Inhibiting Dissolution of Platinum with Atomic Rare Earth Bridged by Nitrogen to Boost Alkaline Hydrogen Evolution

The unfavorable water dissociation and continuous dissolution of Pt single-atom catalysts significantly impede their practical application in alkaline anion exchange membrane water electrolyzers (AEMWEs). Herein, by integrating the electron-buffer functionality of rare earth single atoms (RE = Pr, Ce, Gd, Sm) dispersed on N-doped carbon substrates (N─C) with Pt single atoms, a novel catalyst Pt/RE-N-C is reported. The constructed Pt─N─Ce bridge causes electron enrichment on Pt sites and deficiency on RE sites, which favors adsorption of H_ads and OH_ads, respectively, and significantly promotes water dissociation. Meanwhile, the increased covalency of Pt─N bond inhibits detachment and thermal vibration of Pt atoms. As a representative, Pt/Ce─N─C requires an overpotential of only 22 mV to reach a current density of 10 mA cm^-2. The excellent mass activity of 7.16 A mg_Pt ^-1 at an overpotential of 50 mV is 37.7 times higher than that of commercial Pt/C (0.19 A mg_Pt ^-1). More importantly, the AEMWE with Pt/Ce─N─C (with a loading of only 32 µg_Pt cm^-2) as the cathode catalyst exhibits an ultralow potential (1.79 V) and high stability at an industrial current density of 1.0 A cm^-2. This work demonstrates the advantages and potential of using RE single atoms for high-efficient energy conversion.