Véronique Amstutz

HES-SO Valais-Wallis | HES-SO · Institute of Life Technology

Polyhydroxyalkanoates (PHA) are renewable alternatives to traditional oil-derived polymers. PHA can be produced by different microorganisms in continuous culture under specific media composition, which makes the production process both promising and challenging. In order to achieve large productivities while maintaining high yield and efficiency, t...

Polyhydroxyalkanoates (PHAs) are accumulated intracellularly by many bacteria and serve as a carbon and energy storage compound. PHAs are polyesters of high molecular weight and can be isolated by solvent extraction and precipitation in antisolvents. The material properties of PHAs are of great interest due to the inherent biodegradability and exce...

In the context of the ongoing discussion of accumulating plastic debris in the environment, this article summarizes recent reports on the topic of microplastic pollution. Moreover, it gives an overview of the results from the activities of the research group for Biotechnology and Sustainable Chemistry of the Institute of Life Technologies at the HE...

The incessant growth in energy demand has resulted in the deployment of renewable energy generators to reduce the impact of fossil fuel dependence. However, these generators often suffer from intermittency and require energy storage when there is over-generation and the subsequent release of this stored energy at high demand. One such energy storag...

In 2015 the annual average concentration of atmospheric CO2 rose for the first time above 400 ppm. This raise was clearly related to ever-growing industrial activity and combustion of petrol and its related products, for example, plastics, which annual global production is over 300 Mio tons. An interesting option to approach this problem is the bio...

The accurate and reproducible large-scale production of catalyst layers containing low-cost, abundant electrocatalysts gains in importance. Herein, pivotal factors are discussed that need to be considered when a combined inkjet printing and photonic curing platform is used as a promising fabrication method for catalyst layers based on a model low-c...

In this work, the viability of polyaniline as a solid charge storage material in an aqueous redox-mediated flow battery is investigated. Fe(III/II) and V(IV/III) were identified as potential redox mediators to target the emeraldine-pernigraniline and leucoemeraldine-emeraldine redox transitions of the polymer. An indirect chemical cycling method wa...

The improvement of silica particle codeposition into a nickel electrodeposited composite coating (ECC) by a double face horizontal impinging jet cell (IJC) has been studied. The microstructure of coatings was examined by means of scanning electron microscopy performed in backscattered electron mode. The embedded particles distribution was shown to...

Electrocatalysis of water oxidation was achieved using fluorinated tin oxide (FTO) electrodes modified with layer-by-layer deposited films consisting of bilayers of negatively charged citrate-stabilized IrO2 NPs and positively charged poly(diallyldimethylammonium chloride) (PDDA) polymer. The IrO2 NP surface coverage can be fine-tuned by controllin...

Vanadium Redox Flow Batteries (VRFB) can be used as energy storage device, for example to account for wind or solar power fluctuations. In VRFBs charge is stored in two tanks containing two different vanadium solutions. This approach decouples the storage capacity and the power supply which is dependent only on the number and size of the cells [1]....

Silicon and Silicon carbide particles have been investigated by the mean of infrared (IR) spectroscopy and X-ray photoelectron spectroscopy (XPS) to establish their surface states. The results of this research are based on the estimation of the area under the high resolution peaks by isosceles triangles. This approach leads to the repartition of th...

An electrochemical cell consisting of a double horizontal Impinging Jet Cell (IJC) has been conceived and characterized. The purpose of this system is the simultaneous electrodeposition of a composite metal/particle coating on both surfaces of a metal sheet. The silica particles imprint in the nickel matrix has allowed to distinguish four different...

Social, economic, and political pressures are causing a shift in the global energy mix, with a preference toward renewable energy sources. In order to realize widespread implementation of these resources, large-scale storage of renewable energy is needed. Among the proposed energy storage technologies, redox flow batteries offer many unique advanta...

An all-vanadium dual circuit redox flow battery is an electrochemical energy storage system able to function as a conventional battery, but also to produce hydrogen and perform desulfurization when a surplus of electricity is available by chemical discharge of the battery electrolytes. The hydrogen reactor chemically discharging the negative electr...

Inkjet printing is a very powerful digital and mask-less microfabrication technique that has attracted the attention of several research groups working on electrochemical energy conversion concepts. In this short review, an overview is given about recent efforts to employ inkjet printing for the search of new electrocatalyst materials and for the p...

Polyacrylamide (PA) based hydrogels are used in several applications including polyacrylamide gel electrophoresis and sensing devices. Homogeneous and compact PA films can be prepared based on chemical or photopolymerization processes. However, the accurate and reproducible coating of substrates with nanohydrogel patterns is challenging due to the...

The progressive integration of renewable energy sources such as wind turbines and photovoltaic pannels in the current electrical network, and the rise of the electrical mobility, provoke a change of paradigm in the sector of energy management. The increasing variability of the electricity production and consumption profiles, together with the requi...

Water oxidation catalysed by iridium oxide nanoparticles (IrO 2 NPs) in water–acetonitrile mixtures using [Ru III (bpy) 3 ] 3+ as oxidant was studied as a function of the water content, the acidity of the reaction media and the catalyst concentration. It was observed that under acidic conditions (HClO 4) and at high water contents (80% (v/v)) the r...

Redox flow batteries (RFBs) are particularly well suited for storing the intermittent excess supply of renewable electricity, so-called “junk” electricity. Conventional RFBs are charged and discharged electrochemically, with electricity stored as chemical energy in the electrolytes. In the RFB system reported here, the electrolytes are conventional...

Face to face: Flakes of reduced graphene oxide, synthesized in situ at the liquid/liquid interface from a graphene-oxide precursor, are capable of catalyzing the biphasic reduction of protons to hydrogen peroxide in the presence of molecular oxygen and an organic solubilized electron donor. This offers a new perspective for the bulk production of a...

Gold nanoparticle (Au NP) mirrors, that exhibit both high reflectance and electrical conductance, were self-assembled at a [heptane + 1,2-dichloroethane]/water liquid/liquid interface. The highest reflectance, as observed experimentally and confirmed by finite difference time domain (FDTD) calculations, occurred for Au NP films consisting of 60 nm...

Rarely reported low-cost molybdenum boride and carbide microparticles, both of which are available in abundant quantities due to their widespread use in industry, adsorb at aqueous acid-1,2-dichloroethane interfaces and efficiently catalyse the hydrogen evolution reaction in the presence of the organic electron donor - decamethylferrocene. Kinetic...

Recent studies have shown that electrolysis can be an efficient process for nitrogen removal from urine. These studies have been conducted with urea solutions or fresh urine, but urine collected in NoMix toilets and urinals has a substantially different composition, because bacteria hydrolyse urea quickly to ammonia and carbonate. In this study, we...

1 Les batteries redox pour le stockage d'énergie Des applications conventionnelles à la production d'hydrogène Le stockage de l'énergie est un élément-clé pour l'inté-gration des énergies renouvelables dans le mix élec-trique. Parmi les technologies électrochimiques, les batteries redox offrent des avantages particulièrement intéressants pour le st...