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Operando Electron Microscopy Study of Cobalt‐based Fischer‐Tropsch Nanocatalysts
Author(s) -
Dembélé Kassiogé,
Bahri Mounib,
Hirlimann Charles,
Moldovan Simona,
Berliet Adrien,
Maury Sylvie,
Gay AnneSophie,
Ersen Ovidiu
Publication year - 2021
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.202001074
Subject(s) - fischer–tropsch process , cobalt , nanomaterial based catalyst , catalysis , syngas , nanoparticle , chemical engineering , materials science , transmission electron microscopy , chemistry , nanotechnology , selectivity , metallurgy , organic chemistry , engineering
Thanks to their stability and selectivity for long‐chains hydrocarbons, supported Co nanoparticles are the most commonly used catalysts in the Fischer‐Tropsch synthesis reaction. We report here on the use of in situ transmission electron microscopy (TEM) to address the real‐time evolution of cobalt‐based catalysts during their reduction under relevant industrial activation condition (10 5 Pa, 430 °C), and their operation in syngas (H 2 /CO=2, 10 5 Pa, 220 °C). To do so, we chose Co 3 O 4 −Pt nanoparticles supported on silica or alumina that can be directly compared to some industrial catalysts. By analysing the real space information contained in the TEM images, we have monitored the fragmentation of cobalt aggregates, the disappearance of cavities within the particles, their shape changes, the particle diffusion and coalescence processes, as well as the effect of the support (silica or alumina) on the behaviour of the Co phase. An easier reduction of cobalt catalysts supported on silica as compared to the same catalyst supported on alumina was also observed. During the catalyst operation under syngas, we have noticed the stability of the general shape of the particles. Simultaneously, using a residual gas analyser connected to the TEM holder, the main gas products of the Fischer‐Tropsch reaction were systematically analysed. Our findings underline the benefit of the operando TEM to study the dynamical evolution of catalysts, at the nanoparticle level, under operation conditions.