MXene-copper oxide/sulfonated polyether ether ketone as a hybrid composite proton exchange membrane in electrochemical water electrolysis

Abstract

Water electrolysis through a proton exchange membrane is one approach for hydrogen energy production via a simple redox reaction. This work focused on the development of a hybrid composite proton exchange membrane (PEM), MXene-Cu2O/SPEEK, which was used for proton transfer in a water electrolysis process. The sample of the 4%MXene-Cu2O/SPEEK membrane demonstrated the highest proton conductivity of 0.0105 Scm−1 at 30 °C. Further, the oxygen transmission rate of the 4%MXene-Cu2O/SPEEK was 33.67 cc m−2 day−1, whereas that of the commercially available Nafion 212 was 28.53 cc m−2 day−1. The flow rate of H2 gas evolution was 3.68 mL min−1 when using the 4%MXene-Cu2O/SPEEK composite PEM as the H+ ion exchange separator in the water electrolysis system; this flow rate is faster than that of a pristine SPEEK membrane. Interestingly, the addition of the MXene-Cu2O composite into the SPEEK polymer matrix promoted the oxidative stability of the composite PEM, which is vital for the long-term operation of the PEM water electrolysis. The 4%MXene-Cu2O/SPEEK composite membrane produced 0.083 μmol of H2 gas in 1 h, and it slightly reduced to 0.074 μmol after 8 h, which shows a stable H2 production and good efficiency of the membrane.