Publications by Vasiliki Tileli

Interior Morphology and Pore Structure in High Surface Area Carbon Catalyst Supports

Vasiliki Tileli, Robin Pierre Alain Girod

In proton exchange membrane fuel cells, the interior porosity of the standard high surface area carbon (HSC) supports anchors and shields catalysts, offering benefits in performance and durability. Yet, these carbons also add mass transport resistance. Thi ...

WILEY-V C H VERLAG GMBH2025

On Tortuosity and Water Management in Hydrophobic and Hydrophilic Microporous Layers with Different Carbon Structures

Vasiliki Tileli, Michele Bozzetti

To improve mass transport limitations in proton exchange membrane fuel cells (PEMFCs), a detailed analysis of the gas diffusion layer structure can aid to understand the transport processes of oxygen to the catalyst layer and the liquid water removal mecha ...

ELECTROCHEMICAL SOC INC2025

Chemical Interactions at the Interface of Au on Bi2Se3 Topological Insulator

Vasiliki Tileli

This study explores the intricate chemical processes at the interface between the topological insulator Bi2Se3 and deposited Au. The study mainly focused on room-temperature interactions that can cause the aging of, e.g., gold contacts on electronic device ...

2024

Quasi-operando Transmission Electron Microscopy Diagnostics for Electrocatalytic Processes in Liquids

Vasiliki Tileli

It is of great interest to the energy community to understand how the mechano-physico-chemical phenomena that eventually lead to device degradation are related to the startup, operation, and shutdown phases. For electrocatalytic systems operating in liquid ...

Swiss Chemical Soc2024

Graphene Electrode for Studying CO2 Electroreduction Nanocatalysts under Realistic Conditions in Microcells

Vasiliki Tileli, Tzu-Hsien Shen

The ability to resolve the dynamic evolution of electrocatalytically induced processes with electrochemical liquid-phase electron microscopy (EM) is limited by the microcell configuration. Herein, a free-standing tri-layer graphene is integrated as a membr ...

Wiley-V C H Verlag Gmbh2024

Up-Scaled Preparation of Pt-Ni Aerogel Catalyst Layers for Polymer Electrolyte Fuel Cell Cathodes

Vasiliki Tileli, Michele Bozzetti

High activity and durability are two key requirements for the successful development of Pt-based ORR catalyst layers for polymer electrolyte fuel cell (PEFC) cathodes. Unsupported Pt-Ni aerogels consisting of an interconnected nanoparticle network have bee ...

2024

Catalyst Aggregate Size Effect on the Mass Transport Properties of Non-Noble Metal Catalyst Layers for PEMFC Cathodes

Yen-Chun Chen, Vasiliki Tileli, Robin Pierre Alain Girod, Michele Bozzetti, Secil Unsal

Non-noble metal catalysts (NNMCs) are regarded as a promising alternative to the costly Pt-based materials required to catalyze the oxygen reduction reaction (ORR) in proton exchange membrane fuel cell (PEMFC) cathodes. However, the large diversity of NNMC ...

ELECTROCHEMICAL SOC INC2023

Insights into Electrocatalyst Transformations Studied in Real Time with Electrochemical Liquid-Phase Transmission Electron Microscopy

Vasiliki Tileli, Tzu-Hsien Shen, Robin Pierre Alain Girod

The value of operando and in situ characterization methodologies for understanding electrochemical systems under operation can be inferred from the upsurge of studies that have reported mechanistic insights into electrocatalytic processes based on such mea ...

Amer Chemical Soc2023

Three-dimensional nanoimaging of fuel cell catalyst layers

Vasiliki Tileli, Robin Pierre Alain Girod, Timon Lazaridis

Catalyst layers in proton exchange membrane fuel cells consist of platinum-group-metal nanocatalysts supported on carbon aggregates, forming a porous structure through which an ionomer network percolates. The local structural character of these heterogeneo ...

NATURE PORTFOLIO2023

Elucidating the Mechanism of Fe Incorporation in In Situ Synthesized Co-Fe Oxygen-Evolving Nanocatalysts

Thi Ha My Pham, Andreas Züttel, Vasiliki Tileli, Tzu-Hsien Shen, Youngdon Ko, Liping Zhong

Ni- and Co-based catalysts with added Fe demonstrate promising activity in the oxygen evolution reaction (OER) during alkaline water electrolysis, with the presence of Fe in a certain quantity being crucial for their enhanced performance. The mode of incor ...

