摘要
通过缺位填充法合成了分子式为α2 -K8[P2 W1 7PdⅡOH2 ]O61 的钯 (Ⅱ )取代Dawson型十八钨磷酸盐 .在玻碳电极 (GC)上 ,用电化学方法将单取代Dawson型杂多酸盐α2 -K8[P2 W1 7PdⅡOH2 ]O61 的阴离子 (P2 W1 7Pd)掺杂到聚吡咯 (PPy)薄膜中制成P2 W1 7Pd/PPy/GC化学修饰电极 ,实验观察到一对氧化还原峰 ,归属于P2 W1 7Pd中的钯原子 .P2 W1 7Pd/PPy/GC既保持该杂多酸的电化学活性和电催化性能 ,又具有良好的稳定性和灵敏度 .研究表明 ,0 .1 0mol·L- 1 H2 SO4(pH3 .0 ,2 0℃ )溶液中 ,聚吡咯薄膜中P2 W1 7Pd的还原峰对NO-2 的电还原具有良好的催化活性 ,其催化电流与NO-2 浓度在 1 .0 0× 1 0 - 6～ 2 .5 0×1 0 - 5 mol·L- 1 (2 0℃ )范围内呈良好的线性关系 ,检测下限为 5 .0 0× 1 0 - 7mol·L- 1 ,相关系数为 0 .991 0 .文中将P2 W1 7Pd/PPy/GC用作电化学检测器对模拟水样进行了回收率测定 (95 .6 %～ 97.5 % ) 。
The Dawson type heptadecatungstodiphosphate substituted by Pd(Ⅱ) with the formula α 2-K 8[P 2W 17Pd ⅡOH 2]O 61(P 2W 17Pd) was prepared by vacant refilling method.The anion of single substituted Dawson-type tungstophosphate salt P 2W 17Pd was doped into the polypyrrole (PPy) film on a glass carbon electrode (GC) by electrochemical method to prepare the chemically modified electrode (P 2W 17Pd/PPy/GC).A pair of redox waves was observed on the P 2W 17Pd/PPy/GC,which is ascribed to the redox process of the Palladium center in the heteropolytungstate.This modified electrode not only maintains the electrochemical activity and electrocatalytic property of P 2W 17Pd,but also has good stability and sensitivity.In 0.10?mol·L -1 H 2SO 4 solution(pH3.0,20℃),the anodic peak of P 2W 17Pd doping in polypyrrole film can catalyze well the electroreduction of nitrite.The catalytic current is proportional to the concentration of nitrite from 1.00×10 -6 to 2.50×10 -5?mol·L -1(at 20℃) with a correlation coefficient of 0.991?0 and detection limit is 5.0×10 -7?mol·L -1.The P 2W 17Pd/PPy/GC was applied successfully as anelectrochemical detector (ECD) to determine the nitrite level in artificial water sample with the recovery rate of 95.6%-97.5%.The mechanisms of the catalytic reactions were also addressed.
出处
《云南大学学报（自然科学版）》
CAS
CSCD
2001年第6期447-453,共7页
Journal of Yunnan University(Natural Sciences Edition)
