Hydrogen-Transfer Bridging at Zeolite-Confined Pd–Ni(OH)2 Interfaces Enables Efficient Direct Synthesis of Hydrogen Peroxide

Abstract The direct synthesis of hydrogen peroxide (H2O2) from H2 and O2 provides a sustainable route for decentralized oxidant production, but its practical use is limited by inefficient Pd utilization, undesired H2O2 decomposition, and the need for high noble-metal loadings. Here, we report a Ni(OH)2-promoted Pd@S-1 catalyst that integrates zeolite confinement with interfacial electronic modulation for efficient aqueous H2O2 synthesis. The optimized Pd4Ni1@S-1-H catalyst delivers an H2O2 productivity of 3.39 mol gPd–1 h–1 under acidic conditions, representing the highest value among reported semibatch glass reactor systems and a 10-fold improvement in Pd utilization efficiency relative to a commercial Pd/C catalyst. Advanced spectroscopic analysis and density functional theory calculations reveal that Ni(OH)2 donates electrons to Pd, lowering the average Pd valence state from 1.83 to 1.39, and serves as a hydrogen-transfer bridge that promotes hydrogen migration to the *O–O intermediate. Meanwhile, hydrophobic silicalite-1 (S-1) zeolite micropores enrich dissolved H2/O2 and suppress secondary H2O2 decomposition by facilitating product desorption. The resulting in situ H2O2 generation system enables efficient Cr(VI) reduction, highlighting its potential for sustainable water remediation.