05/04/2018 Offres d'emploi

Offre de thèse 2018 - LMPQ

Thèse financée à Paris Diderot portant sur le développement d'analyses TEM résolues en temps pour l'étude de la catalyse hétérogène

The Laboratoire Matériaux et Phénomènes Quantiques of Paris Diderot University
invites applications for a 3-yr PhD student position in operando transmission electron
microscopy for heterogeneous catalysis. The position starts in September 2018 and
ends in July 2021 and is proposed in the context of an ANR project (French Agency
for Research).

Thesis description
Heterogeneous catalysis is a key player in many large-scale
industrial processes and holds much promise for meeting current challenges in food,
water and energy supplies. In heterogeneous catalysis by metals, the potential of
bimetallic nanoparticles (BiM NPs) is undeniable [1]. Indeed, alloying of metal atoms
within NPs can lead to improved catalytic activity, selectivity or resistance to poisoning
as compared to monometallic NPs. Presently, the capability to design novel and more
efficient BiM catalysts is hampered by the lack of a detailed understanding of the
mechanisms of catalytic reactions, especially because particle structure and surface
composition under reaction are unknown most often.

The purpose of this thesis is to gain fundamental atomic-scale insights into the interplay
between the surface structuration and catalytic properties of heterogeneous bimetallic
catalysts in conditions as close as possible to catalytic test ones, i.e., pressure and
temperature. The structural and catalytic properties of BiM catalysts "in action" will be
characterized operando using time-resolved aberration-corrected transmission
electron microscopy imaging and spectroscopic techniques [2] coupled to mass
spectrometry (MS).

In a first step, the PhD student will focus on finalizing the development of time-resolved
operando transmission electron microscopy (TEM). In a second step, we propose to
study in operando conditions the structure of model and active Au-Cu BiM NPs
supported on titanium oxide (TiO2) and to address their catalytic performance in two
reactions of environmental and industrial interests: the oxidation of carbon monoxide
(CO) at room temperature and the selective hydrogenation of butadiene into butenes
in temperature, and at ambient pressure. To guide operando conditions, the PhD
student will also be involved in laboratory catalytic testing of Au-Cu BiM NPs using a
fixed-bed reactor under gas flow [3] under the supervision of C. Louis and L. Delannoy
at the Laboratoire de Réactivité des Surfaces (Pierre et Marie Curie University, Paris).
He/she will also work in close collaboration with theoretical scientists involved in the
ANR project to confront theory and experiments.

[1] O.G. Ellert et al., Bimetallic nanoalloys in heterogeneous catalysis of industrially important
reactions: synergetic effects and structural organization of the active components, Russian
Chemical Reviews, 83(8) 2014
[2] C. Ricolleau et al., Performances of an 80-200 kV microscope employing a cold-FEG and
an aberration-corrected objective lens, Microscopy, 62(2) 2013
[3] L. Delannoy et al., Selective hydrogenation of butadiene over TiO2 supported copper,
gold and gold-copper catalysts prepared by deposition-precipitation, Physical Chemistry
Chemical Physics, 16(48) 2014

Net salary: ~ 1400 €/monthly

Thesis requirements and qualification
The desired profile is the following: Good knowledge of materials science or solid‐state
physics (knowledge in electron optics and heterogeneous catalysis will be a major
asset). Strong motivation to perform in a multidisciplinary environment at the frontier of
physics and chemistry. Autonomy, ability to work in a team, synthetic/redaction ability
and good knowledge of French and English language are requested.

Application should include
– Cover letter in French/English motivating the candidate interest in the position.
– Names and contact information of at least one reference.
– Up-to-date CV with education history and research experience.
– Copy of university marks at the bachelor and Master levels.
to jaysen.nelayah@univ-paris-diderot.fr

For any enquiry, feel free to contact: Jaysen Nelayah (Assist. Prof, Paris Diderot
University), jaysen.nelayah@univ-paris-diderot.fr


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