Jian-Ding Qiu

Enzymatic confined microenvironments cooperatively modulate reactive oxygen species (ROS) dynamics to enhance biocatalytic efficiency. Drawing inspiration from this natural mechanism, we developed covalent organic frameworks (COFs) with programmable nanoscale confinement, achieved via topology‐directed assembly. This design enables precise spatiotemporal regulation of ROS generation and scavenging, thereby facilitating highly efficient and unprecedented dual‐potential electrochemiluminescence (ECL). The resulting confined COF architecture exhibits enhanced electronic coupling, attributable to dense π‐stacking, and a well‐ordered, continuous hydrogen‐bonding network templated by functionalized pore walls. By mimicking enzymatic proton‐coupled electron transfer (PCET), the confined environment not only promotes site‐specific ROS generation from electrocatalytic water oxidation but also directs ROS‐mediated redox consumption pathways toward selective population of emissive excited states. As a result, we report the first dual‐potential ECL emission in a COF‐based system, achieving cathodic and anodic ECL efficiencies of 40.5% and 21.2%, respectively, representing 11.3‐ and 8.2‐fold enhancements relative to analogous unconfined COFs. Moreover, size‐selective binding of UO ₂ ²⁺ within the confined pores provides direct experimental evidence for confinement‐enabled ROS regulation, yielding quantitative, analyte‐responsive ECL signals. Collectively, these findings establish a broadly applicable principle of confinement‐directed reactivity, grounded in mechanistic understanding and offering a rational, structure‐function‐guided strategy for the design of advanced functional materials.

Enzymatic confined microenvironments cooperatively modulate reactive oxygen species (ROS) dynamics to enhance biocatalytic efficiency. Drawing inspiration from this natural mechanism, we developed covalent organic frameworks (COFs) with programmable nanoscale confinement, achieved via topology‐directed assembly. This design enables precise spatiotemporal regulation of ROS generation and scavenging, thereby facilitating highly efficient and unprecedented dual‐potential electrochemiluminescence (ECL). The resulting confined COF architecture exhibits enhanced electronic coupling, attributable to dense π‐stacking, and a well‐ordered, continuous hydrogen‐bonding network templated by functionalized pore walls. By mimicking enzymatic proton‐coupled electron transfer (PCET), the confined environment not only promotes site‐specific ROS generation from electrocatalytic water oxidation but also directs ROS‐mediated redox consumption pathways toward selective population of emissive excited states. As a result, we report the first dual‐potential ECL emission in a COF‐based system, achieving cathodic and anodic ECL efficiencies of 40.5% and 21.2%, respectively, representing 11.3‐ and 8.2‐fold enhancements relative to analogous unconfined COFs. Moreover, size‐selective binding of UO ₂ ²⁺ within the confined pores provides direct experimental evidence for confinement‐enabled ROS regulation, yielding quantitative, analyte‐responsive ECL signals. Collectively, these findings establish a broadly applicable principle of confinement‐directed reactivity, grounded in mechanistic understanding and offering a rational, structure‐function‐guided strategy for the design of advanced functional materials.

Photocatalytic uranium reduction via the superoxide radical (•O ₂ ⁻ ) pathway is a sustainable route, but its efficiency is constrained by rapid charge recombination and poor O ₂ activation. Herein, we develop a ligand engineering strategy to construct a series of Ni‐diketimine‐linked COFs by varying the diketone units directly coordinated to the Ni centers, enabling precise tuning of the Ni electronic state. The acenaphthylene‐1,2‐dione‐derived Ni‐COF‐E reaches a peak optimum within the present series, termed the “Zenith electronic state”, as evidenced by the highest ligand‐to‐metal charge transfer (0.584 e) and the largest charge transfer distance (1.700 Å) among the three Ni‐COFs in the S ₁ excited state. This zenith electron density balances efficient photogenerated electron capture with enhanced O ₂ adsorption and a lowered barrier for •O ₂ ⁻ formation, which is corroborated by combined experimental and theoretical analyses. Consequently, Ni‐COF‐E delivers a record •O ₂ ⁻ generation rate of 8.48 µM h ⁻¹ and achieves >99% uranium removal from real wastewater. This work establishes direct ligand engineering as a powerful strategy for tuning single‐metal sites in COFs and positions the Zenith electronic state as a new design principle for •O ₂ ⁻ ‐mediated photocatalysis.

