Hydrogen Production at a Low Voltage of 0.46 V @ 0.4 A/cm2 at 850 °C in SOECs Enhanced by Anode Oxidation of Methane

Introducing methane on the anode side of solid oxide electrolysis cells can consume oxygen species and produce hydrogen at a low voltage. This study employs an incorporation–segregation method to obtain platinum loaded Sm_0.2Ce_0.8O_1.9 catalysts (Pt-SDC) with excellent catalytic activity for methane oxidation. The results show that 4% Pt-SDC achieves a high current density of 0.4 A/cm² at 0.46 V with methane oxidation over the anode, which exhibits a relatively low activation energy of 80.19 kJ/mol for methane oxidation. The electrochemical performance is highly dependent on thermal oxidation activity. Impedance fitting reveals a reduced polarization resistance from 3.27 Ω cm² for Pure SDC to 0.73 Ω cm² for 4% Pt-SDC. The results indicate that methane is oxidized on the anode side. The incorporation of Pt enhances the stability of the electrolysis cell, and the voltage increase rate is 0.2 mV/h for 4% Pt-SDC and 1.8 mV/h for Pure SDC, respectively.