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 μg_metal⋅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.