and 0.4800 g distilled water (2.67 ꢃ 10ꢁ2 mol) under vigorous
stirring. The mixture was heated to 60 1C and stirred for about
10 min until a clear solution was obtained. Then 0.3 g of
PMo12 (1.3 ꢃ 10ꢁ3 mole) was added to the cooled mixture
followed by 1.5 g of deionized water (0.83 mol), and the blend
was mixed up to total dissolution of PMo12 (about 10 min).
After that, yellow transparent monolithic pieces were obtained
by placing the mixture in the dark (avoiding light irradiation)
at ambient temperature for 15–18 h.
successively and washed with purified water before use. Soni-
cation of the polished electrode appeared to have no effect on
the resulting responses. Electrochemistry measurements were
conducted in 0.5 M H2SO4. A bare glassy carbon electrode
was respectively immersed in 1 ꢃ 10ꢁ3 M of PMo12 aqueous
solution and PMo12-containing sol, and allowed to stand for
2 h. Then the electrode was taken out and rinsed with
deionized water, and the resulting electrode was transferred
to 0.5 M H2SO4.
The H2S and SO2 gases were prepared in our laboratory.
H2S was prepared in terms of the reaction H2SO4 + FeS -
H2S + FeSO4 and dried by CaCl2. SO2 was prepared by the
reaction H2SO4 + Na2SO3 - SO2 + Na2SO4 + H2O and
dried by CaCl2. All chemicals were purchased from Sino-
pharm Chemical Reagent Beijing Co., Ltd. All reagents were
analytical grade and used without further purification. The
water used in all experiments was deionized to a resistivity of
18 MO.
Acknowledgements
The authors are thankful for the financial supports from the
National Natural Science Foundation of China (Grant No.
20671017; 20731002) and the Specialized Research Fund for
the Doctoral Program of Higher Education.
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ꢂc
This journal is The Royal Society of Chemistry and the Centre National de la Recherche Scientifique 2008 New J. Chem., 2008, 32, 1008–1013 | 1013