Pierre Boillat

Properties of fluids in fuel gas systems (high pressure) and catalytic reactors (high temperature and pressure) are essential for their modeling but scarcely available. Liquid toluene and methylcyclohexane have been operando observed upon pressurization with hydrogen, methane, or ethane using Neutron Imaging (NI). Studied systems mimic phase separation in fuel gases, for which interfacial tension, Henry's law volatility constant, apparent molar volume, diffusion coefficient of dissolved methane and ethane are experimentally provided, interfacial tension is measured for systems with hydrogen. This uniquely extensive basis of coupled experimental quantities has been compared with their Molecular Dynamics (MD) model predictions. Moreover, predictions of quantities inaccessible using NI, such as self‐diffusion coefficients, partial molar volumes, enthalpies and entropies of dissolution, or parameters of the Lennard‐Jones potential shed light on liquids exposed to fuel gases at high pressures. The MD model generally predicts system properties emerging from intermolecular interactions and can thus be used beyond the temperature and pressure limitations of the validation experiment. Following this concept, previously inaccessible diffusion coefficients in model bulk fluids mimicking the catalytic (de)hydrogenation of toluene are provided. This paves the way to detailed modeling of catalytic conversions in this Liquid Organic Hydrogen Carrier system.

Operando visualization of ultrathin lithium is essential for understanding plating and stripping in lithium-metal batteries, but existing neutron imaging techniques lack sufficient sensitivity for ultra-thin lithium layers formed at crucial early stages. Here we introduce neutron capture imaging (NCI), which selectively detects tritons generated by neutron capture in ⁶ Li. Ex situ measurements of electrochemically plated and thermally evaporated ⁶ Li demonstrate sensitivity around 10 nm for a 1.5 h acquisition and two-dimensional imaging with around 100 μm lateral resolution. Simulations indicate that the resolution could approach 25 μm through optical optimization. Operando measurements in an asymmetric Cu|| ⁶ Li cell reveal spatially heterogeneous lithium plating and stripping in agreement with electrochemical data. Our results establish NCI as a high-sensitivity, near-zero-background tool for operando studies of lithium metal batteries, opening new possibilities for resolving early-stage deposition, dead lithium formation, and interfacial dynamics with broad applicability to ultrathin reactive lithium layers in electrochemical systems.

Fuel cell efficiency and cost reductions can be enhanced by using interdigitated flow fields (IFFs) instead of conventional parallel channels, as they allow oxygen convective flow through the gas diffusion layer (GDL). However, water accumulation at the end of the inlet of interdigitated channels poses a risk to operational stability at high current densities when conventional hydrophobic GDLs are used. This study aims to optimize the flow field architecture, land width, channel geometry, and hydrophilic patterns in the GDL to favor electrochemical performance and operational stability. The combination of IFFs with a land width of 1 mm and a patterned GDL improves the cell performance by ∼70 mV at 2 A cm ⁻² and an air-stoichiometry of 1.2 compared to the use of a purely hydrophobic GDL. Increasing the IFFs’ land width to 4 mm, even with a hydrophobic GDL, enabled the operation at an air-stoichiometry of 1.2 and at 2 A cm ⁻² with a loss of only 44 mV with regards to an air-stoichiometry of 2. Thus, optimizing the GDL wettability distribution and flow field parameters has a great impact on the cell performance, enabling a more stable operation at high current densities and low cathode stoichiometries.

The determination of interfacial energy (hence interfacial tension) from the shapes of mobile interfaces in cylindrical tubes is a rather viable though seldom utilized method despite the relative ease of its implementation. In this work, neutron imaging is used to reveal the shapes of interfaces in the system of perdeuterated p -xylene ( p -C ₈ D ₁₀ ) layered over water (10.88 mol.% of H ₂ O in D ₂ O) and exposed to pressurized methane (CH ₄ , from 1.0 to 101 bar) at 7.0 to 30.0 ℃ while enclosed in the titanium tubular cell. These non-tactile measurements are performed using relatively high spatial resolution (pixel size 20.3 μm). The sensitivity limits determining the uncertainty of thus derived interfacial tensions are analyzed. Interfacial tension for methane – p -xylene was determined at the experimental uncertainty of 2 mN⋅m ⁻¹ . Interfacial tension for p -xylene – water was estimated at the experimental uncertainty of 16 mN.m ⁻¹ . Water and p -xylene are severe formers of freeze-out from moist and/or hydrocarbons containing natural gas. We survey the conditions needed for the interfacial tension measurements of industrially very relevant systems with prospects of acceptable experimental uncertainties while utilizing the intrinsically straightforward and on the first principles based methodology.

