In this paper, we proposed a microfabricated electrolyte-insulator-semiconductor (EIS) sensor based on CeTixOy sensing membrane for pH detection in biofluid. Structural and morphological behaviors of the sensing films at different fabrication temperatures were investigated by X-ray diffraction, atomic force microscopy, high-resolution transmission electron microscopy, electron energy loss spectroscopy, and Xray photoelectron spectroscopy. The EIS sensor fabricated with the CeTixOy sensing membrane annealed at 800 degrees C exhibited a super-Nernstian pH sensitivity of 89.81 mV/pH (in the range pH similar to 2 to 12) with a smaller hysteresis voltage of 1 mV and a lower drift rate of 0.34 mV/h at standard buffer solution of pH = 7. This result is attributed to the ion exchanges in the surface layer of electrode membrane containing OH- groups and redox transition between two oxidation states of Ce(III) oxide and Ce(IV) oxide. (c) 2018 Elsevier Ltd. All rights reserved.