Acta Phys. -Chim. Sin. ›› 2017, Vol. 33 ›› Issue (3): 573-581.doi: 10.3866/PKU.WHXB201612122

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Operating Mechanism of Palladium Oxide as a Potentiometric Sensing Electrode

Yan-Gong ZHENG1,*(),Li-Na ZHU1,Han-Yu LI1,Jia-Wen JIAN1,*(),Hai-Ying DU2   

  1. 1 Faculty of Electrical Engineering and Computer Science, Ningbo University, Ningbo 315000, Zhejiang Province, P. R. China
    2 College of Mechanical and Electronic Engineering, Dalian Minzu University, Dalian 116600, Liaoning Province, P. R. China
  • Received:2016-10-24 Published:2017-03-07
  • Contact: Yan-Gong ZHENG,Jia-Wen JIAN;
  • Supported by:
    The project was supported by the National Natural Science Foundation of China(61471210);The project was supported by the National Natural Science Foundation of China(61501271);The project was supported by the National Natural Science Foundation of China(51472126);Natural Science Foundation ofNingbo Municipality, China(2015A610108);K. C. Wong Magna Fund in Ningbo University, China


This paper describes the sensing properties of a potentiometric sensor based on a palladium oxide (PdO) electrode. Our investigation of the sensing mechanism is also discussed. We studied carbon monoxide (CO) sensing performance of a PdO electrode doped with Mg, Ni, and La, printed on zirconia. The results indicated that defects on the surface of PdO, which allow adsorption of CO, can effectively enhance the sensitivity of the sensors. To explore the source of the signal, a PdO-based electrode was printed on an alumina disc and a zeolite pellet for CO detection at 450℃. Notably the zeolite coupled with the PdO-based electrode to generate potentiometric responses to changes in CO concentration. According to the resistance and impedance measurements, the response to CO was ascribed to the changing interfacial potential between the PdO electrode and electrolyte. A model based on an electrochemical double layer between the PdO and electrolyte was determined to explain the behavior of the potentiometric sensor. It may be possible to harness these effects at PdO electrodes for the development of electrochemical sensors.

Key words: Palladium oxide, Potentiometric sensor, Doping effect, Carbon monoxide, Electrolyte


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