In polymer electrolyte fuel cells (PEFCs), temperature gradients can exert a substantial influence on cell performance and durability. Monitoring these gradients without perturbing fuel cell operation is one of the main challenges. This study introduces a novel method for remotely mapping fuel cell temperature using ferromagnetic nanoparticles, such as nickel and iron. These nanomediators possess temperature-dependent magnetic properties, enabling neutron depolarization imaging (NDI) to provide insights into the internal fuel cell temperature. We extensively evaluated the main parameters pertaining to the utilization of these nanoparticles in powdered form for temperature sensing. This encompassed an assessment of the minimum detection concentration and temperature sensitivity. Our findings reveal that while the smallest nanoparticles yield the highest relative change in depolarization, they exhibit considerably lower absolute depolarization coefficients. Hence, larger particles emerge as strong candidates for signal detection. Despite the challenges posed by the considerable size of these sensors, which inhibits in-situ dispersion, there is an opportunity to enhance nanoparticle characteristics. Such improvements could be achieved by scaling up the size of the materials from the nanoscale while retaining high magnetic saturation and temperature sensitivity.

Pressurized gases adsorb on the gas‐liquid ( g ‐ l ) interfaces, thus reducing the interfacial tension (IFT). Gas‐saturated liquid–liquid ( l ‐ l ) emulsions occur in oil and gas wells, possible IFT changes due to saturation remain unclear. We study if the IFT reduction occurs for the model system of methane, p‐ xylene, and water. The neutron imaging (NI) observations of bulk ( g ‐ l ‐ l ) systems at 100 bar provide several quantities simultaneously from each experimental run, e.g., IFT for g ‐ l and methane diffusivity for the p‐ xylene rich phase, but does not sensitively provide IFT for the l ‐ l interface. The quantities derived for the p‐ xylene‐rich phase using NI allows us to calibrate molecular dynamics (MD) simulation, which is used for the predictions of IFT for l ‐ l , literature data for binary benzene/water ( l ‐ l ) system are used as the reference. Overall, no, or very minor effect (±1 mN m ^{− 1} ) on IFT is robustly found up to methane saturation at 100 bar. Variation of partial charges on the p ‐xylene model from zero to quantum calculation‐based modulate the fine structure of p ‐xylene/water interface and has small, yet qualitative effect on IFT, resulting in a weak adsorption (−1 mN m ⁻¹ ), or weak depletion (+1 mN m ⁻¹ ) of methane from l‐l .

This study uses operando neutron imaging and electrochemical data to reveal how flow field geometry and electrode structure shape concentration profiles and transport dynamics in organic redox flow cells.

Fascioliasis, a significant foodborne parasitic disease, is transmitted via Lymnaea natalensis snails. This study evaluated the molluscicidal activities of Senna alata ethanolic extracts and its green-synthesized silver nanoparticles (AgNPs) against adult L. natalensis and its ova. AgNPs were synthesized using S. alata leaf extract, confirmed by UV-visible spectroscopy with an absorption peak at 362 nm. Characterization via XRD revealed crystalline peaks at 2θ values of 25.50°, 30.50°, and 38.00°, while SEM showed irregularly shaped particles averaging 20.32 nm with an elemental composition of 47.04% silver. FTIR identified key functional groups, including aromatic C–H stretching (3016.39 and 3098.26 cm⁻¹) and O–H stretching of phenolics. Molluscicidal assays demonstrated that AgNPs achieved 100% snail mortality within 40 min at 0.167 mg/mL, significantly outperforming crude extracts (60% mortality at 5 mg/mL after 24 h; p < 0.05). The green-synthesized molluscicide AgNPs halted embryonic development at the blastula stage at all concentrations, whereas crude extracts showed minimal effects. Oxidative stress markers in snails exposed to AgNPs indicated elevated lipid peroxidation (p < 0.01) and catalase activity (p < 0.05), alongside reduced superoxide dismutase activity (p < 0.05). SDS-PAGE analysis revealed altered protein expression, with new bands at 17–95 kDa in AgNP-exposed snails. These findings highlight S. alata-AgNPs as a potent, eco-friendly molluscicide, effective at low concentrations. Further studies on environmental safety and field applications are recommended.

Visualizing multiphase (solid–liquid–gas) electrochemical transformations during operation is essential to advancing sustainable energy storage technologies. All-iron redox flow batteries represent a promising candidate due to their low-cost, earth-abundant materials; however, they suffer from uneven plating rates, cycling instability, and parasitic hydrogen evolution. Here, we introduce an operando neutron imaging methodology – combining polarized and transmission modes – to simultaneously track iron plating/stripping and hydrogen evolution. We uncover preferential iron deposition near the membrane indicating a non-uniform current density distribution. We find that pH plays a major role in reaction selectivity and cycling performance, where less acidic pH results in inaccessible iron deposits. Our experiments with different flow field geometries show that both reaction selectivity and spatial distribution are strongly influenced by electrolyte flow patterns. This multimodal imaging approach provides critical insights into reactive transport and multiphase behavior in flow batteries.