单壁碳纳米管在单金属层状双氢氧化物上的手性选择性生长  

Chirality-selective growth of single-walled carbon nanotubes from layered double hydroxide supported monometallic catalysts

作　　者：李雅涵 郝树兰 徐宁宁 高 秦潇藩 郗心砚 何宁 何茂帅 Yahan Li;Shulan Hao;Ningning Xu;Yan Gao;Xiaofan Qin;Xinyan Chi;Ning He;Maoshuai He(College of Chemistry and Molecular Engineering,Qingdao University of Science and Technology,Qingdao 266042,China;College of Chinesisch-Deutsche Fakultat für Ingenieurwissenschaften,Qingdao University of Science and Technology,Qingdao 266042,China)

机构地区：[1]青岛科技大学化学与分子工程学院,青岛266042 [2]青岛科技大学中德工程学院,青岛266042

出　　处：《科学通报》2024年第16期2288-2297,共10页Chinese Science Bulletin

基　　金：国家自然科学基金(51972184);山东省自然科学基金(ZR2019ZD49)资助。

摘　　要：制备具有窄手性分布的单壁碳纳米管(single-walled carbon nanotubes,SWNTs)粉体是实现其潜在应用的基础和前提.本文设计并开发了分别含有单金属钴(Co)和镍(Ni)的层状双氢氧化物(layered double hydroxides,LDHs)催化剂前驱体,利用一氧化碳作为碳源,系统研究了碳纳米管在不同温度下的化学气相沉积合成.在反应气氛下,煅烧后的Co/Mg/Al LDHs催化剂在600℃即可活化,进而选择性生长出小直径、富集(6,5)手性的SWNTs产物.而煅烧后的Ni/Mg/Al LDHs催化剂在600℃的低温下无法活化生长出SWNTs.尽管进一步提升反应温度至700℃能够活化催化剂,但是由于还原形成的Ni纳米粒子在较高反应温度下容易团聚,所得到的SWNTs的手性分布相对较宽.这项工作不仅实现了窄手性分布SWNTs在单金属LDHs上的催化生长,同时还有助于加深对催化剂活化及SWNTs生长机制的理解.Single-walled carbon nanotubes(SWNTs)display exceptional electrical and optical properties,closely tied to chiral indices(n,m)that define their structures.To fully exploit these distinctive characteristics and push forward their applications,there is a significant demand for preparing SWNTs with specific chirality and controllable properties.In order to facilitate the separation of single-chirality SWNTs by postgrowth approaches,it is essential to synthesize bulk SWNTs with a narrow chirality distribution.This can be achieved through cost-effective techniques like chemical vapor deposition(CVD)by using solid supported catalysts,which is characterized by a well dispersed active catalyst component on a mesoporous support with a high surface area.However,it is important to address the challenge of nonuniform impregnation during the catalyst preparation process.This issue can lead to the formation of nanoparticles with varying diameters,which hinders the growth of uniform SWNTs.To overcome this hurdle,the development of novel supported catalysts specifically designed for chirality-selective SWNT synthesis becomes imperative.Hereby,we prepared two types of layered double hydroxides(LDHs),which respectively consist of Co/Mg/Al and Ni/Mg/Al,as the catalyst precursors for catalytic growth of carbon nanotubes by CVD.As a structured catalyst,LDHs consist of positively charged brucite-like layers,which are built from metal hydroxide octahedra with hydroxyl groups(OH-)at the corners.Through the process of calcination,the LDHs undergo transformations into mixed oxides.Importantly,the resulting mixed oxides retain a plate-like morphology and uniformly distributed metal cations.Upon reduction under the reaction temperature,metal cations,like Co2+and Ni2+,could be reduced and migrate into uniform metal clusters anchored by the underlying host materials for subsequent growth of carbon nanotubes.In this work,we systematically investigated the catalytic performances of calcined LDHs in which the respective catalyst components are C

关 键 词：单壁碳纳米管 手性选择性生长 层状双氢氧化物 一氧化碳 化学气相沉积 

分 类 号：TB383.1[一般工业技术—材料科学与工程] TQ127.11[化学工程—无机化工]