利用溶膠-凝膠法製備固態高分子電解質之非酵素與高選擇性酒精感測器

Using Sol-Gel Method to Prepare Solid Polymer Electrolyte for Fabrication of High Selectivity And Enzyme Free Alcohol Gas Sensor.

林良諭(Liang-yu Lin)

指導教授 ： 周澤川

大同大學/工程學院/化學工程學系所/碩士(2010年)

摘要

酒精濃度感測器在各領域中，不論是做液相或氣相感測，皆須具備高靈敏度高選擇性以及短的應答時間，目前已經有很多感測酒精濃度的方法和策略被發表出來。用感測器感測酒精是最便宜和最簡單的方法之一。
使用半導體（電阻式）與電化學方法（電流式）做為酒精感測器已經廣泛的被討論。根據文獻指出半導體感測器通常需要在高溫下操作。在電化學酒精感測器中分成兩種型態，一種為觸媒修飾電極另一種為金屬或是金屬氧化物修飾電極，觸媒修飾電極有不穩定且具有氧氣存在等問題。此研究使用金屬與金屬氧化物電極進行研究，其組成有固態高分子電解質鎳電極以及酒精氣體來進行酒精氣體感測。
本研究製備之氣相酒精感測器，結果顯示其濃度與應答電流呈線性關係，感測系統包含，鎳工作電極、改良式銀/氯化銀參考電極、碳對電極、以及含有氯化鉀水溶液0.4N之固態高分子電解質，以基材為網印碳電極電鍍鎳，其線性迴歸線方程式為 ，其中y為應答電流、x為感測氣體濃度，應答時間100秒，靈敏度為
4.9×10-3μA．L/cm2．mg，基材為碳紙電鍍鎳，其線性迴歸線方程式為 ，其中y為應答電流、x為感測氣體濃度，應答時間800秒，靈敏度為2.446×10-4μA．L/cm2．mg，以上可偵測酒精氣體濃度最低可達0.2mg/L，無電鍍方面，其線性方程式為 ，其中y為應答電流、x為感測氣體濃度，應答時間300秒，靈敏度為1.684×10-3μA．L/cm2．mg，其最低感測濃度為0.25mg/L。選擇率方面，使用丙酮作為干擾氣體，其線性方程式為 ，其中y為應答電流、x為感測氣體濃度，應答時間100秒，靈敏度為6.633×10-5μA．L/cm2．mg在相同濃度中丙酮的感測訊號約為酒精的三十分之ㄧ，因此可以確定電極具有良好的選擇性。在連續測試中，應答電流會隨酒精氣體濃度上升，重複性測試中，酒精濃度0.3mg/L，在七次測試裡其應答電流減弱約0.193%。最後利用高分子膜的厚度證實，應答電流會受到質傳阻力的影響。

關鍵字

酒精 ； 固態高分子電解質 ； 溶膠-凝膠法 ； 感測器

並列摘要

To sense ethanol concentrations in both gas and liquid phases with high sensitivity, selectivity and short response time are necessary in many areas. Many methods and strategies had been reported for the measurement of ethanol concentration. Sensing ethanol by sensors is the cheapest and simplest one.
Semiconductor（resistance type） and electrochemical（current type） methods for ethanol sensors were widely explored. The semiconductor sensors disadvantages of usually operating at higher temperature and poor selectivity was reported. The enzyme modified electrode and metal or metal oxide electrode are two types of electrochemical ethanol sensors. Enzyme modified electrodes have the instability problem and needs the presence of oxygen. Metal and metal oxide electrodes have been investigated. The combination of solid polymer electrolyte with nickel electrode for alcohol gas sensing is carried out in this study.
The result indicate that a linear relationship between alcohol gas concentration and response current by using the same ethanol gas sensors. In the sensing system included nickel working electrode, modified Ag/AgCl reference electrode, carbon material counter electrode and solid polymer electrolyte PVA with ionic liquid KOH 0.4N.The electroplating nickel on carbon electrode as working electrode.At applied potential 0.0004V (vs. modified Ag/AgCl), the sensitivity of sensing system was 4.9×10-3μA．L/cm2．mg, the response time is 100 sec, and the ethanol concentration responsing current is linear, , when y is current, A, x is ethanol gas concentration, mg/L.And electroplating nickel on carbon material paper electrode as working electrode At applied potential 0.0004V (vs. modified Ag/AgCl), the sensitivity of sensing system was 2.446×10-4μA．L/cm2．mg, the response time 800 sec, and the ethanol concentration responsing current is linear, , when y is current, A, x is ethanol gas concentration, mg/L.The detection limit attained to 0.2mg/L.
And electrolessplant nickel working electrode, the sensitivity of sensing system was 1.684×10-3μA．L/cm2．mg, the response time 300 sec,and the ethanol concentration responsing current is linear, , when y is current, A, x is ethanol gas concentration, mg/L.The detection limit attained to 0.25mg/L
In Selectivity test, the acetone concentration responsing current is linear, , when y is current, A, x is acetone gas concentration, mg/L, the sensitivity of sensing system was 6.633×10-5μA．L/cm2．mg, the response time 100 sec
In this study, the response current of alcohol gas sensing is thirty times of the response current of acetone gas sensing, the electrode has good selectivity. In the continuous test, the response current is proportional to the ethanol gas concentration. The repeat test, there are six tests with decreasing 0.193% responst currents for ethanol concentration 0.3mg/L sensor. The solid polymer film thickness significantly affect the response current confirmed that the current respons is a mass transfer control.

並列關鍵字

sensors ； sol - gel method ； solid polymer electrolyte ； alcohol

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