Publications associées à Énergie d'activation

Local vs. cooperative: Unraveling glass transition mechanisms with SEER

Which phenomenon slows down the dynamics in supercooled liquids and turns them into glasses is a long-standing question of condensed matter. Most popular theories posit that as the temperature decreases, many events must occur in a coordinated fashion on a ...

National Academy of Sciences2024

Probing Water Dissociation and Oxygen Replacement on Partially Oxygen-Covered Cu(111) by Reflection Absorption Infrared Spectroscopy

Rainer Beck, Mateusz Suchodol, Harmina Vejayan

The presence of chemisorbed oxygen on the Cu(111) surface is known to strongly reduce the activation barrier for water dissociation as compared to bare Cu(111). Here, we present direct experimental evidence for the hydrogen abstraction mechanism responsibl ...

2023

High entropy molybdate-derived FeOOH catalyzes oxygen evolution reaction in alkaline media

Lichen Bai, Seunghwa Lee

High-entropy materials are a new class of materials that have lately been developed and applied to a variety of potential fields. Here we present that electrochemical activation facilitates the application of high-entropy molybdates (HEMo) as oxygen evolut ...

PERGAMON-ELSEVIER SCIENCE LTD2023

Bending and Stretching in a Narrow Ribbon of Nematic Polymer Networks

Harmeet Singh

We study the spontaneous out-of-plane bending of a planar untwisted ribbon composed of nematic polymer networks activated by a change in temperature. Our theory accounts for both stretching and bending energies, which compete to establish equilibrium. We s ...

SPRINGER2023

Chlorination of amides: Kinetics and mechanisms of formation of N-chloramides and their reactions with phenolic compounds

Urs von Gunten, Tianqi Zhang

Amides are common constituents in natural organic matter and synthetic chemicals. In this study, we investi-gated kinetics and mechanisms of the reactions of chlorine with seven amides, including acetamide, N-meth-ylformamide, N-methylacetamide, benzamide, ...

2023

Anisotropic In-Plane strain engineering Ni(OH)2 to activate alkaline hydrogen evolution reaction

Kangning Zhao, Chao Yang

Realizing a hydrogen economy strongly requires alkaline water electrolysis to achieve large-scale generation of H2, but lacks stable and efficient catalysts. The insufficient active sites in Ni(OH)2 impair the catalytic performance of alkaline HER. Herein, ...

ELSEVIER SCIENCE SA2023

Gas/Surface reactions probed by reflection absorption infrared spectroscopy

Harmina Vejayan

In my thesis, I present an investigation of the dissociation reactions of gas phase molecules on single crystal metal surfaces studied by a molecular beam in combination with Reflection Absorption Infrared Spectroscopy (RAIRS). Two gas/surface systems were ...

EPFL2023

Hiding in Plain Sight: The Issue of Hidden Variables

Yimon Aye, Mahdi Assari

Here we discuss "hidden variables", which are typically introduced during an experiment as a consequence of the application of two independent variables together to create a stimulus. With increased sophistication in modern chemical biology tools and relat ...

AMER CHEMICAL SOC2022

Oxygen diffusion in garnet: Experimental calibration and implications for timescales of metamorphic processes and retention of primary O isotopic signatures

Anders Meibom, Stéphane Laurent Escrig

Knowledge of oxygen diffusion in garnet is crucial for a correct interpretation of oxygen isotope signatures in natural samples. A series of experiments was undertaken to determine the diffusivity of oxygen in garnet, which remains poorly constrained. The ...

MINERALOGICAL SOC AMER2022

Mechanistic modelling of solar disinfection (SODIS) kinetics of Escherichia coli, enhanced with H2O2 - Part 2: Shine on you, crazy peroxide

César Pulgarin, Stefanos Giannakis, Ling Feng

In this second part of the development of a mechanistic kinetic model of the solar inactivation of E. coli enhanced with hydrogen peroxide, we evaluate the mechanisms based on photonic inactivation and integrate them into the kinetic model of the dark proc ...

ELSEVIER SCIENCE SA2022

Migrative Carbofluorination of Saturated Amides Enabled by Pd-Based Dyotropic Rearrangement

Qian Wang, Jieping Zhu, Anne-Clémence Corminboeuf, Hua Wu, Simone Gallarati, Guoqiang Yang

Directly editing an all-carbon quaternary carbon itself of nonstrained acyclic molecules remains underexploited despite the recent advances in the fields of both C–H and C–C bond activation. Herein, we report a palladium-catalyzed migrative carbofluorinati ...

