Template-free formation of oriented oxide nanowalls <i>via</i> topotactic-like pseudomorphic transformation: [110]-MgO(111) nanowall arrays
Template-free formation of oriented oxide nanowalls <i>via</i> topotactic-like pseudomorphic transformation: [110]-MgO(111) nanowall arrays
复制标题
<i>通过</i>类拓扑假晶转变无模板形成定向氧化物纳米墙：[110]-MgO(111)纳米墙阵列
DOI：
10.1039/d2ma00493c
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发表时间：
2022
影响因子：
5
通讯作者：
Izaki Masanobu
中科院分区：
文献类型：
--
作者：
Shinagawa Tsutomu;Izaki Masanobu
在不使用模板的情况下，在衬底上形成具有排列的生长方向和排列的壁晶体平面的氧化物纳米壁阵列是一个挑战。本文采用无模板自发方法：电沉积氢氧化镁（Mg(OH)2）及其拓扑样伪晶转化（TPT）制备了具有[110]生长方向和（111）壁面的定向氧化镁（MgO）纳米壁（NW）阵列。以Mg(NO3)2水溶液为原料，采用简单电化学沉积方法在导电衬底上制备了定向的Mg(OH)2 NWs，并利用扫描电镜、x射线衍射、傅里叶变换红外光谱和拉曼光谱对其进行了表征。得到的Mg(OH)2是一个垂直的纳米壁阵列结构（~ 660 nm高，20-40 nm厚），彼此相交，具有[110]生长方向和（0001）壁面。NWs的尺寸可以通过电沉积时间和沉积电流密度来控制。在500℃和800℃的空气中对[110]-Mg(OH)2(0001) NW阵列进行热处理，通过TPT工艺形成[110]-MgO(111) NW阵列。利用x射线光电子显微镜和红外光谱对NW表面的化学状态进行了分析，结果表明，与800°C加热的Mg(OH)2 NWs和MgO NWs相比，500°C加热的MgO NWs具有更好的CO2吸附性能。
Oxide nanowall arrays having aligned growth orientation and aligned wall crystal planes are a challenge to form on substrates without the use of templates. Here, oriented magnesium oxide (MgO) nanowall (NW) arrays with a [110] growth direction and (111) wall surfaces are prepared using a template-free spontaneous route: electrodeposition of magnesium hydroxide (Mg(OH)2) and its topotactic-like pseudomorphic transformation (TPT). Oriented Mg(OH)2 NWs were prepared on a conductive substrate using simple electrochemical deposition from a Mg(NO3)2 aqueous solution, and were characterized using scanning electron microscopy, X-ray diffraction, Fourier-transform infrared (FTIR) spectroscopy and Raman spectroscopy. The obtained Mg(OH)2 is a vertical nanowall array structure (∼660 nm height and 20–40 nm thickness) intersecting each other, with a [110] growth orientation and a (0001) wall surface. The size of NWs can be controlled by electrodeposition time and deposition current density. Heat treatment of the [110]-Mg(OH)2(0001) NW arrays at 500 °C and 800 °C in air led to the formation of [110]-MgO(111) NW arrays via the TPT process. The chemical state analysis of NW surfaces using X-ray photoelectron microscopy and FTIR spectroscopy revealed that MgO NWs heated at 500 °C exhibit a superior CO2 adsorption property compared to the Mg(OH)2 NWs and MgO NWs heated at 800 °C.