A new potentiometric SO2 sensor based on Li3PO4 electrolyte film and its response characteristics

Abstract

A potentiometric SO2 gas sensor based on Li3PO4 solid electrolyte has been developed using Au as the reference electrode and Li2SO4/V2O5 as the sensing electrode. The Li3PO4 film was deposited on Al2O3 substrate by resistance heating evaporation. Two Au films with designed patterns were formed on the Li3PO4 film by micro-fabrication technologies. The sensing electrode covers one electrode partly using thick-film technology. The electromotive force values between the sensing electrode and the reference electrode were measured and various characteristics were studied including sensitivity, response characteristics, and stability and selectivity. According to the results, we conclude that an optimal working temperature of the SO2 sensor is 500 °C, the measurement range is 0-100 ppm, the sensitivity is about 32.47 mV/dec, the response and the recovery time is about 5 min and 10 min, respectively. And the stability and the selectivity of the sensor are good, making it have potential in SO2 measurement of living environment.

Rapid Solid‐State Gas Sensing Realized via Fast K+ Transport Kinetics in Earth Abundant Rock‐Silicates

“…The sensor in this study, within the same temperature and SO 2 concentration range, demonstrated a robust and stable output signal (as high as 220 mV for 2 ppm of SO 2 ), similar or superior sensitivity (by a factor of 10) as well as faster response/recovery time (as low as 1 min) compared to type III PGS based on Li/Na-ISICs and similar sulfate SE. [1,3] The response/recovery time in this study is among the fastest reported in the literature [1,3,4,12,[48][49][50][51][52][53][54][55][56][57][58][59] for the PGS with oxide electrolytes (Figure 3d). A comparison between the sensor performance in this study and reported values with some of the reported type III PGS in literature is demonstrated in Table 1.…”

“…The establishment of the above equilibrium reactions Equation ( 1)-(3) will fix the A þ chemical potential on the SSE surface in SSE/SE as well as SSE/RE interfaces and creates a chemical potential difference between the two electrodes. This chemical potential difference between these two surfaces can be measured as an electrical potential (emf ) caused by overall cell reaction Equation (4) via the Nernst Equation ( 5) the as follows: This study KMS 69-72 mV dec À1 @ 500 °C 1-6 77 mV dec À1 @ 500 °C Balaish et al [1,3] LLZO 8-144 mV dec À1 @ 480 °C 4-60 75 mV dec À1 @ 480 °C Wang et al [54] Li 3 PO 4 32.47 mV dec À1 @ 500 °C 5-10 77 mV dec À1 @ 500 °C Izu et al [52] NASICON 75-85 mV dec À1 @ 600 °C 10 87 mV dec À1 @ 600 °C Min et al [50] NASICON 163 mV dec À1 @ 550 °C 3-5 82 mV dec À1 @ 550 °C…”