Ice nucleation activity of iron oxides via immersion freezing and an examination of the high ice nucleation activity of FeO
Ice nucleation activity of iron oxides via immersion freezing and an examination of the high ice nucleation activity of FeO
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DOI：
10.1039/d0cp04220j
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发表时间：
2021-02-07
影响因子：
3.3
通讯作者：
Freedman, Miriam Arak
中科院分区：
文献类型：
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作者：
Chong, Esther;Marak, Katherine E.;Freedman, Miriam Arak
非均匀冰成核是大气中的一个常见过程，但人们对不同的表面特征对冰成核的促进作用知之甚少。我们已经使用了一系列的铁氧化物作为模型系统，以研究晶格失配和缺陷的作用引起的研磨冰成核活性。氧化铁包括方铁矿（FeO）、赤铁矿（Fe 2 O3）、磁铁矿（Fe 3 O 4）和针铁矿（FeOOH）。通过X射线衍射（XRD）和比表面积（BET）测量对铁氧化物进行表征。使用环境室进行浸没冷冻实验。其中，铁尖晶石（FeO）具有最高的冰成核活性，这归因于其与六方冰的低晶格失配和球磨后Fe-OH的暴露。MnO和浮氏体（FeO）与研磨和筛分样品的比较研究表明，物理缺陷单独导致冰成核活性仅略有增加。尽管在分子式和表面基团的差异，赤铁矿（Fe 2 O3），磁铁矿（Fe 3 O 4），针铁矿（FeOOH）有类似的冰成核活动，这可能是由于他们的高晶格失配的六方冰。这项研究提供了一个良好的异质冰核的特性进一步了解，更一般地说，有助于阐明气溶胶粒子和云中的冰粒子之间的相互作用。
Heterogeneous ice nucleation is a common process in the atmosphere, but relatively little is known about the role of different surface characteristics on the promotion of ice nucleation. We have used a series of iron oxides as a model system to study the role of lattice mismatch and defects induced by milling on ice nucleation activity. The iron oxides include wustite (FeO), hematite (Fe2O3), magnetite (Fe3O4), and goethite (FeOOH). The iron oxides were characterized by X-ray diffraction (XRD) and Brunauer-Emmett-Teller (BET) surface area measurements. The immersion freezing experiments were performed using an environmental chamber. Wustite (FeO) had the highest ice nucleation activity, which we attribute to its low lattice mismatch with hexagonal ice and the exposure of Fe-OH after milling. A comparison study of MnO and wustite (FeO) with milled and sieved samples for each suggests that physical defects alone result in only a slight increase in ice nucleation activity. Despite differences in the molecular formula and surface groups, hematite (Fe2O3), magnetite (Fe3O4), and goethite (FeOOH) had similar ice nucleation activities, which may be attributed to their high lattice mismatch to hexagonal ice. This study provides further insight into the characteristics of a good heterogeneous ice nucleus and, more generally, helps to elucidate the interactions between aerosol particles and ice particles in clouds.