{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,3,10]],"date-time":"2026-03-10T03:16:43Z","timestamp":1773112603828,"version":"3.50.1"},"reference-count":39,"publisher":"MDPI AG","issue":"5","license":[{"start":{"date-parts":[[2020,4,25]],"date-time":"2020-04-25T00:00:00Z","timestamp":1587772800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Catalysts"],"abstract":"<jats:p>This Note aims at clarifying the alternative mechanisms of carbon formation from gases at temperatures above 550 \u00b0C. Both the growth of carbon nanotubes (CNTs) by a hybrid route, and of graphene layers deposition by a pyrolytic route are analyzed: the transition had no influence in apparent kinetics, but the carbon structure was totally different. The transition temperature from hybrid to pyrolytic growth varies with the gas pressure: higher temperature transition was possible using lower active gas pressures. The rate-determining step concept is essential to understanding the behavior. In catalytic and hybrid carbon formation, the slower step controls and determines kinetics. In the pyrolytic region, the faster step dominates, and carbon bulk diffusion is blocked: layers of graphene cover the external catalyst surface. It is easier to optimize CNTs growth (rate, shape, properties) knowing the details of the alternative mechanisms operating.<\/jats:p>","DOI":"10.3390\/catal10050465","type":"journal-article","created":{"date-parts":[[2020,4,27]],"date-time":"2020-04-27T04:15:29Z","timestamp":1587960929000},"page":"465","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":11,"title":["Carbon Formation at High Temperatures (550\u20131400 \u00b0C): Kinetics, Alternative Mechanisms and Growth Modes"],"prefix":"10.3390","volume":"10","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-2618-0372","authenticated-orcid":false,"given":"Lu\u00eds Sousa","family":"Lobo","sequence":"first","affiliation":[{"name":"LAQV-REQUIMTE, Department of Chemistry, NOVA School of Science and Technology, Universidade NOVA de Lisboa, 2829-516 Caparica, Portugal"}]},{"given":"S\u00f3nia A. C.","family":"Carabineiro","sequence":"additional","affiliation":[{"name":"LAQV-REQUIMTE, Department of Chemistry, NOVA School of Science and Technology, Universidade NOVA de Lisboa, 2829-516 Caparica, Portugal"}]}],"member":"1968","published-online":{"date-parts":[[2020,4,25]]},"reference":[{"key":"ref_1","first-page":"265","article-title":"The Formation of Carbon from Gases","volume":"Volume 1","author":"Palmer","year":"1965","journal-title":"Chemistry and Physics of Carbon"},{"key":"ref_2","first-page":"173","article-title":"Deposition of Pyrolytic Carbon in Porous Solids","volume":"Volume 9","author":"Kotlensky","year":"1973","journal-title":"Chemistry and Physics of Carbon"},{"key":"ref_3","unstructured":"Bokros, J.C. (1969). Deposition, Structure and Properties of Pyrolytic Carbons. Chemistry and Physics of Carbon, Dekker."},{"key":"ref_4","unstructured":"Barrer, R.M. (1941). Diffusion in and through Solids, Cambridge Univ. Press."},{"key":"ref_5","first-page":"133","article-title":"Gas Reactions of Carbon","volume":"Volume 11","author":"Walker","year":"1959","journal-title":"Advances in Catalysis"},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"1044","DOI":"10.1021\/j100824a501","article-title":"Some kinetics of the carbonization of benzene, acetylene and diacetylene at 1200 degree","volume":"65","author":"Slysh","year":"1961","journal-title":"J. Phys. Chem."},{"key":"ref_7","first-page":"444","article-title":"Deposition, Structure and Properties of Pyrolytic Carbons","volume":"224","author":"Ford","year":"1967","journal-title":"Engineer"},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"559","DOI":"10.1007\/BF00549741","article-title":"Effect of Substrate Structure on Deposition of Evaporated Carbon","volume":"3","author":"Fischback","year":"1968","journal-title":"J. Mater. Sci."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1016\/0008-6223(69)90002-5","article-title":"Growth of single-crystal graphite by pyrolysis of acetylene over metals","volume":"7","author":"Presland","year":"1969","journal-title":"Carbon"},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"54","DOI":"10.1021\/ie50730a005","article-title":"Survey of Recent Methane Pyrolysis Literature","volume":"62","author":"Khan","year":"1970","journal-title":"Ind. Eng. Chem."