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Onion‐Like Graphene Carbon Nanospheres as Stable Catalysts for Carbon Monoxide and Methane Chlorination
Author(s) -
Centi Gabriele,
Barbera Katia,
Perathoner Siglinda,
Gupta Navneet K.,
Ember Erika E.,
Lercher Johannes A.
Publication year - 2015
Publication title -
chemcatchem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.497
H-Index - 106
eISSN - 1867-3899
pISSN - 1867-3880
DOI - 10.1002/cctc.201500662
Subject(s) - chemisorption , graphene , reactivity (psychology) , catalysis , x ray photoelectron spectroscopy , raman spectroscopy , carbon fibers , fullerene , chemistry , carbon monoxide , methane , photochemistry , materials science , inorganic chemistry , chemical engineering , nanotechnology , organic chemistry , medicine , alternative medicine , pathology , composite number , engineering , composite material , physics , optics
Thermal treatment induces a modification in the nanostructure of carbon nanospheres that generates ordered hemi‐fullerene‐type graphene shells arranged in a concentric onion‐type structure. The catalytic reactivity of these structures is studied in comparison with that of the parent carbon material. The change in the surface reactivity induced by the transformation of the nanostructure, characterized by TEM, XRD, X‐ray photoelectron spectroscopy (XPS), Raman, and porosity measurements, is investigated by multipulses of Cl 2 in inert gas or in the presence of CH 4 or CO. The strained CC bonds (sp 2 ‐type) in the hemi‐fullerene‐type graphene shells induce unusually strong, but reversible, chemisorption of Cl 2 in molecular form. The active species in CH 4 and CO chlorination is probably in the radical‐like form. Highly strained CC bonds in the parent carbon materials react irreversibly with Cl 2 , inhibiting further reaction with CO. In addition, the higher presence of sp 3 ‐type defect sites promotes the formation of HCl with deactivation of the reactive CC sites. The nano‐ordering of the hemi‐fullerene‐type graphene thus reduces the presence of defects and transforms strained CC bonds, resulting in irreversible chemisorption of Cl 2 to catalytic sites able to perform selective chlorination.