Ni@PdCu Core–Shell Catalyst for Direct H2O2 Synthesis: Strain–Ligand Synergy Revealed by Experiment and DFT

Abstract

Direct synthesis of hydrogen peroxide (DSHP) from H2 and O2 over Pd-based catalysts offers a green alternative to the anthraquinone process, yet its practical application is hindered by the inherent activity-selectivity trade-off of Pd. Herein, we report a Ni@PdCu core–shell catalyst supported on N-doped porous carbon (Ni@PdCu/NPCs) synthesized via a two-step ethylene glycol-assisted reduction strategy, which achieves an exceptional H2O2 selectivity of 95.3%. Systematic characterization by TEM, XRD, XPS, and ICP-OES confirms the successful construction of the Ni@PdCu core–shell architecture with a uniform PdCu alloy shell. Density functional theory (DFT) calculations demonstrate that the strain effect, combined with the geometric isolation of Pd sites by Cu alloying, synergistically increases the O2* dissociation barrier from 0.56 to 0.84 eV while decreasing the hydrogenation barrier from 0.88 to 0.60 eV, thereby redirecting the reaction pathway from O–O bond cleavage toward H2O2 formation. This work establishes a synergistic strain-ligand engineering strategy for designing high-performance Pd-based catalysts for DSHP.