Constructing CO-immune water dissociation sites around Pt to achieve stable operation in high CO concentration environment.

The serious problem of carbon monoxide (CO) poisoning on the surface of Pt-based catalysts has long constrained the commercialization of proton exchange membrane fuel cells (PEMFCs). Regeneration of Pt sites by maintaining CO scavenging ability through precise construction of the surface and interface structure of the catalyst is the key to obtaining high-performance CO-resistant catalysts. Here, we used molybdenum carbide (MoC x ) as the support for Pt and introduced Ru single atoms (SA-Ru) at the Pt-MoC x interface to jointly decrease the CO adsorption strength on Pt. More importantly, the MoC x and SA-Ru are immune to CO poisoning, which continuously assists in the oxidation of adsorbed CO by generating oxygen species from water dissociation. These two effects combine to confer this anode catalyst (SA-Ru@Pt/MoC x ) remarkable CO tolerance and the ability to operate stably in fuel cell with high CO concentration (power output 85.5 mW cm -2 @20,000 ppm CO + H 2 - O 2 ), making it possible to directly use the cheap reformed hydrogen as the fuel for PEMFCs.