ZnO incorporated hybrid catalytic proton exchange membrane for H2 generation

Abstract

Electrocatalytic proton exchange membranes (PEMs) represent a promising avenue for advancing the field of electrochemical energy conversion and storage by combining the proton-conducting function of PEMs with enhanced catalytic activity by incorporation of metal ions. Here, we systematically studied the ZnO-based metal-organic framework (MOF) and found the introduction of pegylated ZnO to the (diethyl methylamine)/(H2PO4) matrix to form the p-type conducting MOF membrane with a bandgap of 3.67 eV. This membrane not only has a high protonic conductivity of 0.027 S/cm at 300 K with a transference number >0.99 but also possesses high activity (Tafel slope ∼36 mV/decade). The high reaction kinetics supported by finite element modeling simulations shows its ability to produce efficient and sustainable hydrogen. Our results suggest high current density of 1.52 mA/cm2, a turn over frequency [H2 (s−1)] ∼0.474×1018s−1, and a stability of 168 h in neutral medium (pH = 7). This work will enhance new strategies for fabricating membranes with ionic liquid in order to get membranes with protonic conductivity along with high activity for large-scale water electrolysis.