Despite that two-dimensional transition metal carbides and carbonitrides (MXenes) are burgeoning candidates for remediation of environmental pollutants, the construction of robust functionalized MXene nanosheets with a high affinity for target heavy metal ions and radionuclides remains a challenge. Here we report the successful placement of amidoxime chelating groups on Ti₃C₂T_x MXene surface by diazonium salt grafting. The introduction of amidoxime functional groups significantly enhances the selectivity of Ti₃C₂T_x nanosheets for uranyl ions and also greatly improves their stability in aqueous solution, enabling efficient, rapid, and recyclable uranium extraction from aqueous solutions containing competitive metal ions. Benefiting from the excellent conductivity of MXenes, the amidoxime functionalized Ti₃C₂T_x nanosheets show outstanding electrochemical performance such that when loaded on carbon cloth the application of an electric field increases the uranium adsorption capacity from 294 to 626 mg/g, outperforming all organic electrochemical sorption materials reported previously. The present work provides an effective strategy to functionalize MXene nanosheets with fundamental implications for the design of MXene-based selective electrosorption electrode materials.

中文翻译：

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芳基重氮鎓辅助的MXene酰胺化反应通过电化学吸附增强水的稳定性和铀基螯合

尽管二维过渡金属碳化物和碳氮化物（MXenes）迅速成为了修复环境污染物的候选材料，但是构建对目标重金属离子和放射性核素具有高亲和力的坚固的功能化MXene纳米片仍然是一个挑战。在这里我们报告通过重氮盐接枝成功地将Ti胺肟螯合基团放置在Ti ₃ C ₂ T _x MXene表面上。引入mid肟肟官能团可显着提高Ti ₃ C ₂ T _x的选择性用于铀酰离子的纳米片，还大大提高了其在水溶液中的稳定性，从而能够从含有竞争性金属离子的水溶液中高效，快速且可回收地提取铀。得益于MXenes优异的电导率，the胺肟官能化的Ti ₃ C ₂ T _x纳米片表现出出色的电化学性能，因此，当负载在碳布上时，施加电场可使铀的吸附容量从294 mg / g增加到626 mg / g，优于所有有机电化学吸附材料已有报道。本工作提供了一种有效的策略，以功能化MXene纳米片具有基于MXene的选择性电吸附电极材料的设计的基本含义。