摘要
采用热丝化学气相沉积法制备了含有钽原子的石墨烯竖立片层,并将其置于含氧环境中进行退火处理,在常压环境中发生相变得到纳米金刚石,并研究退火环境中氧含量变化对纳米金刚石形成的影响.结果表明,当退火环境气压为10 Pa和50 Pa (对应氧原子百分比为1.96%和2.04%)时,退火后样品形貌与结构和未处理的石墨烯片层无异;样品100 Pa和500 Pa气压下退火后(对应氧原子百分比为2.77%和3.11%),在其中观察到了尺寸为2—4 nm的纳米金刚石,这些金刚石晶粒多分布于非晶碳中;继续升高退火环境气压则发现退火后样品被大面积氧化,石墨结构遭到严重破坏.该研究结果为纳米金刚石的制备提供了新方法.
A basic and important way to prepare diamond is to make graphite experience the phase transformation under the high-pressure high-temperature(HPHT)condition.However,this method needs stringent equipment and high investment cost.Recently,we proposed a method to prepare the diamond by phase transformation of graphite at atmospheric pressure with monodispersed Ta atoms.It is found that a phase transformation happens to H atoms under atmospheric pressure,but the role of O atoms has not been investigated.Here,we use tantalum wires as Ta source and heat the filaments to prepare vertical graphene containing Ta atoms in hot filament chemical vapor deposition(HFCVD)system.And then the vertical graphene layers are annealed in oxygen-containing environment,and nanodiamonds are obtained by phase transformation from the vertical graphene under atmospheric pressure.The results show that the sample morphologies are the same as the untreated vertical graphene’s,when the annealed ambient air pressure is at 10 Pa and 50 Pa with oxygen atom content of 1.96%and 2.04%,respectively;TEM tests reveal TaC and graphite but no diamond in these samples.Nanodiamond grains with the size range of 2-4 nm are observed in the amorphous carbon region of samples annealed at 100 Pa and 500 Pa air pressure with oxygen atom content increasing to 2.77%and 3.11%,respectively,indicating that oxidation facilitates the phase change from Ta-containing vertical graphene to diamond at atmospheric pressure.When the air pressure of the annealing environment rises to 1000 Pa with the oxygen atom content of 3.54%,the sample is extensively oxidized and the graphite structure is severely damaged,which means that a large number of oxygen atoms tend to disrupt the graphite structure rather than promote the phase change into diamond.These results supply a way to prepare nanodiamond and show the effect of O atoms in the graphite phase transition at atmospheric pressure.
作者
朱奕衡
朱志光
陈成克
蒋梅燕
李晓
鲁少华
胡晓君
Zhu Yi-Heng;Zhu Zhi-Guang;Chen Cheng-Ke;Jiang Mei-Yan;Li Xiao;Lu Shao-Hua;Hu Xiao-Jun(College of Materials Science and Engineering,Zhejiang University of Technology,Hangzhou 310014,China;Moganshan Diamond Research Center,Huzhou 313200,China;Diamond Joint Research Center for Zhejiang University of Technology and Tanghe Scientific&Technology Company,Huzhou 313200,China)
出处
《物理学报》
SCIE
EI
CSCD
北大核心
2024年第2期293-301,共9页
Acta Physica Sinica
基金
国家自然科学基金联合重点项目(批准号:U1809210)、国家自然科学基金(批准号:52102052,11504325,52002351,50972129,50602039)
国家国际科技合作项目(批准号:2014DFR51160)
国家重点研发计划(批准号:2016YFE0133200)
浙江省自然科学基金(批准号:LQ15A040004,LY18E020013,LGC21E020001)
浙江省重点研发计划国际科技合作“一带一路”专项(批准号:2018C04021)资助的课题。
关键词
石墨烯
纳米金刚石
常压相变
graphene
nanodiamond
phase transition under ordinary pressure