The photocatalytic performance of covalent organic frameworks (COFs) is governed not only by the nature of their building blocks and linkages, but also by the positional arrangement of functional groups. Here, cyano positional isomerism was employed to construct a pair of sp2-carbon-linked covalent organic frameworks (COFs), BD-BT and BD-TB, as a platform for photocatalytic uranium extraction. In BD-BT, the cyano groups are incorporated into cyano-substituted vinylene linkages, whereas in BD-TB they are directly conjugated with the aromatic C3 nodes. Such positional variation produces distinct local electronic structures and excited-state characteristics. Compared with BD-BT, BD-TB exhibits a lower exciton binding energy (37.1 meV) and enhanced charge separation and interfacial charge transfer. The cyano-containing sites also favor uranyl enrichment, providing a favorable interface for subsequent photogenerated electron driven reactions. Without sacrificial agents, BD-TB achieves a uranium capture capacity of 1231.6 mg g⁻¹, approximately 1.5 times that of BD-BT, and maintains 92.3% uranium removal in real rare-earth tailings. These results demonstrate that cyano positional isomerism provides an effective strategy for regulating charge behavior and designing high-performance COF photocatalysts for uranium extraction from complex radioactive wastewater.

Th(IV) poses severe radioactive hazards once released into the environment due to its long half-life and potential bioaccumulation. Therefore, the development of multifunctional materials capable of simultaneous detection and removal of Th(IV) becomes an urgent research priority. Herein, by introducing pyrazole-functionalized isonicotinic acid monomers, a hydrogen-bonded organic framework (DPIA-HOF) with strong stability under acidic conditions was successfully constructed by a simple solvent evaporation method. The π···π interactions and multiple hydrogen bonds in DPIA-HOF suppress the rotation and vibration of the intramolecular pyrazole ring, thereby stabilizing the three-dimensional monoclinic structure and significantly improving the rigidity of the framework. Experimental and theoretical calculations indicate that DPIA-HOF can achieve sensitive fluorescent detection of Th(IV) via photoinduced electron transfer (PET) mechanism, with a detection limit of 5.5 ppb. Furthermore, the coordination interactions between Th(IV) and nitrogen/oxygen atoms enable selective adsorption and efficient removal of Th(IV) with rapid kinetics and excellent selectivity that is applicable to real rare earth tailings leachate treatment. This work proposes a new strategy to construct functionalized HOFs for the selective detection and efficient removal of radioactive nuclides.

Hydrogen‐bonded organic frameworks (HOFs) provide an ideal green and sustainable material platform for the efficient removal of thorium (Th(IV)). However, traditional solvent‐mediated HOFs exhibit poor structural stability and hydrophobicity in aqueous media. In this study, water (H ₂ O), featuring well‐defined molecular geometry and directional hydrogen‐bonding capability, was employed as a structural modulator to enable controlled assembly of two 2,7‐bis(4H‐1,2,4‐triazole‐4‐yl)benzo[lmn][3,8]phenol‐1,3,6,8(2H,7H)‐tetraketone (NDIT)‐based HOFs, NDIT‐HOF‐1 and NDIT‐HOF‐2, which exhibit distinct hydrogen‐bond topologies and pore dimensions (4.86 Å and 1.80 Å, respectively). The concentration of water governs hydrogen‐bonding kinetics: at low concentrations, water acts as a directional bridging unit that strengthens intermolecular coupling, at elevated concentrations, it undergoes preferential self‐aggregation, thereby diminishing the efficacy of interframework hydrogen‐bonding connections and leading to pronounced differences in pore aperture and surface polarity. Owing to its size‐complementary architecture and enhanced hydrophilicity, NDIT‐HOF‐1 demonstrates a 2.7‐fold higher Th(IV) uptake capacity and a 10‐fold faster adsorption kinetics rate compared with NDIT‐HOF‐2. Collectively, this work establishes water as a programmable, atomic‐scale structure modulator in HOF design and provides direct experimental evidence that precise control over framework structure regulation is critical for optimizing actinide ion capture performance.