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"435","DOI":"10.1016\/0008-6223(70)90003-5","article-title":"Formation of Carbon Fibers from Acetylene","volume":"8","author":"Tesner","year":"1970","journal-title":"Carbon"},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"15","DOI":"10.1038\/physci234015a0","article-title":"Complex temperature dependencies of the rate of carbon deposition on nickel","volume":"234","author":"Lobo","year":"1971","journal-title":"Nat. Phys. Sci."},{"key":"ref_13","unstructured":"Lobo, L.S., and Trimm, D.L. (1972). Studies of Carbon Formation on Metals Using a Vacuum Microbalance. Progress in Vacuum Microbalance Techniques, Heyden & Son."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"51","DOI":"10.1016\/0021-9517(72)90032-2","article-title":"Nucleation and Growth of C Deposits from Ni Catalyzed Decomposition of C2H2","volume":"26","author":"Baker","year":"1972","journal-title":"J. Catal."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"155","DOI":"10.1016\/0021-9517(77)90087-2","article-title":"Mechanism of Carbon Formation on Nickel-Containing Catalysts","volume":"48","author":"Nielsen","year":"1977","journal-title":"J. Catal."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"56","DOI":"10.1038\/354056a0","article-title":"Helical microtubules of graphitic carbon","volume":"354","author":"Iijima","year":"1991","journal-title":"Nature"},{"key":"ref_17","unstructured":"Saito, R., Dresselhause, G., and Dresselhause, M.S. (1998). Physical Properties of Carbon Nanotubes, Imperial College Press."},{"key":"ref_18","doi-asserted-by":"crossref","unstructured":"Harris, P.J.F. (2009). Carbon Nanotube Science, Cambridge University Press.","DOI":"10.1017\/CBO9780511609701"},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"3376","DOI":"10.1016\/j.carbon.2012.03.024","article-title":"The role of the hydrocarbon source on the growth of carbon materials","volume":"50","author":"Shaikjee","year":"2012","journal-title":"Carbon"},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1016\/j.jaap.2014.05.022","article-title":"Hydrocarbon pyrolysis with a methane focus: A review on the catalytic effect and the coke production","volume":"108","author":"Fau","year":"2014","journal-title":"J. Anal. Appl. Pyrol."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"221","DOI":"10.1016\/j.rser.2014.12.025","article-title":"Production of greenhouse gas free hydrogen by thermocatalytic decomposition of methane\u2014A review","volume":"44","author":"Ashik","year":"2015","journal-title":"Renew. Sustain. Energy Rev."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"743","DOI":"10.1016\/j.rser.2017.03.088","article-title":"A review on CH4 transformation to H2 and nanocarbon","volume":"76","author":"Ashik","year":"2017","journal-title":"Renew. Sustain. Energy Rev."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"36","DOI":"10.1039\/C7QM00427C","article-title":"Towards monochiral carbon nanotubes: A review of progress in the sorting of single-walled CNTs","volume":"2","author":"Janas","year":"2018","journal-title":"Mater. Chem. Front."},{"key":"ref_24","doi-asserted-by":"crossref","unstructured":"Lobo, L.S. (2019). Mechanism of Catalytic CNTs Growth in 400\u2013650 \u00b0C Range: Explaining Volcano Shape Arrhenius Plot and Catalytic Synergism Using both Pt (or Pd) and Ni, Co or Fe. C J. Carbon Res., 5.","DOI":"10.3390\/c5030042"},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"393","DOI":"10.1007\/s11144-016-0993-x","article-title":"Catalytic carbon formation: Clarifying the alternative kinetic routes and defining a kinetic linearity for sustained growth concept","volume":"118","author":"Lobo","year":"2016","journal-title":"Reac. Kinet. Mech. Cat."