基于石墨烯竖立片层常压相变制备纳米金刚石
Preparation of nanodiamonds based on phase transformation of vertical sheet under atmospheric pressure
摘要
Abstract
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.关键词
石墨烯/纳米金刚石/常压相变Key words
graphene/nanodiamond/phase transition under ordinary pressure引用本文复制引用
朱奕衡,朱志光,陈成克,蒋梅燕,李晓,鲁少华,胡晓君..基于石墨烯竖立片层常压相变制备纳米金刚石[J].物理学报,2024,73(2):293-301,9.基金项目
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)和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. Project supported by the Key Project of National Natural Science Foundation of China(Grant No.U1809210),the National Natural Science Foundation of China(Grant Nos.52102052,11504325,52002351,50972129,50602039),the International Science and Technology Cooperation Program of China(Grant No.2014DFR51160),the National Key Research and Development Program of China(Grant No.2016YFE0133200),the Natural Science Foundation of Zhejiang Province,China(Grant Nos.LQ15A040004,LY18E020013,LGC21E020001),and the Key Research and Development Program of Zhejiang Province,China(Grant No.2018C04021). （批准号:U1809210）
