Fabrication of cobalt–nitrogen–carbon composite anchored on MXene for efficient photoelectrocatalytic reduction of U(VI)

Photoelectrocatalytic (PEC) reduction of soluble U(VI) to insoluble U(IV) represents a highly promising strategy for uranium removal. The design of photoelectrode materials with superior photoelectrochemical performance is crucial for enhancing PEC efficiency. In this study, an MXene-supported Co-NC (Co-NC/MXene) photoelectrode was successfully fabricated through electrostatic self-assembly. Compared to individual electrocatalytic (EC) and photocatalytic (PC) systems, the PEC system achieved an optimal U(VI) removal efficiency of 99.1 % with a rate constant of 0.116 min −1 , demonstrating reaction rates 13.4 times and 29.3 times higher than those of EC and PC systems, respectively. The Co-NC/MXene electrode exhibited exceptional adsorption capacity (3993.54 mg g −1 for 500 ppm) and maintained over 80 % removal efficiency after six consecutive cycles, highlighting its outstanding stability. This work provides novel insights into the application of MOF-derived/MXene materials for highly efficient U(VI) removal from aqueous solutions.