Effect of surface loading and bulk doping of La3+ on the thermal stability and photocatalytic activity of Bi2O2CO3

Abstract

The Bi2O2O3 modified La3+ was synthesized using two methods of co-precipitation (La-Bi2O2O3) and wet impregnation (La/Bi2O2O3). The effects of the above two modification methods on the stability of Bi2O2CO3 after calcination and the physicochemical properties of Bi2O2CO3 were investigated by XRD, SEM, BET, and XPS. As compared with La-Bi2O2O3, it is observed that Bi2O2CO3 can be effectively stabilized by impregnation method, as La3+ is mainly dispersed onto the surface of Bi2O2O3. The photocatalytic activities for the methyl orange degradation for the La/Bi2O2CO3 and the La-Bi2O2CO3 samples were tested, and the results showed that surface doping (impregnation method) is benefit for the improvement in the photocatalytic activity, as compared with bulk doping (coprecipitation method). PL characterization revealed the differences in the photocatalytic process for surface doping and bulk doping. The surface modification of La3+ greatly suppresses the charge recombination of photogenerated electron−hole pairs in Bi2O2CO3, which would be beneficial to improve their photocatalytic activity.