Preparation and Photocatalytic Activity of ABi₂O₆/BiOCl (A = Mg, Sr, Ca) Heterojunction

Abstract

MgBi 2 O 6 , CaBi 2 O 6 , and SrBi 2 O 6 were successfully synthesized by a substitution reaction of NaBiO 3 with MgCl 2 , CaCl 2 , and Sr(NO 3 ) 2 , respectively. Then, ABi 2 O 6 /BiOCl (A = Mg, Ca, Sr) heterojunction compounds with different ABi 2 O 6 :BiOCl ratios were prepared by treating ABi 2 O 6 with an appropriate amount of HCl. The color of the ABi 2 O 6 /BiOCl heterojunction was changed from dark to bright as the amount of BiOCl was increased. The absorbances of the ABi 2 O 6 /BiOCl heterojunctions in the visible range were decreased as the ratio of BiOCl became higher. The photocatalytic activities of the heterojunction samples were higher than that of sole ABi 2 O 6 or BiOCl. The highest photocatalytic efficiency was achieved when the ABi 2 O 6 :BiOCl ratio was 15:85. The organic pollutant was decomposed completely within 1 h under visible light when the 15:85 catalyst was used. The reactive species in the photocatalytic reaction with the ABi 2 O 6 /BiOCl photocatalysts were ÁO 2 and h + H + .