Proton exchange membrane fuel cells powered with both CO and H2

The CO electrooxidation is long considered invincible in the proton exchange membrane fuel cell (PEMFC), where even a trace level of CO in H2 seriously poisons the anode catalysts and leads to huge performance decay. Here, we describe a class of atomically dispersed IrRu-N-C anode catalysts capable of oxidizing CO, H2, or a combination of the two. With a small amount of metal (24 μgmetal⋅cm−2) used in the anode, the H2 fuel cell performs its peak power density at 1.43 W⋅cm−2. When operating with pure CO, this catalyst exhibits its maximum current density at 800 mA⋅cm−2, while the Pt/C-based cell ceases to work. We attribute this exceptional catalytic behavior to the interplay between Ir and Ru single-atom centers, where the two sites act in synergy to favorably decompose H2O and to further facilitate CO activation. These findings open up an avenue to conquer the formidable poisoning issue of PEMFCs.