Mg（OH）<sub>2</sub>脱水和MgO水化机理的近红外光谱研究,The Journal of Physical Chemistry C

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Mg（OH）₂脱水和MgO水化机理的近红外光谱研究
The Journal of Physical Chemistry C ( IF 3.3 ) Pub Date : 2021-05-18 , DOI: 10.1021/acs.jpcc.1c01470
Atsushi Kondo _{1,

2} , Ryo Kurosawa ₃ , Junichi Ryu ₃ , Masaya Matsuoka ₁ , Masato Takeuchi ₁

Affiliation

通过近红外光谱研究了Mg（OH）_2的脱水和MgO的水合作用的机理。Mg（OH）₂在NIR区域的7339、7306和7157 cm ^–1处显示三个吸收带，这是由于位于边缘和边缘的羟基不同（7339 cm ^–1：OH（e）和OH（c）中的Mg（OH）的角部₂片，7306厘米^-1：OH（吨位于镁的露台上）（OH）₂片，7157厘米^-1：OH（我）位于对Mg（OH）的中间层₂床单）。在从Mg（OH）₂的相变过程中成MgO在约400℃时，层间OH（我的Mg）（OH）₂消失通过脱水反应和OH（吨Mg对（001））面（OH）₂转化成氢键MgO（7309 cm ^–1）（111）平面上的羟基。此外，当MgO与水蒸气在85和50°C（RH 85％）接触时，MgO表面（7360 cm ^–1）的孤立羟基很容易水合形成氢键键合（7309 cm ^–1）。）。当在MgO表面形成单层Mg（OH）₂片时，在7345和7309 cm处观察到OH（e），OH（c）和OH（t）。^–1。随着水合反应的进行，通过实验证实了中间状态，如堆叠数个Mg（OH）₂片，这与OH（t）的减少和中间层OH（i）的自发增加有关。

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Investigation on the Mechanisms of Mg(OH)2 Dehydration and MgO Hydration by Near-Infrared Spectroscopy

The mechanism for the dehydration of Mg(OH)₂ and hydration of MgO was investigated by near-infrared (NIR) spectroscopy. Mg(OH)₂ showed three absorption bands in the NIR region at 7339, 7306, and 7157 cm^–1, due to the different hydroxyl groups (7339 cm^–1: OH(e) and OH(c) located on the edge and corner of the Mg(OH)₂ sheet, 7306 cm^–1: OH(t) located on the terrace of Mg(OH)₂ sheet, 7157 cm^–1: OH(i) located on the interlayer of Mg(OH)₂ sheets). During the phase transition from Mg(OH)₂ to MgO at approximately 400 °C, the interlayer OH(i) of Mg(OH)₂ disappeared by a dehydration reaction and the OH(t) on the (001) plane of Mg(OH)₂ was converted to the hydrogen-bonded hydroxyl groups on the (111) plane of MgO (7309 cm^–1). Furthermore, when MgO was in contact with water vapor at 85 and 50 °C (RH 85%), the isolated hydroxyl groups of the MgO surface (7360 cm^–1) were easily hydrated to form hydrogen-bonded ones (7309 cm^–1). When a monolayer Mg(OH)₂ sheet was formed on the MgO surface, OH(e), OH(c), and OH(t) were observed at 7345 and 7309 cm^–1. As the hydration reaction proceeded, the intermediate state like stacking of several Mg(OH)₂ sheets, which are related to the decrease in the OH(t) and the spontaneous increase in the interlayer OH(i), was experimentally confirmed.

更新日期：2021-05-27

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