Synthesis of Bi2S3/BiVO4 Heterojunction with a One-Step Hydrothermal Method Based on pH Control and the Evaluation of Visible-Light Photocatalytic Performance
Deqiang Zhao,
Wenwen Wang,
Wenjuan Zong,
Shimin Xiong,
Qian Zhang,
Fangying Ji,
Xuan Xu
Affiliations
Deqiang Zhao
Key Laboratory of Three Gorges Reservoir Region’s Eco-Environment Ministry of Education and National Centre for International Research of Low-Carbon and Green Buildings, Chongqing University, No. 174 Shazhengjie, Shapingba, Chongqing 400045, China
Wenwen Wang
Faculty of Urban Construction and Environment Engineering, Chongqing 400045, China
Wenjuan Zong
Key Laboratory of Three Gorges Reservoir Region’s Eco-Environment Ministry of Education and National Centre for International Research of Low-Carbon and Green Buildings, Chongqing University, No. 174 Shazhengjie, Shapingba, Chongqing 400045, China
Shimin Xiong
Key Laboratory of Three Gorges Reservoir Region’s Eco-Environment Ministry of Education and National Centre for International Research of Low-Carbon and Green Buildings, Chongqing University, No. 174 Shazhengjie, Shapingba, Chongqing 400045, China
Qian Zhang
Key Laboratory of Three Gorges Reservoir Region’s Eco-Environment Ministry of Education and National Centre for International Research of Low-Carbon and Green Buildings, Chongqing University, No. 174 Shazhengjie, Shapingba, Chongqing 400045, China
Fangying Ji
Key Laboratory of Three Gorges Reservoir Region’s Eco-Environment Ministry of Education and National Centre for International Research of Low-Carbon and Green Buildings, Chongqing University, No. 174 Shazhengjie, Shapingba, Chongqing 400045, China
Xuan Xu
Key Laboratory of Three Gorges Reservoir Region’s Eco-Environment Ministry of Education and National Centre for International Research of Low-Carbon and Green Buildings, Chongqing University, No. 174 Shazhengjie, Shapingba, Chongqing 400045, China
The band gaps of bismuth vanadate (BiVO4) and bismuth sulfide (Bi2S3) are about 2.40 eV and 1.30 eV, respectively. Although both BiVO4 and Bi2S3 are capable of strong visible light absorption, electron–hole recombination occurs easily. To solve this problem, we designed a one-step hydrothermal method for synthesizing a Bismuth sulfide (Bi2S3)/Bismuth vanadate (BiVO4) heterojunction using polyvinylpyrrolidone K-30 (PVP) as a structure-directing agent, and 2-Amino-3-mercaptopropanoic acid (l-cysteine) as a sulfur source. The pH of the reaction solution was regulated to yield different products: when the pH was 7.5, only monoclinic BiVO4 was produced (sample 7.5); when the pH was 8.0 or 8.5, both Bi2S3 and BiVO4 were produced (samples 8.0 and 8.5); and when the pH was 9.0, only Bi2S3 was produced (sample 9.0). In sample 8.0, Bi2S3 and BiVO4 were closely integrated with each other, with Bi2S3 particles formed on the surface of concentric BiVO4 layers, but the two compounds grew separately in a pH solution of 8.5. Visible-light photocatalytic degradation experiments demonstrated that the degradation efficiency of the Bi2S3/BiVO4 heterojunction was highest when prepared under a pH of 8.0. The initial rhodamine B in the solution (5 mg/L) was completely degraded within three hours. Recycling experiments verified the high stability of Bi2S3/BiVO4. The synthesis method proposed in this paper is expected to enable large-scale and practical use of Bi2S3/BiVO4.
