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Concept

Alcali

Publications associées (31)

Palladium-based supramolecular assemblies: from complex structures to water-soluble anion-receptors

Sylvain Alexandre Marie Sudan

The combination of palladium salts and bipyridyl ligands can lead to the formation of a large variety of coordination complexes, with different shapes and sizes, displaying a very versatile host-guest chemistry. Increasing their structural complexity remai ...

EPFL2024

Photo-Fenton inactivation of MS2 bacteriophage at alkaline pH by Fe salts or nm to μm-sized oxides, and the Janus-faced effects of natural organic matter in surface waters

César Pulgarin, Stefanos Giannakis

In this study, MS2 bacteriophage was inactivated by homogeneous and heterogeneous photo-Fenton processes in an alkaline matrix (pH 8) using low concentrations of H2O2 and iron forms (1 mg/L), including Fe(II), Fe(III), and Fe (hydr)oxides. As a reference, ...

Elsevier2024

Effect of alkali, aluminium and equilibration time on calcium-silicate-hydrates

Yu Yan, Yiru Yan

Calcium silicate hydrate (C-S-H) is the main hydration product in Portland and blended cements, and greatly affects durability and mechanical properties of the hydrated cement. In the presence of Al-rich supplementary cementitious materials (SCMs), C-(A-)S ...

EPFL2022

Effect of alkali hydroxide on calcium silicate hydrate (C-S-H)

Karen Scrivener, Émilie Michèle L'Hôpital, Yu Yan

This paper investigates the effect of KOH and NaOH on C-S-H structure and solubility. Both KOH and NaOH have a similar effect, they increase pH values and silicon concentrations, and decrease calcium concentrations. At higher alkali hydroxide concentration ...

Pergamon-Elsevier Science Ltd2022

Al uptake in calcium silicate hydrate and the effect of alkali hydroxide

Karen Scrivener, Yan Yan

The effect of Al and of pH on the structure of calcium silicate hydrate (C-S-H), the most important hydration product in Portland and blended cement, was studied at Ca/Si similar to 1.0. The presence of Al led to higher amounts of secondary phases, larger ...

Pergamon-Elsevier Science Ltd2022

Reactivity of Multimetallic Thorium Nitrides Generated by Reduction of Thorium Azides

Rosario Scopelliti, Marinella Mazzanti, Luciano Barluzzi, Fang-Che Hsueh

Thorium nitrides are likely intermediates in the reported cleavage and functionalization of dinitrogen by molecular thorium complexes and are attractive compounds for the study of multiple bond formation in f-element chemistry, but only one example of thor ...

2022

The effect of paste composition, aggregate mineralogy and temperature on the pore solution composition and the extent of ASR expansion

Karen Scrivener, Mahsa Bagheri

The reaction kinetics of the alkali silica reaction depends on the composition of the pore solution. The evolution of the pore solution composition in different cement pastes and concretes was studied. Pastes containing silica fume or metakaolin had the lo ...

SPRINGER2022

Gradient Heating Epitaxial Growth Gives Well Lattice-Matched Mo2C-Mo2N Heterointerfaces that Boost Both Electrocatalytic Hydrogen Evolution and Water Vapor Splitting

Bowen Yang

An optimized approach to producing lattice-matched heterointerfaces for electrocatalytic hydrogen evolution has not yet been reported. Herein, we present the synthesis of lattice-matched Mo2C-Mo2N heterostructures using a gradient heating epitaxial growth ...

Wiley-VCH Verlag GmbH2022

The effect of alkali hydroxides and equilibration time on Al uptake by calcium silicate hydrates (C-S-H)

Sonya Barzgar

Cement production accounts for approximately 8% of man-made CO2 emissions. Lowering these CO2 emissions is currently one of the most important and urgent research topics within the cement community. To reduce these emissions, the Portland cement (PC) is pa ...

EPFL2021

Aggregate dissolution in different pore solutions

Mahsa Bagheri

The occurrence of cracking due to alkali silica reaction (ASR) affects the service life of concrete structures. The dissolution of silica-containing minerals within aggregates causes the formation of ASR products, which fill macroscopic cracks and cause th ...

