Durability of a recombination catalyst-based membrane-electrode assembly for electrolysis operation at high current density

Hydrogen production through polymer electrolyte membrane water electrolysis was investigated at high current density (4 A cm). A PtCo recombination catalyst-based membrane-electrode assembly (MEA) was assessed in terms of performance, efficiency and durability. The electrolysis cell consisted of a thin (50 µm) perfluorosulfonic acid membrane and low platinum group metals (PGM) catalyst loadings (0.6 mg PGM cm). An unsupported PtCo catalyst was successfully integrated in the anode. A composite catalytic layer made of IrRuOx and PtCo assisted both oxygen evolution and oxidation of hydrogen permeated through the membrane. The cell voltage for the recombination catalyst-based MEA was about 30 mV lower than the bare MEA during a 3500 h durability test. The modified MEA showed low performance losses during 3500 h operation at high current density (4 A cm) with low catalyst loadings. A decay rate of 9 µV/h was observed in the last 1000 h. These results are promising for decreasing the capital costs of polymer electrolyte membrane electrolysers. Moreover, the stable voltage efficiency of about 80% vs. the high heating value (HHV) of hydrogen at 4 A cm, here achieved, appears very promising to decrease operating expenditures.