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"411","DOI":"10.1016\/j.carbon.2016.12.005","article-title":"Nucleation and growth of carbon nanotubes and nanofibers: Mechanism and catalytic geometry control","volume":"114","author":"Lobo","year":"2017","journal-title":"Carbon"},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"103","DOI":"10.1016\/j.apcata.2008.06.028","article-title":"Catalytic decomposition of methane on Raney-type catalysts","volume":"348","author":"Cunha","year":"2008","journal-title":"Appl. Catal. A"},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"9795","DOI":"10.1016\/j.ijhydene.2009.12.071","article-title":"H2 production via CH4 decomposition on Raney-type catalysts","volume":"35","author":"Figueiredo","year":"2010","journal-title":"Int. J. Hydrogen Energy"},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"50","DOI":"10.1016\/j.catcom.2013.07.035","article-title":"Ce-Doped La2O3 based catalyst for the oxidative coupling of methane","volume":"42","author":"Ferreira","year":"2013","journal-title":"Catal. Commun."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"4104","DOI":"10.1016\/j.ijhydene.2008.05.072","article-title":"Study of the deactivation mechanism of carbon blacks used in methane decomposition","volume":"33","author":"Pinilla","year":"2008","journal-title":"Int. J. Hydrogen Energy"},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"539","DOI":"10.1016\/S0008-6223(02)00362-7","article-title":"Synthesis of carbon nanotubes over Fe catalyst on aluminium and suggested growth mechanism","volume":"41","author":"Emmenegger","year":"2003","journal-title":"Carbon"},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"234","DOI":"10.1016\/0008-6223(95)92803-M","article-title":"Effect of H2 on the morphology of C deposited from the catalytic disproportionation of CO","volume":"33","author":"Herreyre","year":"1995","journal-title":"Carbon"},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"128","DOI":"10.1007\/s100190050075","article-title":"Synthesis of MW and SW nanotubes, aligned-nanotube bundles and nanorods by employing organometallic precursors","volume":"2","author":"Rao","year":"1998","journal-title":"Mat. Res. Innovat."},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"11","DOI":"10.1016\/j.mseb.2018.03.001","article-title":"CNTs\u2019 array growth using the floting catalyst-CVD method over different substrates and H2 supply","volume":"231","author":"Guellati","year":"2018","journal-title":"Mater. Sci. Eng. B"},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"20973","DOI":"10.1021\/jp0636571","article-title":"Thermal decomposition of Ferrocene as a Method for Production of SWCNTs without Additional Carbon Sources","volume":"110","author":"Barreiro","year":"2006","journal-title":"J. Phys. Chem. B"},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"16684","DOI":"10.1021\/jp051531i","article-title":"Molecular Beam-Controlled Nucleation and Growth of Vertically Aligned SWCNTs arrays","volume":"109","author":"Eres","year":"2005","journal-title":"J. Phys. Chem. B"},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"217","DOI":"10.1016\/j.cattod.2010.03.065","article-title":"Kinetics of CNTs growth on a Ni-Mg-Al catalyst by CCVD of methane: Influence of catalyst deactivation","volume":"154","author":"Latorre","year":"2010","journal-title":"Catal. Today"},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"2003","DOI":"10.1016\/S0008-6223(00)00049-X","article-title":"In situ study of CNT formation by C2H2 decomposition on an iron-based catalyst","volume":"38","author":"Valiente","year":"2000","journal-title":"Carbon"},{"key":"ref_39","doi-asserted-by":"crossref","unstructured":"Shi, Y., Wang, Y., Ren, Y., and Wan, Y. (2020). Effect of Gas Atmosphere in the Heating Stage on Limiting Nucleation of Graphene on Cu Foils by Low Pressure CVD. Cryst. Res. Technol.","DOI":"10.1002\/crat.201900181"}],"container-title":["Catalysts"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2073-4344\/10\/5\/465\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,13]],"date-time":"2025-10-13T14:33:27Z","timestamp":1760366007000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2073-4344\/10\/5\/465"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2020,4,25]]},"references-count":39,"journal-issue":{"issue":"5","published-online":{"date-parts":[[2020,5]]}},"alternative-id":["catal10050465"],"URL":"https:\/\/doi.org\/10.3390\/catal10050465","relation":{},"ISSN":["2073-4344"],"issn-type":[{"value":"2073-4344","type":"electronic"}],"subject":[],"published":{"date-parts":[[2020,4,25]]}}}