The Use of a Protein Scaffold to Control the Structure of Electrodes and Ionomer in Proton Exchange Membrane Electrolyzers

Abstract

Among the frontrunners of hydrogen production technology, proton exchange membrane (PEM) electrolysis is safe, simple, and highly efficient. PEM electrolysis has ability to be integrated in a variety of energy systems and infrastructures such as transportation, renewable electricity, biogas upgrading, as well as ability to address seasonal-variation in long timescales. One of the major challenges that remains is the high cost of noble-metal catalysts in the membrane electrode assembly (MEA). Recent attempts in research and development are directed toward low-loading of platinum group metals. We engineered a synthetic protein to improve platinum catalyst utilization in the MEA, and control ionomer-catalyst interfaces. The multifunctional protein is engineered to direct ionomer (the electrolyte) towards platinum active sites. With the protein added to catalyst layer, the nanostructure and phase separation were examined and compared with a conventional catalyst layer. The engineered protein additive results in distinct structural changes in the electrode. This work yields a promising model for controlling ionomer catalyst interactions, and could lead low platinum group metal PEM electrolyzers.