Sulfone Molecular Switch Enables Direct Two-Electron Uranium Photoreduction in Programmed Covalent Organic...

Area of Science:

• Materials Science
• Photocatalysis
• Sustainable Energy

Background:

• Photocatalytic uranium extraction is crucial for sustainable nuclear energy.
• Current methods are limited by inefficient indirect pathways (superoxide-mediated).
• These pathways exhibit slow kinetics, oxygen dependence, and poor selectivity.

Purpose of the Study:

• To engineer a molecular switch for a direct two-electron transfer pathway in photocatalytic uranium reduction.
• To enhance uranium extraction efficiency, kinetics, and selectivity from seawater.
• To develop a versatile strategy for solar-driven resource recovery.

Main Methods:

• Edge-hanging engineering of a covalent organic framework (COF) with a molecular sulfone switch.
• Synthesis of the optimized Py-DaSO-COF material.
• Experimental and theoretical studies (including DFT) to elucidate the mechanism.

Main Results:

• The Py-DaSO-COF achieved a uranium extraction capacity of 21.25 mg g⁻¹ in natural seawater.
• Demonstrated rapid kinetics and high selectivity against vanadium ions.
• The sulfone switch facilitated direct electron transfer, suppressed superoxide generation, and stabilized uranium intermediates.

Conclusions:

• A molecular-level sulfone switch effectively shifts photocatalytic pathways for enhanced uranium photoreduction.
• This strategy offers a significant advancement for efficient and selective uranium extraction from seawater.
• The developed molecular engineering approach has broad implications for solar-driven resource recovery.