When carbon-containing species are involved in reactions catalyzed by transition metals at high temperature,the diffusion of carbon on or in catalysts dramatically influences the catalytic performance.Acquiring inform...When carbon-containing species are involved in reactions catalyzed by transition metals at high temperature,the diffusion of carbon on or in catalysts dramatically influences the catalytic performance.Acquiring information on the carbon-diffusioninvolved evolution of catalysts at the atomic level is crucial for understanding the reaction mechanism yet also challenging.For the chemical vapor deposition process of single-walled carbon nanotubes(SWCNTs),we recorded in situ the catalyst state(solid and molten)composition as well as near-surface structural and chemical evolution at the cobalt catalyst-tube interface with carbon permeation using aberration-corrected environmental transmission electron microscopy and synchrotron X-ray absorption spectroscopy.The nucleation of SWCNTs was linked with an alternating dissolving and precipitating cycle of carbon in catalysts close to the nucleation site.Understanding the dynamics of carbon atoms in catalysts brings deeper insight into the growth mechanism of SWCNTs and facilitates inferring mechanisms of other reactions.The methodologies developed here will find broad applications in studying catalytic and other processes.展开更多
基金supported by National Key Research and Development Program of China(nos.2016YFA0201904 and 2018YFA0703700)National Natural Science Foundation of China(NSFC)(nos.21631002,12034002,and 51971025)+7 种基金Beijing National Laboratory for Molecular Sciences(no.BNLMS-CXTD202001)Shenzhen Basic Research Project(no.JCYJ20170817113121505)Shenzhen KQTD Project(no.KQTD20180411143400981)Fundamental Research Funds for the Central Universities(no.FRFBD-18-004A)J.H.acknowledges the Science and Technology Innovation Committee Foundation of Shenzhen(nos.KQTD2016022619565991 and ZDSYS20141118160434515)F.Y.was supported in part by NSFC(no.52002165)Beijing National Laboratory for Molecular Science(no.BNLMS202013)Guangdong Provincial Natural Science Foundation,Innovation Project for Guangdong Provincial Department of Education(no.2019KTSCX155).
文摘When carbon-containing species are involved in reactions catalyzed by transition metals at high temperature,the diffusion of carbon on or in catalysts dramatically influences the catalytic performance.Acquiring information on the carbon-diffusioninvolved evolution of catalysts at the atomic level is crucial for understanding the reaction mechanism yet also challenging.For the chemical vapor deposition process of single-walled carbon nanotubes(SWCNTs),we recorded in situ the catalyst state(solid and molten)composition as well as near-surface structural and chemical evolution at the cobalt catalyst-tube interface with carbon permeation using aberration-corrected environmental transmission electron microscopy and synchrotron X-ray absorption spectroscopy.The nucleation of SWCNTs was linked with an alternating dissolving and precipitating cycle of carbon in catalysts close to the nucleation site.Understanding the dynamics of carbon atoms in catalysts brings deeper insight into the growth mechanism of SWCNTs and facilitates inferring mechanisms of other reactions.The methodologies developed here will find broad applications in studying catalytic and other processes.
