Synthesis, characterization and reactivity study of nanoscale magnesium oxide
Synthesis, characterization and reactivity study of nanoscale magnesium oxide
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DOI：
10.1016/j.molcata.2007.04.039
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发表时间：
2007-09-03
影响因子：
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通讯作者：
Glisenti, Antonella
中科院分区：
文献类型：
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作者：
Khairallah, Fares;Glisenti, Antonella
采用“水湿化学法（MgO-OX）”和“表面活性剂法（MgO-BR：Brij 56为表面活性剂，MgO-TR：Triton 100-X为表面活性剂）"制备了不同的纳米氧化镁（MgO）样品。采用X射线光电子能谱（XPS）、X射线衍射（XRD）、漫反射红外傅里叶变换（DRIFT）和热重分析（TGA）对样品进行了表征。从所进行的分析中，注意到羟基和碳酸酯基团的量随合成程序而不同。与MgO-BR样品的16 nm和MgO-TR样品的18 μ相比，MgO-OX样品中的颗粒的估计尺寸较小（约13 nm）。利用DRIFT谱对MgO纳米粒子的反应性进行了研究。以甲醇和一氧化碳为原料考察了MgO的催化活性。在相对较低的温度下，甲醇分解成甲醇盐物质。在较高温度下，观察到形成不同的氧化产物（甲酸盐和甲酸、CO和CO2）。MgO-OX比MgO-TR/BR样品显示出更好的氧化性能。此外，碱性和酸性网站分别使用二氧化碳和吡啶进行了研究，得到的结果表明不同样品中的酸性/碱性网站的不同分布。(c)2007年由Elsevier B. V.出版。
In this study, different samples of nanoscale magnesium oxide (MgO) were synthesized using "aqueous wet chemical method (MgO-OX)" and "surfactant method (MgO-BR: stafactant used Brij 56, MgO-TR: sw ctant used Triton 100-X)". The samples were then characterized by: X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), diffuse reflectance infrared Fourier-transform (DRIFT) spectroscopy and Thermogravimetric analysis (TGA). From the analyses performed, it was noticed that the amount of hydroxyl and carbonate groups differs as a function of the synthesis procedure. The estimated dimensions of the particles are smaller in the MgO-OX sample (around 13 nm) compared to the 16 nm of the MgO-BR samples and 18 mu of the MgO-TR samples. Studies on the reactivity of MgO nanoparticles were performed using the DRIFT spectroscopy. Methanol and carbon monoxide were used to study the catalytic activity of MgO. At relatively low temperatures, methanol dissociates to methoxide species. At higher temperatures, different oxidation products (formates and formic acid, CO and CO2) were observed to form. MgO-OX showed more oxidative properties than the MgO-TR/BR samples. Moreover, the basic and acidic sites were investigated using carbon dioxide and pyridine, respectively; the obtained results indicate a different distribution of acidic/basic sites in the different samples. (c) 2007 Published by Elsevier B.V.