High Performance Monometallic Platinum Fuel Cell Catalyst Derived from Self-Hole-Confined Nanoparticles and Nitrogen-Anchored Single-Atoms.

Platinum and non-precious metal (PtM) alloy multimetallic catalysts have been developed to address the kinetically sluggish oxygen reduction reaction (ORR) occurring at the cathodes of proton exchange membrane fuel cells (PEMFCs). However, these catalysts inevitably suffer from poor lot-to-lot consistency of chemical compositions and structures during production, and the transition metal leaching in practical applications. Thus, the development of high-performance monometallic Pt catalysts using innovative nanoarchitectures has become important to address the technical challenges that hinder the widespread deployment of the PEMFCs. Here, a monometallic Pt catalyst is developed, which composes of self-hole-confined Pt nanoparticles and nitrogen-anchored Pt single-atoms. The monometallic Pt catalyst exhibits high ORR activity and durability, which is comparable to that of state-of-the-art multimetallic PtM alloy catalysts. A membrane electrode assembly utilizing the monometallic Pt catalyst as a cathode demonstrated a mass activity of 0.87 A mg_Pt ^-1 @ 0.9 V_iR-free. After undergoing 30000 square-wave cycles, the assembly exhibited a 23% decline in mass activity and a potential drop of 16 mV at 0.8 A cm^-2. The results of this study would lead to a critical breakthrough in the performance of monometallic Pt catalysts utilized in PEMFCs.