10.1016/j.jcis.2014.08.027
A controlled anion exchange strategy to synthesize core-shell β-bismuth oxide/bismuth sulfide hollow heterostructures with enhanced visible-light photocatalytic activity
 All chemical reagents in our experiments were analytical and used as received without further purification. The synthesis of β-Bi2O3 hollow spheres adopted our previous method [21]. In a typical experiment, Bi(NO3)3*5H2O (2.91 g, 6 mmol) was dissolved in a mixed solution of glycerol (30 mL) and ethanol (30 mL) under vigorous stirring. After 40 min of stirring, the solution was transferred to a 100 mL Teflon-lined stainless steel autoclave, heated to 160 degC and maintained for 3 h. After the autoclave was cooled to room temperature, the products were separated centrifugally and washed with deionized water and absolute ethanol for several times, and then dried under vacuum at 80 degC overnight. Finally, the products were further heated at 2 degC/min heating rate from room temperature to 270 degC and maintained at 270 degC for 2 h to obtain β-Bi2O3 hollow spheres. 
The core/shell β-Bi2O3/Bi2S3 hollow heterostructure was synthesized by in situ anion-exchange method. In a typical process, the as-prepared β-Bi2O3 hollow microsphere (0.4660 g, 1 mmol) was dispersed in 50 mL deionized water under vigorous stirring. Then a certain amount CH3CSNH2 (0.0225 g, 0.3 mmol) was added into the solution. After 30 min of stirring at 50 degC, the precipitates were collected, washed and dried under vacuum at 80 degC for 6 h. By controlling the theoretical molar percentage of Bi2S3 to initial Bi2O3, different β-Bi2O3/Bi2S3 heterostructures were obtained. The final samples were labeled as the β-Bi2O3/Bi2S3 (5%, 10%, 25%) heterostructure.
Bi(NO3)3*5H2O
dissolved
2.91 g
g
Bi(NO3)3*5H2O
dissolved
6 mmol
mmol
glycerol
stirring
30 mL
mL
ethanol
stirring
30 mL
mL
solution
stirring
40 min
min
Teflon-lined stainless steel autoclave
100 mL
mL
solution
heated
160 degC
degC
solution
maintained
3 h
h
products
dried
80 degC
degC
products
heating rate
2 degC/min
degC/min
products
maintained
270 degC
degC
products
heated
270 degC
degC
products
maintained at 270 degC
2 h
h
β-Bi2O3 hollow microsphere
dispersed
0.4660 g
g
β-Bi2O3 hollow microsphere
dispersed
1 mmol
mmol
deionized water
50 mL
mL
CH3CSNH2
added
0.0225 g
g
CH3CSNH2
added
0.3 mmol
mmol
precipitates
stirring
30 min
min
precipitates
stirring
50 degC
degC
precipitates
dried under vacuum
80 degC
degC
precipitates
dried under vacuum
6 h
h
β-Bi2O3/Bi2S3
labeled
5%, 10%, 25%
%