Open AccessAu thin‐film electrodes based potentiometric CO 2 sensor using Li 3 PO 4 as both the reference material and the solid electrolyte
Author(s) -
Wang Hairong,
Chen Di,
Liu Zhen,
Zhang Mi
Publication year - 2016
Publication title -
micro and nano letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.25
H-Index - 31
ISSN - 1750-0443
DOI - 10.1049/mnl.2016.0240
Subject(s) - potentiometric titration , electrolyte , electrode , materials science , fast ion conductor , potentiometric sensor , thin film , analytical chemistry (journal) , inorganic chemistry , chemistry , nanotechnology , environmental chemistry
Thin‐film Au electrodes prepared by magnetron sputtering method were used to develop a potentiometric CO 2 gas sensor. The thermal evaporated Li 3 PO 4 played the role of electrolyte and sensing material. This design can simplify the fabrication process compared with the conventional solid electrolyte potentiometric CO 2 sensor (c‐sensor) and improve the performance compared with the thick‐film Au electrodes sensor (t‐sensor). The designed CO 2 sensor (d‐sensor) presented good response characteristics at the CO 2 concentration range of 250–2500 ppm and the electromotive force (EMF), ΔEMF/dec, response and recovery time were investigated. The EMF values of the sensor were linearly dependent on logarithm of CO 2 partial pressure at the working temperatures between 420°C and 500°C. The d‐sensor showed a sensitivity of 79.1–93.7 mV/dec at working temperatures range of 420–500°C which was much higher than the sensitivities of c‐sensor and the t‐sensor. The response and recovery time of the fabricated sensors were 10 and 14 s at working temperature of 500°C, respectively. The surface morphology of Au thin films was considered to increase the three‐phase interface area and be good for the reaction gases to diffuse from Au film to lithium phosphate, allowing rapid chemical reaction equilibrium, getting a more stable EMF output.