Defect engineering boosts CC bond cleavage for highly efficient ethylene glycol electrooxidation on Pd₂Pb₃Zn₄...

Optimizing the surface-interface structure and electronic interactions of palladium-based materials is crucial for accelerating the electro-oxidation of liquid fuels; However, the sluggish kinetics and complicated oxidation process still pose formidable challenges for their application in fuel cells. Herein, we fabricated defect-rich Pd₂Pb₃Zn₄ (D-Pd₂Pb₃Zn₄) intermetallic compound featuring nanonetwork structure. Notably, the introduction of plumbum (Pb) element promotes the generation of an ordered palladium-based alloy, whereas the leaching of zinc (Zn) element is crucial for the creation of defects. This catalyst features a highly open structure, strong electronic effect, and sufficient active sites, demonstrating remarkable electrocatalytic activity and excellent durability for ethylene glycol oxidation reaction (EGOR) in alkaline electrolyte. Impressively, the mass activity of the D-Pd₂Pb₃Zn₄/C electrocatalytic EGOR is as high as 11.9 A mg_Pd^-1, which is 1.2 and 9.0-fold higher than that of the Pd₂Pb₃Zn₄/C (9.86 A mg_Pd^-1) and Pd/C (1.32 A mg_Pd^-1) catalysts, respectively. Kinetic and thermodynamic analyses reveal that the D-Pd₂Pb₃Zn₄/C catalyst is superior to the Pd₂Pb₃Zn₄/C catalyst in terms of facilitating mass transfer, reducing the electrochemical activation energy, enhancing electronic conductivity, accelerating charge transfer, improving the resistance to CO poisoning, and maintaining satisfactory long-term stability. Meanwhile, in-situ fourier transform infrared (FTIR) spectrum confirmed that the D-Pd₂Pb₃Zn₄/C enhances the selectivity toward C1 products from ethylene glycol oxidation as compared to the Pd₂Pb₃Zn₄/C catalyst, with an optimal selectivity of 42.7% that underscores its superior CC bond cleavage ability. This study not only provides an effective synthetic strategy for preparing Pd-based nanomaterials with defective and ordered structures, but also has important guiding significance for optimizing EGOR via the C1 pathway.