Studies on PBI‐Based Amperometric Sensor for Hydrogen Sensing for Application in Sodium Cooled Fast Reactor

ABSTRACT Hydrogen sensors play a crucial role in monitoring safety in the processes where hydrogen is released or handled in large quantities in fields like chemical and sodium cooled nuclear reactors. An electrochemical sensor in amperometric mode was developed and studied using proton conducting polymer electrolyte membrane of phosphoric acid (PA) doped polybenzimidazole (PBI) PA‐PBI. The PA‐PBI was characterized using Fourier transform infrared spectroscopy (FTIR) to confirm PA doping. The electrolyte was sandwiched between platinum catalyst coated carbon paper gas diffusion electrodes and hot pressed to make an electrochemical cell. The assembled cell was investigated using an electrochemical impedance spectroscopy over a temperature range of 303–453 K to determine temperature dependent proton conductivity. Activation energy for proton conductivity of the electrolyte was determined to be 24.9 ± 2.7 kJ mol −1 . The cell was tested for hydrogen sensing behavior in the hydrogen concentration range of 0.00%–4.00% by keeping the sensor at the optimum temperature of 423 K. The sensor had good sensitivity of about 6.41 mA/% of H 2 in argon with a good repeatability. The sensor was also tested for its effects on relative humidity on hydrogen sensing, interference of the other reducing and oxidizing gases.