Catalytic Membrane with Copper Single-Atom Catalysts for Effective Hydrogen Peroxide Activation and Pollutant Destruction

The superior catalytic property of single-atom catalysts (SACs) renders them highly desirable in the energy and environmental fields. However, using SACs for water decontamination is hindered by their limited spatial distribution and density on engineered surfaces and low stability in complex aqueous environments. Herein, we present copper SACs (Cu₁) anchored on a thiol-doped reactive membrane for water purification. We demonstrate that the fabricated Cu₁ features a Cu-S₂ coordination─one copper atom is bridged by two thiolate sulfur atoms, resulting in high-density Cu-SACs on the membrane (2.1 ± 0.3 Cu atoms per nm²). The Cu-SACs activate peroxide to generate hydroxyl radicals, exhibiting fast kinetics, which are 40-fold higher than those of nanoparticulate Cu catalysts. The Cu₁-functionalized membrane oxidatively removes organic pollutants from feedwater in the presence of peroxide, achieving efficient water purification. We provide evidence that a dual-site cascade mechanism is responsible for in situ regeneration of Cu₁. Specifically, one of the two linked sulfur atoms detaches the oxidized Cu₁ while donating one electron, and an adjacent free thiol rebinds the reduced Cu(I)-S pair, retrieving the Cu-S₂ coordination on the reactive membrane. This work presents a universal, facile approach for engineering robust SACs on water-treatment membranes and broadens the application of SACs to real-world environmental problems.