Precisely Engineered Nitrogen Dopants in Pd/NC Catalysts: Synergistic Pyridinic-Pyrrolic-Graphitic Triad for Alkaline Methanol Electrooxidation

Despite nitrogen-doped carbons (NC) enhancing metal-support interactions (MSI) in electrocatalysts, how specific N-configurations (pyridinic, pyrrolic, and graphitic) synergistically govern methanol oxidation reaction (MOR) pathways over Pd surfaces remains unknown. Herein, we hypothesize that precise thermal programming of ZIF-8 pyrolysis can tailor synergistic pyridinic-pyrrolic-graphitic N-triads to simultaneously enhance activity, CO tolerance, and stability. Guided by DFT predictions, Pd/NC-<i>T</i> catalysts (<i>T</i> = 700-1100) were synthesized, where in situ pyrolysis controls N-configurations (validated by XPS) and wet impregnation immobilizes ultrafine Pd nanoparticles (3.6 ± 0.8 nm). Furthermore, experimental and theoretical analyses reveal that pyrrolic-N facilitates the adsorption of methanol on Pd, while pyridinic-N suppresses the CHO* → CO* reaction pathway, thus enhancing the catalyst's tolerance to poisoning, and graphitic-N prevents support dissolution and collapse during the electrocatalytic reaction, thus mitigating active site loss. Notably, Pd/NC-900 achieves 4195.0 mA·mg^-1_Pd in the alkaline electrolyte, maintaining 80.5% of its initial current density after 500 cycles at 200 mV/s, highlighting its exceptional catalytic activity and long-term stability. This work offers profound insights into the intricate MSI, serving as a crucial framework for guiding the future design and advancement of MOR electrocatalysts.