ACS2022

Demonstrating and Unraveling a Controlled Nanometer-Scale Expansion of the Vacancy Defects in Graphene by CO2

Kumar Varoon Agrawal, Kuang-Jung Hsu, Luis Francisco Villalobos Vazquez de la Parra

A controlled manipulation of graphene edges and vacancies is desired for molecular separation, sensing and electronics applications. Unfortunately, available etching methods always lead to vacancy nucleation making it challenging to control etching. Herein ...

Wiley-VCH Verlag GmbH2022

Mapping Catalyst‐Solvent Interplay in Competing Carboamination/Cyclopropanation Reactions

Nicolai Cramer, Matthew Wodrich, Anne-Clémence Corminboeuf, Miyeon Chang, Simone Gallarati

Group 9 metals, in particular Rh III complexes with cyclopentadienyl ligands, are competent C–H activation catalysts. Recently, a Cp*Rh III catalyzed reaction of alkenes with N -enoxyphthalimides showed divergent outcome based on the solvent, with carboami ...

2022

Mechanistic modelling of solar disinfection (SODIS) kinetics of Escherichia coli, enhanced with H2O2 - part 1: The dark side of peroxide

César Pulgarin, Stefanos Giannakis, Ling Feng

The present bi-partite work describes the development and validation of a mechanistic kinetic model of SODIS E. coli inactivation, enhanced with H2O2. In this first part, the mechanism of the baseline dark phenomena is modelled. A mechanistic model involvi ...

ELSEVIER SCIENCE SA2022

Support-Dependent Cu-In Bimetallic Catalysts for Tailoring the Activity of Reverse Water Gas Shift Reaction

Thi Ha My Pham, Wen Luo, Kun Zhao, Mo Li, Youngdon Ko, Liping Zhong

Cu-based bimetallic catalysts have attracted great attention for the reverse water gas shift (RWGS) reaction due to their high activity and selectivity. This work reports the application of Cu-In bimetallic catalysts for the RWGS reaction and demonstrates ...

AMER CHEMICAL SOC2022

Molecular dynamics simulations of the evaporation of hydrated ions from aqueous solution

Philip Robin Loche

Although important for atmospheric processes and gas-phase catalysis, very little is known about the hydration state of ions in the vapor phase. Here we study the evaporation energetics and kinetics of a chloride ion from liquid water by molecular dynamics ...

NATURE PORTFOLIO2022

Relaxation time shift of Cobalt related internal friction peak in WC-Co cemented carbide

Daniele Mari, Lucas Eric Jacques Degeneve, Samy Adjam

Cemented carbides are widely used in the cutting tools industry for their mechanical properties. They are composite materials made of hard tungsten carbide grains jointed together by a ductile cobalt binder. Due to the extreme conditions of use of the tool ...

ELSEVIER SCIENCE SA2022

Mitochondrial respiratory chain dysfunction disrupts intracellular cholesterol homeostasis

Christopher Tadhg James Wall

Mitochondrial diseases are rare and severe conditions with debilitating symptoms. Biochemical defects in mitochondria however are common. The difference between these two frequencies is suspected to lie in the capability of the cells to adapt to the homeos ...

EPFL2022

Using Novel Molecular-Level Chemical Composition Observations of High Arctic Organic Aerosol for Predictions of Cloud Condensation Nuclei

Julia Schmale, Andrea Baccarini, Lubna Dada

Predictions of cloud droplet activation in the late summertime (September) central Arctic Ocean are made using κ-Köhler theory with novel observations of the aerosol chemical composition from a high-resolution time-of-flight chemical ionization mass spectr ...

2022

Investigating Tetrel-Based Neutral Frustrated Lewis Pairs for Hydrogen Activation

Shubhajit Das

Tetrel Lewis acids are a prospective alternative to commonly employed neutral boranes in frustrated Lewis pair (FLP) chemistry. While cationic tetrylium Lewis acids, being isolobal and iso(valence)electronic, are a natural replacement to boranes, neutral t ...

AMER CHEMICAL SOC2021