Bakos László Péter, Justh Nóra, Moura da Silva Bezerra da Costa Ulisses Carlo, László Krisztina, Lábár János László, Igricz Tamás, Varga-Josepovits Katalin, Pasierb Pawel, Färm Elina, Ritala Mikko, Leskelä Markku, Szilágyi Imre Miklós
Department of Inorganic and Analytical Chemistry, Budapest University of Technology and Economics, Szent Gellért tér 4., H-1111 Budapest, Hungary.
Department of Physical Chemistry and Materials Science, Budapest University of Technology and Economics, P.O. Box 92, H-1521 Budapest, Hungary.
Nanomaterials (Basel). 2020 Jan 31;10(2):252. doi: 10.3390/nano10020252.
TiO and ZnO single and multilayers were deposited on hydroxyl functionalized multi-walled carbon nanotubes using atomic layer deposition. The bare carbon nanotubes and the resulting heterostructures were characterized by TG/DTA, Raman, XRD, SEM-EDX, XPS, TEM-EELS-SAED and low temperature nitrogen adsorption techniques, and their photocatalytic and gas sensing activities were also studied. The carbon nanotubes (CNTs) were uniformly covered with anatase TiO and wurtzite ZnO layers and with their combinations. In the photocatalytic degradation of methyl orange, the most beneficial structures are those where ZnO is the external layer, both in the case of single and double oxide layer covered CNTs (CNT-ZnO and CNT-TiO-ZnO). The samples with multilayer oxides (CNT-ZnO-TiO and CNT-TiO-ZnO) have lower catalytic activity due to their larger average densities, and consequently lower surface areas, compared to single oxide layer coated CNTs (CNT-ZnO and CNT-TiO). In contrast, in gas sensing it is advantageous to have TiO as the outer layer. Since ZnO has higher conductivity, its gas sensing signals are lower when reacting with NH gas. The double oxide layer samples have higher resistivity, and hence a larger gas sensing response than their single oxide layer counterparts.
采用原子层沉积法在羟基官能化的多壁碳纳米管上沉积了TiO和ZnO单层及多层膜。通过热重/差热分析（TG/DTA）、拉曼光谱、X射线衍射（XRD）、扫描电子显微镜-能谱分析（SEM-EDX）、X射线光电子能谱（XPS）、透射电子显微镜-电子能量损失谱-选区电子衍射（TEM-EELS-SAED）和低温氮吸附技术对裸碳纳米管及其形成的异质结构进行了表征，并研究了它们的光催化和气体传感活性。碳纳米管（CNTs）被锐钛矿型TiO和纤锌矿型ZnO层及其组合均匀覆盖。在甲基橙的光催化降解中，最有利的结构是ZnO为外层的结构，无论是单层氧化物覆盖的碳纳米管（CNT-ZnO）还是双层氧化物覆盖的碳纳米管（CNT-TiO-ZnO）都是如此。与单层氧化物涂层的碳纳米管（CNT-ZnO和CNT-TiO）相比，多层氧化物样品（CNT-ZnO-TiO和CNT-TiO-ZnO）由于其平均密度较大，因而表面积较小，催化活性较低。相反，在气体传感方面，以TiO作为外层是有利的。由于ZnO具有较高的电导率，其与NH气体反应时的气敏信号较低。双层氧化物层样品具有较高的电阻率，因此比单层氧化物层样品具有更大的气敏响应。
