamine B degradation efficiency could reach 94.7% after 4 ​h of visible-light irradiation. The degradation efficiency only decreased to 90.8% after four runs of 4 h irradiation. The photodegradation rate with the shuriken-like BiVO4 is around 2.3 times higher than that with the rod-like BiVO4 prepared without KCl, owing to its highest relative intensity ratio of (040) to (1¯21) plane, which maximizes the exposed active {010} facets of BiVO4.