Zheng Fang

The single‐electron photocatalytic reduction of molecular oxygen to superoxide radicals (O ₂ ^•− ) represents the rate‐determining step in environmental photochemistry, yet achieving high selectivity toward this pathway remains a formidable challenge. Here, we introduce a conceptually driven orbital‐hybridization strategy to precisely regulate the d/p orbitals of polymeric phenylethynylcopper (PECu) through chlorine doping. Rather than acting as a conventional heteroatom dopant, Cl ⁻ serves as an “orbital fine‐tuner”, enhancing the coordination polarization of C≡C─Cu units and shortening the Cu─Cu ladder spacing to construct an efficient metal–metal charge‐transfer (MMCT) channel. This interfacial electronic engineering markedly improved d/p‐band center proximity (Δ ε _d‐p ), thereby optimizing the adsorption and activation of O ₂ intermediates at alkyne active sites. The optimized PCC photocatalyst exhibits exceptional selectivity for the O ₂ → O ₂ ^•− single‐electron reduction pathway, achieving a superoxide yield of 471.38 µmol/L and significantly enhanced water decontamination performance. This work extends conventional band‐center engineering from activity optimization to highly preferential single‐electron oxygen activation by identifying d/p‐band‐center proximity as a key electronic descriptor governing selective single‐electron O ₂ reduction.

The single‐electron photocatalytic reduction of molecular oxygen to superoxide radicals (O ₂ ^•− ) represents the rate‐determining step in environmental photochemistry, yet achieving high selectivity toward this pathway remains a formidable challenge. Here, we introduce a conceptually driven orbital‐hybridization strategy to precisely regulate the d/p orbitals of polymeric phenylethynylcopper (PECu) through chlorine doping. Rather than acting as a conventional heteroatom dopant, Cl ⁻ serves as an “orbital fine‐tuner”, enhancing the coordination polarization of C≡C─Cu units and shortening the Cu─Cu ladder spacing to construct an efficient metal–metal charge‐transfer (MMCT) channel. This interfacial electronic engineering markedly improved d/p‐band center proximity (Δ ε _d‐p ), thereby optimizing the adsorption and activation of O ₂ intermediates at alkyne active sites. The optimized PCC photocatalyst exhibits exceptional selectivity for the O ₂ → O ₂ ^•− single‐electron reduction pathway, achieving a superoxide yield of 471.38 µmol/L and significantly enhanced water decontamination performance. This work extends conventional band‐center engineering from activity optimization to highly preferential single‐electron oxygen activation by identifying d/p‐band‐center proximity as a key electronic descriptor governing selective single‐electron O ₂ reduction.

In situ chemical oxidation (ISCO) is widely used for groundwater remediation, whereas the influence of aquifer heterogeneity, that is, the difference in physical structure and chemical compositions, on oxidant retention and consumption remains poorly understood. In low-permeability lens-containing sand columns, we found that the retention and consumption of oxidant (KMnO4) were largely influenced by the chemical reactivity of the lens besides the well-known permeability. Inert lens (represented by kaolin) mainly altered the transport pathways of oxidant, whereas chemically reactive lenses (represented by real sediments with different electron-donating capacities) further enhanced the retention and consumption within the lenses. A higher electron-donating capacity led to more oxidant retention and consumption. Moreover, the reduced components released from the reactive lens could also increase the oxidant consumption. This study highlights the importance of chemical reactivity besides the physical structure of lenses in heterogeneous aquifers for oxidant transport, retention, and consumption and also implicates the consideration of chemical reactivity for designing the injection dosages and position of oxidants in ISCO remediation.