Fabrication of β-phase AgI and Bi2O3 co-decorated Bi2O2CO3 heterojunctions with enhanced photocatalytic performance

Bi 2 O 2 CO 3 was co-decorated by β-phase AgI and Bi 2 O 3 forming visible-light-active AgI(β)/Bi 2 O 3 (β)-Bi 2 O 2 CO 3 composite via simply calcining AgI/Bi 2 O 2 CO 3 . The calcination temperature and time played vital role in regulating the structure as well as photocatalytic performance. Optimal AgI(β)/Bi 2 O 3 (β)-Bi 2 O 2 CO 3 was obtained after 325  ◦ C calcination for 2 h with 5% AgI. The ratio of Bi 2 O 3 to Bi 2 O 2 CO 3 was estimated to be ca. 3:1 on the catalyst surface. The transformation process for n -type Bi 2 O 2 CO 3 to p-type Bi 2 O 3 (β) was monitored and verified by flat band potential measurements. Due to the presence of p-n junctions between p-type Bi 2 O 3 (β), n -type AgI(β) and Bi 2 O 2 CO 3 , the optimized ternary composite displayed enhanced photocurrent density and reduced charge transfer resistance, which were beneficial for photocatalytic applications. Despite of decreased specific surface area, dramatically enhanced photocatalytic performance can be observed for simultaneous removal of Cr(VI) and phenol . For example, the estimated k Cr(VI) and k phenol on AgI(β)/Bi 2 O 3 (β)-Bi 2 O 2 CO 3 were 3.3 and 2.2 times relative to those on uncalcined AgI/Bi 2 O 2 CO 3 , respectively. The optimized composite also displayed good stability in 4 successive cyclic runs.