Publications by Jan Vávra | EPFL Graph Search

Solution-based Cu+ transient species mediate the reconstruction of copper electrocatalysts for CO2 reduction

Raffaella Buonsanti, Anna Loiudice, Petru Pasquale Albertini, Jan Vávra, Gaétan Philippe Louis Ramona

Understanding metal surface reconstruction is of the utmost importance in electrocatalysis, as this phenomenon directly affects the nature of available active sites. However, its dynamic nature renders surface reconstruction notoriously difficult to study. ...

Nature Portfolio2024

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

Copper-Phosphonate Lamella Intermediates Control the Shape of Colloidal Copper Nanocrystals

Raffaella Buonsanti, Petru Pasquale Albertini, Dragos-Constantin Stoian, Jan Vávra, James Richard Pankhurst, Valeria Mantella

Understanding the structure and behavior of intermediates in chemical reactions is key to developing greater control over the reaction outcome. This principle is particularly important in the synthesis of metal nanocrystals (NCs), where the reduction, nucl ...

2022

The native oxide skin of liquid metal Ga nanoparticles prevents their rapid coalescence during electrocatalysis

Raffaella Buonsanti, Anna Loiudice, Dragos-Constantin Stoian, Jan Vávra, Valery Okatenko, Laia Castilla Amorós

Liquid metals (LMs) have been used in electrochemistry since the 19th century, but it is only recently that they have emerged as electrocatalysts with unique properties, such as inherent resistance to coke-poisoning, which derives from the dynamic nature o ...

2022

Monitoring and understanding Cu catalyst dissolution during CO2 electroreduction

Jan Vávra

Electrochemical reduction of carbon dioxide is a promising approach to decrease the amount of anthropogenic CO2 being released into the atmosphere, provided that a surplus of renewable electrical energy is available. Copper based materials are at the cente ...

EPFL2022

Photoluminescence emission induced by localized states in halide-passivated colloidal two-dimensional WS2 nanoflakes

Raffaella Buonsanti, Anna Loiudice, Jan Vávra, Michele Saba

Engineering physicochemical properties of two-dimensional transition metal dichalcogenide (2D-TMD) materials by surface manipulation is essential to enabling their practical and large-scale application. This is especially challenging for colloidal 2D-TMDs ...

Royal Society of Chemistry2021

Synthetic Tunability of Colloidal Covalent Organic Framework/Nanocrystal Hybrids

Raffaella Buonsanti, Seyedehbehnaz Varandili, Jan Vávra, Chethana Janardhana Gadiyar, Vikram Vinayak Karve, Ona Segura Lecina, Yannick Thomas Guntern

The combination of porous reticular frameworks and nanocrystals (NCs) offers a rich playground to design materials with functionalities, which are beneficial for a large variety of applications. Achieving compositional and structural tunability of these hy ...

2021

Real-time Monitoring Reveals Dissolution/Redeposition Mechanism in Copper Nanocatalysts during the Initial Stages of the CO2 Reduction Reaction

Raffaella Buonsanti, Vasiliki Tileli, Dragos-Constantin Stoian, Tzu-Hsien Shen, Jan Vávra

Size, morphology, and surface sites of electrocatalysts have a major impact on their performance. Understanding how, when, and why these parameters change under operating conditions is of importance for designing stable, active, and selective catalysts. He ...

Wiley-VCH Verlag GmbH2021

Elucidating the structure-dependent selectivity of CuZn towards methane and ethanol in CO2 electroreduction using tailored Cu/ZnO precatalysts

Raffaella Buonsanti, Seyedehbehnaz Varandili, Kevin Rossi, Dragos-Constantin Stoian, Jan Vávra, James Richard Pankhurst, Yannick Thomas Guntern

Understanding the catalyst compositional and structural features that control selectivity is of uttermost importance to target desired products in chemical reactions. In this joint experimental-computational work, we leverage tailored Cu/ZnO precatalysts a ...

2021

Colloidal Nanocrystals as Electrocatalysts with Tunable Activity and Selectivity

Raffaella Buonsanti, Seyedehbehnaz Varandili, Cedric David Koolen, Dragos-Constantin Stoian, Jan Vávra, James Richard Pankhurst, Valery Okatenko, Pranit Srinivas Iyengar

Correlating the catalyst activity, selectivity, and stability with its structure and composition is of the utmost importance in advancing the knowledge of heterogeneous electrocatalytic processes for chemical energy conversion. Well-defined colloidal nanoc ...

2021