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Johansson, D. (2015) Nanoplasmonic Sensing of Transition Metal Catalyst Nanoparticle Oxidation States. Göteborg : Chalmers University of Technology
BibTeX
@mastersthesis{
Johansson2015,
author={Johansson, David},
title={Nanoplasmonic Sensing of Transition Metal Catalyst Nanoparticle Oxidation States},
abstract={Abstract
Catalysis is an important and key part of many processes both in fundamental
research and in the applied chemical industry. The oxidation and reduction of tran-
sition metal catalysts are common reactions that affect the catalytic performance
of the corresponding nanoparticles. Hence it is very important to understand the
role of the oxidation state in a catalytic process, as well as to control it in order to
maximize catalyst performance towards the formation of the desired product(s).
In this study copper and cobalt nanoparticle catalysts of sizes 67-190 nm were stud-
ied
in situ
with direct and indirect plasmonic sensing in temperature-programmed
oxidation and reduction experiments. The experimental study proved, together
with computational simulations with the Modified Long Wavelength Approxima-
tion, that the oxidation of copper yields a distinct change of the optical spectrum of
the nanoparticles, and their exposure to 2 vol% O
2
in 200
◦
C will mainly form Cu
2
O.
The oxidation and reduction process of copper was also found to be reversible, and
the temperature for the two processes was found to slightly decrease over the reac-
tion cycles, due to structural changes of the particles.
The outcome of the temperature-programmed oxidation and reduction experiments
of cobalt nanoparticles was in several ways different from the copper ones. The
most significant difference was that a broad dramatic change in extinction during
the reduction process for the temperatures around 310-360
◦
C was found. It was
concluded that the effect was a combinatory result of a martensitic transformation,
which simultaneously induced an increased oxidation rate of the cobalt oxides Co2O3 or CoO, as well as gives rise to a decrease of the conductivity.
},
publisher={Institutionen för teknisk fysik, Chalmers tekniska högskola},
place={Göteborg},
year={2015},
keywords={Localized plasmonic resonance, heterogeneous catalysis, nanoparticle},
note={77},
}
RefWorks
RT Generic
SR Electronic
ID 220177
A1 Johansson, David
T1 Nanoplasmonic Sensing of Transition Metal Catalyst Nanoparticle Oxidation States
YR 2015
AB Abstract
Catalysis is an important and key part of many processes both in fundamental
research and in the applied chemical industry. The oxidation and reduction of tran-
sition metal catalysts are common reactions that affect the catalytic performance
of the corresponding nanoparticles. Hence it is very important to understand the
role of the oxidation state in a catalytic process, as well as to control it in order to
maximize catalyst performance towards the formation of the desired product(s).
In this study copper and cobalt nanoparticle catalysts of sizes 67-190 nm were stud-
ied
in situ
with direct and indirect plasmonic sensing in temperature-programmed
oxidation and reduction experiments. The experimental study proved, together
with computational simulations with the Modified Long Wavelength Approxima-
tion, that the oxidation of copper yields a distinct change of the optical spectrum of
the nanoparticles, and their exposure to 2 vol% O
2
in 200
◦
C will mainly form Cu
2
O.
The oxidation and reduction process of copper was also found to be reversible, and
the temperature for the two processes was found to slightly decrease over the reac-
tion cycles, due to structural changes of the particles.
The outcome of the temperature-programmed oxidation and reduction experiments
of cobalt nanoparticles was in several ways different from the copper ones. The
most significant difference was that a broad dramatic change in extinction during
the reduction process for the temperatures around 310-360
◦
C was found. It was
concluded that the effect was a combinatory result of a martensitic transformation,
which simultaneously induced an increased oxidation rate of the cobalt oxides Co2O3 or CoO, as well as gives rise to a decrease of the conductivity.
PB Institutionen för teknisk fysik, Chalmers tekniska högskola,
LA eng
LK http://publications.lib.chalmers.se/records/fulltext/220177/220177.pdf
OL 30