Influence of thickness of sub-micron Cu2O-doped RuO2 electrode on sensing performance of planar electrochemical pH sensors

► Changes in thickness of 20 mol % Cu2O-doped RuO2 sensing electrodes affect the sensing performance of the solid-state ceramic pH sensor. ► Thicker electrode shows faster response time to pH changes. ► SEM confirmed the development of “inner” active surfaces within sensing electrode. ► Thicker electrodes developed more advanced crystallization.