Study on the radiation catalytic reduction of perrhenate in covalent organic framework nanoreactors

The reduction of high-valent metal oxysalts to lower valent states represents a critical pathway for their resource utilization. However, the inherently low redox potentials of oxysalts such as perrhenate (ReO4–) pose significant challenges to conventional reduction methods. This study demonstrates efficient γ-ray-driven radiation catalytic reduction of ReO4– within olefin-linked covalent organic framework nanoreactors incorporating transition metal centers (M-COF). Owing to spatial confinement effects and tailored electronic structures, the catalyst facilitates a unique three-electron (3e–) transfer pathway, achieving near-quantitative selectivity for ReO2 production with a remarkable energy efficiency of 42.1 mmol/MJ. Mechanism investigations reveal that hydrated electrons (eaq–), generated via water radiolysis, participate in the electron transfer process and promote the formation of key [M-O(O)-Re] intermediates. This work expands the application of COF materials in radiation chemistry and offers a novel strategy for treating redox-inert pollutants.