EPFL2021

Advances in heterogeneous catalysis for the synthesis of polyoxymethylene dimethyl ethers

Christophe Jean Baranowski

Our society is engaged in a major shift towards more sustainable industries. The required transition from fossils to renewable resources with low greenhouse gas emission is specifically challenging in the transportation sector where high thermal efficiency ...

EPFL2020

Nanoscale Mass-Spectrometry Imaging of Grain Boundaries in Perovskite Semiconductors

Mohammad Khaja Nazeeruddin, Hiroyuki Kanda, Tom Theodorus Antonius Lummen, Iwan Zimmermann, Paul Gratia

Incorporation of alkali metals such as Cs+, Rb+, and K+ into hybrid organic-inorganic halide lead perovskites (HOIPs) generally improves the optoelectronic properties of HOIPs. However, it is still uncertain how alkali metals interact and distribute within ...

2020

Dual Photoredox/Copper Catalysis for the Remote C(sp3 )−H Functionalization of Alcohols and Alkyl Halides by N -Alkoxypyridinium Salts

Qian Wang, Jieping Zhu, Xu Bao

Under mild dual photoredox/copper catalysis, the reaction of N-alkoxypyridinium salts with readily available silyl reagents (TMSN3, TMSCN, TMSNCS) afforded d-azido, d-cyano, and d-thiocyanato alcohols in high yields. The reaction went through a domino proc ...

Wiley-VCH Verlag GmbH2019

An Unconventional Iron Nickel Catalyst for the Oxygen Evolution Reaction

Xile Hu, Anne-Clémence Corminboeuf, Michaël Bensimon, Fang Song, Michael Markus Busch

The oxygen evolution reaction (OER) is a key process that enables the storage of renewable energies in the form of chemical fuels. Here, we describe a catalyst that exhibits turnover frequencies higher than state-of-the-art catalysts that operate in alkali ...

2019

Orientation, rotation and solvation of ions in helium nanodroplets

Verónica Oliver Álvarez de Lara

Helium nanodroplets are liquid, finite size, nanoscale helium clusters that have been employed since the 1990s as a matrix for high-resolution spectroscopy of molecules. Spectroscopic studies of ionic species inside helium droplets were not however realise ...

EPFL2019

Synthesis and characterization of one-part geopolymers for extrusion based 3D concrete printing

Interest in innovative construction processes such as 3D concrete printing (i.e. digital construction), is growing rapidly both in academia and industry. Processing conventional geopolymer mixes, in which alkaline solutions are used for activation, could b ...

2019

Reversible Segregation of Nickel from Perovskite-type Oxides - Applications in Energy Processes

Patrick Simon Steiger

In this thesis, Ni catalysts derived from perovskite-type metal oxides (PMO, general formula ABO3, A=lanthanide or earth alkaline element, B=transition metal) are investigated as a potential class of materials, which are able to overcome thechallenges of c ...

EPFL2018

The Effect of Alkali on the Properties of Limestone Calcined Clay Cement (LC3)

Karen Scrivener, Wilasinee Hanpongpun

The impact of alkali content on the properties of Limestone Calcined Clay Cement (LC3) was investigated in this study. KOH was added in order to increase the alkali content of the blended cements from 0.44% Na2Oeq to 1.21% Na2Oeq. The increase of alkali ac ...

Springer2018

Transition Metal Oxides as Electrocatalysts for the Oxygen Evolution Reaction in Alkaline Solutions: An Application-Inspired Renaissance

Xile Hu, Lichen Bai, Fang Song, Laurent Liardet, Seunghwa Lee, Aliki Moysiadou

Water splitting is the essential chemical reaction to enable the storage of intermittent energies such as solar and wind in the form of hydrogen fuel. The oxygen evolution reaction (OER) is often considered as the bottleneck in water splitting. Though meta ...

2018

Ligand and Metal Based Multielectron Redox Chemistry of Cobalt Supported by Tetradentate Schiff Bases

Rosario Scopelliti, Marinella Mazzanti, Julie Renée Michelle Andrez

We have investigated the influence of bound cations on the reduction of cobalt complexes of redox active ligands and explored the reactivity of reduced species with CO2. The one electron reduction of [CoII(Rsalophen)] with alkali metals (M = Li, Na, K) lea ...

2017