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

摘要

Bi2O2CO3 was co-decorated by beta-phase AgI and Bi2O3 forming visible-light-active AgI(beta)/Bi2O3(beta)-Bi2O2CO3 composite via simply calcining AgI/Bi2O2CO3. The calcination temperature and time played vital role in regulating the structure as well as photocatalytic performance. Optimal AgI(beta)/Bi2O3(beta)-Bi2O2CO3 was obtained after 325 degrees C calcination for 2 h with 5% Agl. The ratio of Bi2O3 to Bi2O2CO3 was estimated to be ca. 3:1 on the catalyst surface. The transformation process for n-type Bi2O2CO3 to p-type Bi2O3(0) was monitored and verified by flat band potential measurements. Due to the presence of p-n junctions between p-type Bi2O3(13), n-type AgI(beta) and Bi2O2CO3, the optimized ternary composite displayed enhanced photocurrent density and reduced charge transfer resistance, which were beneficial for photo catalytic 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(beta)/Bi2O3(beta)-Bi2O2CO3 were 3.3 and 2.2 times relative to those on uncalcined AgI/Bi2O2CO3, respectively. The optimized composite also displayed good stability in 4 successive cyclic runs. (C) 2019 Elsevier Inc. All rights reserved.