Hydrogen sensing based on proton and electron transport across and along the interface solid oxide electrolyte-platinum electrode

new class of low temperature proton-conducting-type hydrogen gas sensor was developed using Dion -Jacobson type layered perovskite oxides. A laminated structure with a junction of charge carriers at the interface between a predominantly ionically and predominately electronically conducting material was prepared by using the multistep-impregnation-reduction method for the deposition of Pt on top of a perovskite oxide. The proton conductivity of the layered perovskite materials was studied between room temperature and 250 degrees C. The sensing characteristic was studied by using H-2 concentrations between 1% and 7%. The optimum operating temperature of the sensor was found to be at 45 degrees C. The formation of the galvanic cell voltage is described in terms of reactions at the interfaces and the surface of the electrodes. The experimental results indicate the motion of electrons within the Pt and of protons within the perovskite oxide along the interface. Hence, modelling the system response upon a change in gas concentrations can be beneficial for understanding the individual processes and optimizing the overall performance.