Fuel cells hold promise as alternativepower sources due to their ability to bypass Carnot efficiency limitations by directlyconverting chemical energy into electrical energy. However, the high costs of Ptcatalysts and membranes, as well as component durability issues, have barredwidespread implementation. A key area for cost reduction is thedevelopment of novel cathode catalysts, which can greatly reduce fuel cellcosts. In addition to these cost advantages, non-Pt catalysts are oftenmore tolerant to contaminants such as methanol at the cathode. Copper-basedORR catalysts have shown promise in alkaline media, but a high-performance catalysthas not yet been successfully demonstrated in acidic media. Previously, we developed a pH-flexibleflowing electrolyte microfluidic fuel cell, which uses an external referenceelectrode to individually analyze cathode and anode performance. Thismicrofluidic configuration combines the versatility of a traditional threeelectrode cell with the conditions found in an operating fuel cell, allowingfor in-situ studies of catalyst and electrode performance. Externalcontrol over the flowing electrolyte stream allows for controlled introductionof contaminants and maintains their concentrations over the course ofexperimentation. Here, we present our work on thedevelopment and testing of a novel Cu-based ORR catalyst operating in an acidicfuel cell. The effects of varied loading and catalyst forms are demonstrated.The catalyst performance in the presence of contaminants such as methanol andethanol is quantified. Development of this catalyst has the potential toreduce the cost of acidic fuel cell systems and improve the understanding ofCu-based ORR catalysis.