O-Bridged Co-Cu Dual-Atom Catalyst Synergistically Triggers Interfacial Proton-Coupled Electron Transfer: A New Approach to Sustainable Decontamination

Abstract

Heteroatom-bridged dual-atom catalysts (DACs), featuring more flexible active sites and intermetallic interaction, provide an opportunity for sustainable environmental remediation. Herein, an innovative oxygen-bridged Co-Cu DAC supported on nano-alumina (CoOCu-DAC) is fabricated using a straightforward two-step process. The as-prepared catalyst significantly enhances both decontamination kinetics and peroxymonosulfate (PMS) utilization efficiency by 1–3 orders of magnitude toward monoethanolamine (MEA, pK_a = 9.5) compared to Co single-atom catalyst (Co-SAC) and bulk metal catalysts, and largely outperforms previously reported systems. In-situ ATR-FTIR and theoretical investigations reveal that the secondary introduction of Cu plays multiple important roles: it activates lattice oxygen to trigger key proton transfer (PT) of MEAH⁺ via nucleophilic attack at the interface and subsequently favors deprotonated MEA as an efficient electron donor to accelerate electron transfer (ET) by enhancing orbital overlaps for the co-activation of O₂ and PMS. Such a stepwise proton-coupled electron transfer (PCET)-enhanced catalytic pathway mediated by CoOCu-DAC is fundamentally different from common route identified in Co-SAC-involved Fenton-like system. The established binary QSAR further substantiates the universality of PCET-enhanced strategy toward versatile nitrogen-containing organic compounds. This study offers a new perspective for sustainable water decontamination and other related areas of catalysis based on rationalized design of multifunctional catalysts at atomic level.