Modified ion-conducting membranes (10), and a method for making the same, which increases the membrane (10) surface area, and, optionally, incorporates mono- and multi-metal ion-containing catalysts for both fuel consumption catalysis in fuel cells as well as catalysis of reactions to ameliorate the effects of CO and other impurities in fuel cells. The membranes (10) modified by these methods can fin application in catalysis and transport applications.