Synergistic phosphoryl group and sulfur vacancy engineering on MoS₂ nanosheets for highly efficient electrochemical uranium extraction

Abstract

Extracting uranium from nuclear wastewater is critical for environmental protection and sustainable nuclear energy. Conventional electrochemical methods suffer from limited adsorption capacity and slow kinetics. In this work, phosphorus-oxygen co-doped MoS₂ nanosheets with sulfur vacancies were designed and synthesized as an advanced electrode material. Synergistic effects from phosphoryl groups and sulfur vacancies enhance uranyl ion capture via coordination, electrostatic attraction, and electrochemical reduction. At −0.9 V applied potential, PO-MoS₂ achieves a high adsorption capacity of 501.79 mg g⁻¹, significantly exceeding the 120.85 mg g⁻¹ of O-MoS₂ at pH=5.0, and removes 99.5 % U (VI) within 20 min. The material retains over 82.0 % efficiency after 6 cycles. Mechanistic studies confirm U(VI) reduction to insoluble U(IV) species, while density functional theory calculations validate strong uranyl ions -phosphoryl coordination. This strategy provides a high-performance electrode for efficient uranium extraction.