Li Pei-Hua, Song Zong-Yin, Xiao Xiang-Yu, Liang Bo, Yang Meng, Chen Shi-Hua, Liu Wen-Qing, Huang Xing-Jiu
Key Laboratory of Environmental Optics and Technology, And Environmental Materials and Pollution Control Laboratory, Institute of Solid State Physics, HFIPS, Chinese Academy of Sciences, Hefei 230031, PR China.
Key Laboratory of Environmental Optics and Technology, And Environmental Materials and Pollution Control Laboratory, Institute of Solid State Physics, HFIPS, Chinese Academy of Sciences, Hefei 230031, PR China; Department of Materials Science and Engineering, University of Science and Technology of China, Hefei 230026, PR China.
J Hazard Mater. 2023 Jan 15;442:130122. doi: 10.1016/j.jhazmat.2022.130122. Epub 2022 Oct 4.
Mutual interference issues between heavy metal ions tremendously affect the detection reliability and accuracy in water quality analysis, especially the serious interference of Cu(II) on the detection of As(III) is greatly hard to overcome, which needs to be solved urgently. Herein, iron single-atom catalysts with different coordination structures of FeNC and FeNP are constructed to selectively catalyze the detection of As(III) in the coexistence of Cu(II). FeNP achieves a high sensitivity of 3.90 µA ppb toward As(III) in NHCl/NH·HO electrolyte (pH 8.0), completely avoiding Cu(II)-interference. Moreover, the turnover frequency (TOF) of FeNP is an order of magnitude higher than that of FeNC. X-ray absorption fine structure (XAFS) spectroscopy and density functional theory (DFT) calculations demonstrate that an As-O bond of HAsO is broken by the strong affinities between both P and O atoms and Fe and As atoms, and HAsO are preferentially reduced by FeNP during adsorptive process. Meanwhile, the low reaction energy barrier of the rate-determined step for As(III) reduction over FeNP also accelerates the deposition of As(III) and enhances its response signals. The free-Cu(II) are difficult to adsorb on FeNP and do not compete with As(III) for Fe active sites, which contributes to the excellent anti-Cu(II) interference capability.
重金属离子之间的相互干扰问题极大地影响了水质分析中的检测可靠性和准确性，尤其是Cu(II)对As(III)检测的严重干扰极难克服，这亟待解决。在此，构建了具有不同配位结构FeNC和FeNP的铁单原子催化剂，以选择性催化在Cu(II)共存情况下对As(III)的检测。在NHCl/NH·HO电解质（pH 8.0）中，FeNP对As(III)实现了3.90 µA ppb的高灵敏度，完全避免了Cu(II)的干扰。此外，FeNP的周转频率（TOF）比FeNC高一个数量级。X射线吸收精细结构（XAFS）光谱和密度泛函理论（DFT）计算表明，HAsO的As-O键因P原子与O原子以及Fe原子与As原子之间的强亲和力而断裂，并且在吸附过程中HAsO被FeNP优先还原。同时，在FeNP上As(III)还原的速率决定步骤的低反应能垒也加速了As(III)的沉积并增强了其响应信号。游离的Cu(II)难以吸附在FeNP上，并且不与As(III)竞争Fe活性位点，这有助于其优异的抗Cu(II)干扰能力。
