Strongly oxidizing ·OH can non-selectively degrade various organic pollutants, but how to selectively generate ·OH is a great challenge. In this study, the directed generation of ·OH was achieved based on Ni–Ca metastable–nonmetastable bimetallic sites, Ni²⁺/Ni³⁺ valence cycling provided electrons for ·OH generation induced by the non-variable Ca-based sites, which constructed a nearly 100% selective generation pathway of ·OH (O₃ → HO₃/HO₂ → OH). The antibiotic pefloxacin could be completely removed in 15 min, and the COD removal efficiency for other hard-to-degrade pollutants such as oxalic acid and chlorobenzoic acid could reach more than 90%. Ni doping significantly increased the oxygen vacancy and Lewis acid content, and DFT calculations showed that Ni–Ca dual-site had a lower reaction energy barrier and the complexed hydroxyl radical intermediate *OO had a higher spin density (−0.6), which was more favorable for the generation of ·OH. Therefore, this study provides new ideas for efficient treatment of actual wastewater.

中文翻译：

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Ni-Ca亚稳态-非亚稳态双金属位点诱导·OH定向生成和高效水净化


强氧化性·OH可以非选择性地降解多种有机污染物，但如何选择性地生成·OH是一个巨大的挑战。本研究基于Ni-Ca亚稳态-非亚稳态双金属位点实现了·OH的定向生成，Ni ²⁺ /Ni ³⁺价态循环为非可变Ca基位点诱导·OH的生成提供了电子，构建了近100%选择性生成·OH的途径（O ₃ → HO ₃ /HO ₂ → OH）。抗生素培氟沙星15分钟即可完全去除，对草酸、氯苯甲酸等其他难降解污染物的COD去除率可达90%以上。 Ni掺杂显着增加了氧空位和路易斯酸含量，DFT计算表明Ni-Ca双位点具有较低的反应能垒，络合的羟基自由基中间体*OO具有较高的自旋密度（-0.6），有利于·OH的生成。因此，本研究为实际废水的高效处理提供了新的思路。