High performance sol–gel synthesized Ce(0.9)Sr(0.1)(Zr(0.53)Ti(0.47))O(4) sensing membrane for a solid-state pH sensor

In this paper, we developed a high-performance solid-state pH sensor using a Ce(0.9)Sr(0.1)(Zr(0.53)Ti(0.47))O(4) (CSZT) membrane through a very simple sol–gel spin-coating process. The structural properties of the CSZT membrane are correlated with its sensing characteristics. The CSZT based EIS sensor exhibited a high pH sensitivity of 92.48 mV pH(−1), which is beyond the Nernst limit (59.4 mV pH(−1)), and good reliability in terms of a low hysteresis voltage of 1 mV and a small drift rate of 0.15 mV h(−1). This behaviour is attributed to the incorporation of Sr in the CSZT sensing membrane, which promotes change in the Ce oxidation state from Ce(4+) to Ce(3+).