Inspired by the modulatable nanozymatic activity of covalent organic frameworks (COFs) by single-stranded DNA (ssDNA), herein, we developed a versatile platform for sensitive/specific colorimetric detection and efficient adsorption of UO22+ based on DNA aptamer-functionalized COFs. Three COFs with varying alkyne contents (Py-BDA, Py-BDA-BPTA, and Py-BPTA) were synthesized, followed by precisely covalent immobilization of UO22+-specific DNA aptamers via click chemistry. These COFs possess intrinsic oxidase-mimicking activity capable of catalyzing TMB oxidation to oxTMB, and the DNA aptamer covalent modification can regulate the enzymatic activity of COFs, with the most suppressing effect for Py-BDA-BPTA. The subsequent UO22+ binding can significantly restore the nanozymatic activity of Py-BDA-BPTA by charge neutralization. This “off-on” switching mechanism enabled sensitive and selective UO22+ detection with a low limit of detection (LOD) about 10 nM (3σ). Moreover, the DNA aptamer-functionalized COFs can be applied for efficient adsorption and removal of UO22+ with rapid kinetics and excellent cycling stability. This study provides novel insights into the postmodification of COFs by biomacromolecules to modulate their mimic enzymatic activity for sensing and adsorption applications.

Covalent organic frameworks (COFs) offer precise spatial control over catalytically active sites due to their ordered, crystalline structures. This control directly governs site accessibility and interfacial charge transfer, both critical for electrochemiluminescence (ECL) via multistep energy conversion. To decouple and systematically investigate spatial effects independent of chemical composition, we introduce an isomeric COF design strategy, yielding two structurally distinct yet chemically identical frameworks: BTT-DAPQ and BTT-DAAQ. These feature ortho- and para-positioned ketone groups on the same diamine linker, respectively, thereby enabling atomic-level control over active-site distance, relative orientation, and local cooperative microenvironment. In BTT-DAPQ, the ortho-ketone motif promotes dipole-driven antiparallel π-stacking, which enhances intralayer charge delocalization and increases surface exposure of redox-active carbonyl sites. This synergistic structural advantage strengthens interfacial interaction with the coreactant S2O82–, facilitating its efficient activation and subsequent sulfate radical (SO4•-) generation. Consequently, BTT-DAPQ delivers a 7.12-fold higher ECL intensity than its para-isomeric counterpart. Leveraging this amplified signal transduction, we further developed a selective uranyl ions (UO22+) sensing platform: the strong Lewis acidity of UO22+ drives preferential coordination to oxygen-rich sites in the framework, competitively inhibiting S2O82– activation and inducing up to 96.23% ECL quenching. The assay exhibits a broad linear dynamic range (10–5000 nM) and an ultralow detection limit of 2.53 nM. Collectively, this study establishes that nanoscale spatial organization, not merely chemical identity, is a decisive factor in governing ECL mechanisms.

Highly soluble and mobile U(VI) renders rare-earth tailing uranium wastewater hard to remediate. Conventional reduction treatments demand extra energy, and show weak removal efficiency in strongly acidic conditions, restricting their practical application. Herein, we present a rationally engineered, self-assembled phytate-Fe-polyaniline (PA-Fe-PANI) composite that functions as an autonomous microscale redox reactor, enabling concurrent adsorption and catalytic reduction of UVI. The material leverages an intrinsic, self-sustaining Fe2+/Fe3+ redox cycle to drive the in situ reduction of adsorbed UVI to immobile tetravalent UIV without requiring any external energy input. PA-Fe-PANI shows outstanding uranium adsorption performance over pH 1.0–7.0, reaching a maximum capacity of 130.70 mg/g under the strongly acidic condition at pH 1.0. Tests on actual high-ionic-strength rare-earth tailings wastewater with complicated coexisting ions confirm the composite removes 96.8% uranium. This study develops an energy-neutral, scalable, and chemically stable approach to effectively immobilize uranium in strongly acidic complex industrial wastewater.