Abstract
The electrocatalytic role of Ti_3C_2Tx MXene in U(VI) immobilization has remained largely unexplored. Herein, a binder-free electrode (TiMX/CNTCOOH) is designed and its exceptional performance in electrochemically U(VI) extraction under square-wave exchange (SWE) is demonstrated. The incorporation of carboxylated carbon nanotubes (CNT-COOH) as a rigid spacer not only enhances structural disorder but also exposes abundant undercoordinated Ti edge sites and induces bond stretching (Ti-O and O-H), further boosting intrinsic catalytic activity. This synergistic effect interaction lowers the energy barrier of the rate-determining step by 0.82 eV. Through integrated in situ Raman spectroscopy and density functional theory calculations, the dynamic U(VI)/U(V) transition is directly captured at Ti-active edge sites, representing the first mechanistic elucidation of MXene-based electrocatalysis for uranium. Consequently, the TiMX/CNT-COOH cathode achieves an impressive uranium extraction capacity of 1,1719.96 mg g~(-1) with excellent cycling stability. This work offers fundamental insights into the electrocatalytic mechanism and provides a strategic framework for designing large-scale electroactive materials for uranium recovery from wastewater.
NETL
NSTL
Wiley