Design And Performance Study Of Hydrogen Sensor Based On PEMFC With New Sealing Structure

Facing severely environmental pollution and crisis of fossil energy reserves,the use of renewable clean energy-hydrogen is becoming a trend.As some special properties of hydrogen:colorless,odorless but flammable and explosive,it’s critical to measure hydrogen leakage timely to ensure the safety for use.In many types of hydrogen sensor,electrochemical hydrogen sensor especially PEMFC hydrogen sensor receives widely attention and research due to its unique advantages.The traditional structure of PEMFC hydrogen sensor as the existence of encapsulation mode and dimensional accuracy problem that may cause gas leakage,makes the accuracy of the sensor is affected and can’t guarantee the stability.From the encapsulated structure of sensor as a start,this paper develop a novel sealing structure of hydrogen sensor and investigate the performance.On the one hand,gas diffusion layer with different carbon loading were prepared.The effect of gas diffusion layer electrode with different carbon loading on the sensor performances:sensitivity and electrochemical kinetics and ECSA were investigated.Results indicated that the sensor showed the best performance with carbon loading of 0.357 mg.cm^-2 in GDL.The sensitivity of sensor was0.0445μA cm^-2 ppm^-1 in hydrogen concentration range of 1.6%to 40%;the response current of sensor reached 34 mA cm^-22 in hydrogen concentration range of 40%to 99%;the response time of sensor was 8-50s.Besides,gas diffusion electrode with carbon loading of 0.357 mg.cm^-2 also showed the best electrochemical performance.On the other hand,the formula of catalyst layer with different Pt and Nafion content were prepared by the orthogonal method.The effect of catalyst layer with different formula on the sensor performances:sensitivity and electrochemical kinetics and ECSA were investigated,and analyze the primary and secondary relationship for each content.At last,get the optimal formula corresponding to each hydrogen concentration range.The research showed that the sensor optimal sensitivity was 0.0502μA cm^-2 ppm^-1 in the hydrogen concentration range of 1.6%to 40%;the Nafion content of cathodic catalyst layer had the greatest influence on sensor’s sensitivity,Pt content of cathodic catalyst layer second,Nafion content of anodic catalyst layer had minimal impact;the best formula was a₄b₂c₃d₃;In hydrogen concentration range of 40%to 99%,the sensor optimal sensitivity was 0.0568μA cm^-2 ppm^-1 and the maximum response current reached 52.4mA cm^-2,the best formula a₂b₄c₃d₂.By analyzing the EIS and ECSA of each sensor with different formula,the result showed formula a₂b₄c₃d₂ exerted the best electrochemical characteristics,formula a₄b₂c₃d₃ represented the highest catalyst activity.The response time of sensor was 7-50s.