A Z-scheme heterojunction ZnCdS/P2W12Fe9AO nanocomposite based on an adsorption–photoreduction synergistic strategy for uranium reduction†

Abstract

Photocatalytic uranium reduction has been proposed as an effective method for treating nuclear wastewater due to its advantages of cleanliness, energy efficiency, and convenience in application. In this study, a Z-scheme heterojunction, ZnCdS-P₂W₁₂Fe₉AO, was designed and synthesized for achieving efficient uranium reduction via an adsorption–photoreduction synergistic strategy. DFT calculation results demonstrated that polyoxometalates modified with amidoxime groups exhibited exceptional uranium adsorption performance. The construction of the Z-scheme heterojunction enhanced visible light absorption, facilitated electron transfer, and promoted the separation of photogenerated electrons and holes. Finally, ZnCdS-P₂W₁₂Fe₉AO achieved a uranium removal rate of 97.7% (610.6 mg g⁻¹ under light irradiation) without the addition of any sacrificial agent. Meanwhile, ZnCdS-P₂W₁₂Fe₉AO maintained good stability and reusability. This study offers new insights and perspectives for advancing research on photocatalytic uranium reduction.