Catalyst ink composition and catalyst coated membranes for electrolysis

A catalyst coated membrane comprising:

• a membrane;
• a layer of catalyst on a first surface of the membrane, wherein the catalyst layer comprises:
• a catalyst;
• an ionomer;
• and
• optionally an additive;
• wherein the catalyst layer is formed from a catalyst ink comprising:
• a catalyst;
• an ionomer;
• a solvent;
• a porogen soluble in the solvent;
• and
• optionally an additive.

A method of making a catalyst coated membrane comprising:

• coating a layer of catalyst ink on a first surface of a membrane to form a coated membrane, the catalyst ink comprising:
• a catalyst;
• an ionomer;
• a porogen;
• a solvent;
• and
• optionally an additive;
• drying the layer of catalyst ink to form a catalyst layer on the first surface of the membrane;
• and
• removing the porogen from the catalyst layer to create pores in the catalyst layer.