Potentiometric pH Sensor Based on MoO3 Film Modified With WO3 Nanoparticles

This study presents a pH sensor based on molybdenum trioxide (MoO3) film modified with tungsten trioxide (WO3) nanoparticles. MoO3 film was prepared by R. F. sputtering, and hydrothermally synthesized WO3 nanoparticles were drop-cast on the MoO3 film for hydrogen ion detection. The sensing mechanism was based on voltage measurement. The structure and morphology of the prepared materials were analyzed using X-ray diffraction and scanning electron microscopy, and the successful synthesis of the materials was confirmed by X-ray photoelectron spectroscopy. Linear range of the WO3 nanoparticles/MoO3 potential sensor expanded from a pH range from 1–5 to 1–7, with a sensitivity of 32.49 mV/pH. The sensor also demonstrated fast response, good repeatability, and strong resistance to interference, achieving an excellent recovery rate in measurements of commercial fruit juices. This study offers a new approach for acid sensing.