Pd–Cu Core–Shell Nanoclusters for Ethylene Glycol Electrooxidation: A Theoretical Investigation

The electrocatalytic oxidation of ethylene glycol (EG) is crucial for energy conversion and value-added chemical synthesis, yet comprehensive theoretical studies mapping its full reaction landscape are still lacking. This work employs first-principles calculations to systematically investigate Pd-Cu core-shell nanoclusters (13- and 55-atom models) for EG oxidation, revealing how cluster size, atomic arrangement, and electronic properties collectively influence both reaction pathway selectivity and thermodynamic stability. We demonstrate that cluster stability depends critically on metal distribution, with a Cu-core/Pd-shell configuration being most favorable. In the reaction pathway, Cu-rich surfaces tend to preserve the C-C bond, while Pd-rich surfaces promote C-C cleavage. Further, Cu doping slightly upshifts Pd's d-band center, optimizing CO adsorption to enhance antipoisoning capability without compromising activity. Notably, the optimal Cu₁@Pd₁₂ catalyst reduces the Gibbs free energy change of the rate-determining step (ΔGRDS) for formic acid production to 0.1227 eV, far lower than that of the monometallic Pd₁₃ cluster. These electronic and structural effects collectively enable a favorable balance between activity, selectivity, and stability. The study establishes an elegant strategy for designing tunable, poisoning-resistant nanocluster electrocatalysts and offers a generalizable paradigm for atomic-level catalyst engineering, with promising implications for fuel cells and sustainable electrosynthesis.