Energy and Environment Research Division
Research at PSI comprises all aspects of human energy use, with the ultimate goal of promoting development towards a sustainable energy supply system. Technologies are being advanced for the utilization of renewable energy sources, low-loss energy storage, efficient conversion, and low emission energy use. Experimental and model-based assessment of these emissions forms the basis of a comprehensive assessment of economic, environmental and social consequences, for both present and future energy supply systems.
Division Head: Prof. Dr. Thomas Justus Schmidt
Energy Briefing Event 2022
On June 28th, 2022, the Energy Divisions (ENE and NES) at PSI hosted their first Energy Briefing Event at the Kursaal in Bern. Knowledgeable voices from industry, research and government shared insights in a dialogue on the feasibility of the Net Zero goal and what next steps are required to achieve this collectively.
A big thank you to Daniela Decurtins (GazEnergy), Particia Sandmeier (Hitachi Energy), Martin Naef (ABB), Pascal Previdoli (BFE), Thomas Schmidt (PSI), Christian Verhoeven (GE), Peter Richner (Empa), Andreas Pautz (PSI) and our Moderator Stephan Lendi for their valuable contributions and insights!
Highlights & News
Effect of surface charge density on the affinity of oxide nanoparticles for the vapor–water interface
Using in-situ X-ray photoelectron spectroscopy at the vapor-water interface, the affinity of nanometer-sized silica colloids to adsorb at the interface is shown to depend on colloid surface charge density. In aqueous suspensions at pH 10 corrected Debye-Hückel theory for surface complexation calculations predict that smaller silica colloids have increased negative surface charge density that originates from enhanced screening of deprotonated silanol groups by counterions in the condensed ion layer.
Understanding the molecular behaviour of frozen water is essential for predicting the future of our planet, says Thorsten Bartels-Rausch.
Variations in diesel soot reactivity along the exhaust after-treatment system, based on the morphology and nanostructure of primary soot particles
The reactivity of soot at different sites of the exhaust after-treatment system of a diesel engine (upstream and downstream of the diesel oxidation catalyst (DOC), downstream of the diesel particulate filter (DPF), as well as inside the DPF) was investigated on the basis of morphology and structure of primary soot particles by high resolution transmission electron microscopy (HRTEM). The results indicate that combustion-formed soot particles are susceptible to further transformations of their morphology within the exhaust system.
Supported gold as catalyst for the decomposition of ammonia precursors in the selective catalytic reduction of NOx
Titaniumdioxide supported gold was found to catalyze the hydrolysis of formate-based ammonia precursor compounds which are proposed for the selective catalytic reduction of nitrogen oxides (NOx) in combustion exhaust gas. In contrast to other noble metals, the supported gold does not oxidize the released NH3, while it maintains decomposition of intermediate formic acid.
Human activities have significantly altered atmospheric Pb concentrations and thus, its geochemical cycle, for thousands of years. Whereas historical Pb emissions from Western Europe, North America, and Asia are well documented, there is no equivalent data for Eastern Europe. Here, we present ice-core Pb concentrations for the period 1680à1995 from Belukha glacier in the Siberian Altai, assumed to be representative of emissions in Eastern Europe and the Altai.
Gold particles supported on carbon when subjected to a flow of methyl iodide or bromide redisperse from large ensembles to single atoms and/or dimers of gold. Methyl halide oxidizes gold leading to gradual particle dissolution. The process could be carried out at temperatures as low as 50 °C. The excess of halide could be removed by a post-treatment of the material with 1%H2O/H2, which does not influence the metal dispersion. This remarkable transformation opens the possibility of re-activating gold catalysts that lost their performance due to metal particles sintering.
Organic substances can adopt an amorphous solid or semisolid state, influencing the rate of heterogeneous reactions and multiphase processes in atmospheric aerosols. Here we demonstrate how molecular diffusion in the condensed phase affects the gas uptake and chemical transformation of semisolid organic particles. Flow tube experiments show that the ozone uptake and oxidative aging of amorphous protein is kinetically limited by bulk diffusion.
The role of long-lived reactive oxygen intermediates in the reaction of ozone with aerosol particles
The heterogeneous reactions of ozone with aerosol particles are of central importance to air quality. They are studied extensively, but the molecular mechanisms and kinetics remain unresolved. Based on new experimental data and calculations, we show that long-lived reactive oxygen intermediates (ROIs) are formed. The chemical lifetime of these intermediates exceeds 100 seconds, which is much longer than the surface residence time of molecular ozone (~ ns).
A Mt. Everest ice core spanning 1860à2000 AD and analyzed at high resolution for black carbon (BC) using a Single Particle Soot Photometer demonstrates strong seasonality, with peak concentrations during the winter‐spring, and low concentrations during the summer monsoon season. BC concentrations from 1975à2000 relative to 1860à1975 have increased approximately threefold, indicating that BC from anthropogenic sources is being transported to high elevation regions of the Himalaya.