Interstitial C/N Doping Stabilizes Pd@Pt Core-Shell Electrocatalysts by Atomic-Scale Interfacial Anchoring and Metal Dissolution Suppression.

Platinum (Pt)-based multimetallic catalysts, including alloys and core-shell architectures, have attracted widespread attention due to their ability to optimize catalytic activity and minimize the use of precious metals. However, their structural instability under harsh electrochemical conditions, such as acidic media and high potentials, hinders commercialization. Here, using well-defined Pd@Pt core-shell nanocrystals as a model system and combining online dissolution analysis (SFC-ICP-MS), identical-location STEM, operando x-ray absorption spectroscopy, and DFT calculations, we identified a pinhole-mediated dissolution mechanism. Specifically, Pd dissolution at pinhole defects disrupts the local interfacial structure, subsequently destabilizing neighboring Pt and leading to irreversible reconstruction of the core-shell architecture, ultimately resulting in shell collapse. We further demonstrated that interstitial C/N doping at the Pd-Pt interface near pinholes could induce atomic-scale interfacial anchoring through strong p-d hybridization, thereby significantly increasing the kinetic barrier for metal leaching. Consequently, compared to the undoped sample, the C/N-doped core-shell catalyst maintained structural integrity at potentials up to 1.50 V (vs RHE), and the dissolution of Pt and Pd was reduced by 48.5 and 13.9 times, respectively. This defect-targeted strengthening strategy, applicable to Pd-Au and Pd-Ag systems, establishes a general principle for stabilizing multimetallic heterointerfaces and developing durable, low-Pt electrocatalysts.