Amer Chemical Soc2023

Decoupling the Contributions of Different Instability Mechanisms to the PEMFC Performance Decay of Non-noble Metal O2-Reduction Catalysts

Vasiliki Tileli, Robin Pierre Alain Girod, Secil Unsal

Non-noble metal catalysts (NNMCs) hold the potential to replace the expensive Pt-based materials currently used to speed up the oxygen reduction reaction (ORR) in proton exchange membrane fuel cell (PEMFC) cathodes, but they feature poor durability that in ...

AMER CHEMICAL SOC2023

Considerations of Liquid-Phase Transmission Electron Microscopy Applied to Heterogeneous Electrocatalysis

Vasiliki Tileli, Tzu-Hsien Shen, Robin Pierre Alain Girod, Jan Vávra

Liquid-phase transmission electron microscopy (LPTEM) is an essential tool for studying the dynamics of materials interactions at the nanoscale, in and/or with their operational environment. Microfabricated SiNx membrane cells further allow the integration ...

ELECTROCHEMICAL SOC INC2023

Induced giant piezoelectricity in centrosymmetric oxides

Dragan Damjanovic, Paul Muralt, Mahmoud Hadad, Vasiliki Tileli, Lukas Riemer, Daesung Park

Piezoelectrics are materials that linearly deform in response to an applied electric field. As a fundamental prerequisite, piezoelectric materials must have a noncentrosymmetric crystal structure. For more than a century, this has remained a major obstacle ...

American Association for the Advancement of Science2022

On the role of pore constrictions in gas diffusion electrodes

Yen-Chun Chen, Vasiliki Tileli, Robin Pierre Alain Girod, Michele Bozzetti

Water management by gas diffusion electrodes is a fundamental aspect of the performance of electrochemical cells. Herein, we introduce the characteristic constrictions size as a descriptor for microporous layers (MPL). This parameter is calculated by volum ...

Royal Society of Chemistry2022

Switchable wetting of oxygen-evolving oxide catalysts

Vasiliki Tileli, Tzu-Hsien Shen

The surface wettability of catalysts is typically controlled via surface treatments that promote catalytic performance. Here we report on potential-regulated hydrophobicity/hydrophilicity at cobalt-based oxide interfaces with an alkaline solution. The swit ...

NATURE PORTFOLIO2022

Latent Mechanisms of Polarization Switching from In Situ Electron Microscopy Observations

Vasiliki Tileli, Reinis Ignatans

In situ scanning transmission electron microscopy enables observation of the domain dynamics in ferroelectric materials as a function of externally applied bias and temperature. The resultant data sets contain a wealth of information on polarization switch ...

WILEY-V C H VERLAG GMBH2022

Decoding the Mechanisms of Phase Transitions from In Situ Microscopy Observations

Vasiliki Tileli, Reinis Ignatans

Analysis of the temperature- and stimulus-dependent imaging data toward elucidation of the physical transformations is an ubiquitous problem in multiple fields. Here, temperature-induced phase transition in BaTiO3 is explored using the machine learning ana ...

WILEY-V C H VERLAG GMBH2022

Challenges and Applications to Operando and In Situ TEM Imaging and Spectroscopic Capabilities in a Cryogenic Temperature Range

Martial Duchamp, Vasiliki Tileli, Reinis Ignatans

In this Account, we describe the challenges and promising applications of transmission electron microscopy (TEM) imaging and spectroscopy at cryogenic temperatures. Our work focuses on two areas of application: the delay of electron-beam-induced degradatio ...

AMER CHEMICAL SOC2021

Simulating Current Distribution of Oxygen Evolution Reaction in Microcells Using Finite Element Method

Vasiliki Tileli, Tzu-Hsien Shen

A three-dimensional finite element method (FEM) model simulating the electrochemical behaviour of Pt coplanar thin-film electrodes used for liquid cell transmission electron microscopy measurements was developed. The model included reaction kinetics and it ...

ELECTROCHEMICAL SOC INC2021

Multi-channel nanowire devices for efficient power conversion

Elison de Nazareth Matioli, Jun Ma, Vasiliki Tileli, Taifang Wang, Tzu-Hsien Shen, Catherine Erine, Luca Nela

Nanowire-based devices can potentially be of use in a variety of electronic applications, from ultrascaled digital circuits to 5G communication networks. However, the devices are typically restricted to low-power applications due to the relatively low elec ...

2021