Binding mechanism of arsenate on rutile (110) and (001) planes studied using grazing-incidence EXAFS measurement and DFT calculation.
Binding mechanism of arsenate on rutile (110) and (001) planes studied using grazing-incidence EXAFS measurement and DFT calculation.
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DOI：
10.1016/j.chemosphere.2014.11.053
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发表时间：
2015-03
期刊：
影响因子：
8.8
通讯作者：
Meiyi Zhang;G. He;G. Pan
中科院分区：
文献类型：
--
作者：
Meiyi Zhang;G. He;G. Pan
污染物分子在不同暴露的晶面上的特性需要最终描述其在矿物表面上的行为。采用掠入射扩展X射线吸收精细结构（GI-EXAFS）谱和周期密度泛函理论（DFT）计算研究了砷酸根在金红石型TiO 2（1 1 0）和（0 0 1）表面上的结构性质和相对稳定性.结果表明，在两种吸附模式下，砷酸根主要在两个表面上形成内球双齿双核（BB）和单齿单核（MM）配合物，但砷酸根在（1 1 0）表面上的取向极角通常小于在（0 0 1）表面上的取向极角. DFT计算表明，（1 1 0）平面比（0 0 1）平面对砷酸根具有更高的亲和力，这表明，对于给定的吸附模式（即，MM或BB结构），小的极角更有利于砷酸盐稳定在金红石表面。
Characterization of contaminant molecules on different exposed crystal planes is required to conclusively describe its behavior on mineral surfaces. Here, the structural properties and relative stability of arsenate adsorbed on rutile TiO2(1 1 0) and (0 0 1) surfaces were investigated using grazing-incidence extended X-ray absorption fine structure (GI-EXAFS) spectra and periodic density functional theory (DFT) calculation. The combined results indicated that arsenate mainly formed inner-sphere bidentate binuclear (BB) and monodentate mononuclear (MM) complexes on both surfaces, but the orientational polar angles of arsenate on the (1 1 0) surface were commonly smaller than that on the (0 0 1) surface for the two adsorption modes. The DFT calculation showed that the (1 1 0) plane had a higher affinity toward arsenate than the (0 0 1) plane, suggesting that, for a given adsorption mode (i.e., MM or BB structure), a small polar angle was more favorable for arsenate stabilized on the rutile surfaces.