Membrane-electrode junction properties for optimum potentiometric hydrogen sensor response

Technology for monitoring the concentration of high-concentration hydrogen gas, which is used as a fuel for hydrogen fuel cell vehicles, is urgently needed to be developed to maximize vehicle fuel efficiency. To improve the detection performance of the proton conductor-based hydrogen sensor, a membrane electrode assembly (MEA) consisting of a Nafion membrane and a Pt-C composite electrode was manufactured and applied to the hydrogen sensor. The hot press method was used to manufacture the MEA, and the junction characteristics were optimized by changing pressure, temperature, and time. The MEA was manufactured at a pressure range of 2–5 MPa, a temperature range of 40–80 °C, and a time range of 60–120 s, and the sheet resistance of the MEA was measured to investigate its dependence on the bonding process conditions. When the electrode-Nafion junction temperature and pressure were high, the MEA was stuck to the substrate or paper sheet and could not be separated into a discrete MEA. Additionally, when the temperature was low, the junction strength was insufficient, causing the Nafion and electrode to separate from each other. Through this study, it was confirmed that a robust and conductive MEA was obtained under optimal bonding conditions of 2 MPa, 60 °C, and 60 s, and the sensitivity of the hydrogen sensor was significantly improved.