Abstract: The invention is directed to highly porous catalyst coated membranes and to sprayable inks and processes for forming catalyst coated membranes. In one aspect, the invention is to a sprayable ink, comprising catalyst particles, polymer electolyte ionomer, and a vehicle for dispersing the catalyst particles and polymer electolyte ionomer. In another aspect, the process comprises the steps of depositing an ink comprising catalyst particles and a vehicle onto a membrane and vaporizing from 40 to 95 weight percent of the vehicle from the sprayed ink under conditions effective to form a catalyst layer on the membrane. Preferably, the depositing and vaporizing steps are alternated to form multiple stacked catalyst layers on the membrane.