SCIENCE CHINA Materials•2026•DOI: 10.1007/s40843-025-3885-8
Photocatalytic production of hydrogen peroxide (H2O2) via oxygen reduction reaction (ORR) and water oxidation reaction (WOR) from water and air offers a sustainable alternative to conventional anthraquinone processes. However, the intrinsic kinetic mismatch—fast ORR (microseconds to milliseconds) versus sluggish WOR (seconds)—limits overall efficiency. Here, we report aliphatic acylhydrazone covalent organic frameworks (AA-COFs) synthesized by coupling aliphatic hydrazides with benzotrithiophene motifs via acylhydrazone linkages. The pore walls are decorated with abundant S, O, and N heteroatoms, enhancing affinity toward both O2 and H2O, thereby improving the kinetics of both half-reactions. Through single-carbon atomic engineering, the optimized AA-COF achieves a trade-off between ORR and WOR kinetics, enabling efficient overall H2O2 photosynthesis from water and air without sacrificial agents. The material exhibits a H2O2 production rate of 4777 μmol g−1 h−1 and an O2 utilization/conversion efficiency of 99.3%. This work demonstrates that rational design of heteroatom-rich COFs can synchronize ORR and WOR, overcoming a major bottleneck in artificial photosynthesis.
SCIENCE CHINA Materials•2026•DOI: 10.1007/s40843-025-3971-6
Photocatalytic reduction of soluble U(VI) to insoluble U(IV) is a pivotal technology for uranium remediation and resource recovery. However, conventional covalent organic frameworks (COFs) suffer from short-range electron transport, leading to rapid electron-hole recombination and limited efficiency. Here, we report the rational design of anthraquinone-based COFs with donor-acceptor (D-A) architectures, employing 2,4,6-triformylphloroglucinol (TP) as the donor and 1,4-diaminoanthraquinone (1,4-DQ) or 1,5-diaminoanthraquinone (1,5-DQ) as the acceptor. By varying the connection mode of the building units, the electron transfer distance is systematically extended, effectively suppressing charge recombination. Among the synthesized COFs, ECUT-COF-152 exhibits optimal photocatalytic activity under visible light, achieving 100% U(VI) removal with a maximum reduction capacity of 1950 mg g−1. This work demonstrates that precise tuning of the D-A structure and electron transfer pathways is an effective strategy to enhance the photocatalytic performance of COFs for uranium reduction, offering insights for the design of efficient materials for nuclear waste treatment.
SCIENCE CHINA Materials•2026•DOI: 10.1007/s40843-026-4282-y
Recovering gold from electronic waste (e-waste) is critical for sustainable resource management, yet conventional adsorbents suffer from poor acid stability and slow kinetics. Here, we report an acid-resistant cationic covalent organic framework (COF), TAPT-TNV, synthesized via irreversible Zincke reaction. TAPT-TNV exhibits exceptional stability in concentrated acids, retaining crystallinity and porosity after exposure to 12 M HCl and 6 M HNO3. The cationic skeleton, balanced by Cl− counterions, enables rapid and selective capture of AuCl4− through anion exchange, complemented by chemical reduction at triazine units. Adsorption kinetics are fast, reaching equilibrium within 30 minutes, with a maximum capacity of 1835.5 mg g−1 at pH 1. In real e-waste leachate, TAPT-TNV achieves a gold recovery rate of 99.42%, demonstrating high selectivity over competing metal ions. This work introduces a robust COF platform for precious metal recovery, addressing the limitations of hydrolytically unstable frameworks.