Sub-ppb mixed potential H2S gas sensor based on YSZ and Nd2AO4 (A=Cu, Ba and Ni) as a new type of sensing electrode

In this paper, for the detection of hazardous gas hydrogen sulfide (H2S), new type YSZ (yttria stabilized-zirconia)-based mixed potential gas sensor is developed and K2NiF4 type oxides Nd2AO4 (A=Cu, Ba and Ni) are successfully synthesized as sensing electrode (SE). XRD results shows the materials have pure phase K2NiF4-type oxides. Compared with other sensors, the sensor based on Nd2NiO4 sensing electrode has the highest response value to 1 ppm H2S. Polarization curve results show that the reason for the highest response value is that it has the strongest electrochemical catalytic activity to H2S. Moreover, the response of the sensor based on Nd2NiO4-SE to 1 ppm H2S is − 28 mV with fast response/recovery time (70 s/135 s). The low detection range is 0.05 ppm, meeting the requirement of security monitoring field. The sensitivities of the sensor to 0.05–0.2 ppm and 0.2–10 ppm H2S are − 5 mV/decade and − 63 mV/decade respectively. Besides, the present device also performs good repeatability, excellent selectivity and acceptable stability during 30 days continuous measurement, which demonstrated that the sensor we fabricated has a good application prospect for the field of real-time and in-situ security monitoring of hydrogen sulfide.