Proton exchange membrane fuel cells powered with both CO and H<sub>2</sub>.

Wang, Xian; Li, Yang; Wang, Ying; Zhang, Hao; Jin, Zhao; Yang, Xiaolong; Shi, Zhaoping; Liang, Liang et al. · Proc Natl Acad Sci U S A · 2021

basic_science · Level V

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Abstract

The CO electrooxidation is long considered invincible in the proton exchange membrane fuel cell (PEMFC), where even a trace level of CO in H<sub>2</sub> 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, H<sub>2</sub>, or a combination of the two. With a small amount of metal (24 μg<sub>metal</sub>⋅cm<sup>-2</sup>) used in the anode, the H<sub>2</sub> fuel cell performs its peak power density at 1.43 W⋅cm<sup>-2</sup> When operating with pure CO, this catalyst exhibits its maximum current density at 800 mA⋅cm<sup>-2</sup>, 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 H<sub>2</sub>O and to further facilitate CO activation. These findings open up an avenue to conquer the formidable poisoning issue of PEMFCs.