The relation between mixed-potential hydrogen response and electrochemical activities for perovskite oxides

Development of high-performance mixed potential gas sensors is challenging, due to a lack of understanding towards the key material properties affecting the sensing performance. Herein, with a combined theoreticalexperimental study, we show that mixed potential response of perovskite oxides to hydrogen correlates to ratio of the electroactivities (exchange current densities or polarization resistances) under typical Tafel-type sensing condition. Experimental results obtained for five different perovskites indicate that a greater ratio of activities for the hydrogen oxidation reaction and the oxygen reduction one favors larger response, following a semi-logarithm relation, which agrees well with the theoretical prediction. The activity ratio could serve as a descriptor of response that is potentially applicable to different materials and target gases. These findings link mixed potential gas response to intrinsic materials properties, and would help guide the design of high response materials.

Automated summary

Through theoretical and experimental studies, it has been found that the mixed potential response of perovskite oxides to hydrogen is correlated to the ratio of electroactivities, with a greater ratio leading to a larger response. This ratio can serve as a descriptor of response and potentially guide the design of high-response materials.