News & Highlights

The development of strategies and policies aiming at the reduction of environmental exposure to air pollution requires the assessment of historical emissions. Although anthropogenic emissions from the extended territory of the Soviet Union (SU) considerably influenced concentrations of heavy metals in the Northern Hemisphere, Pb is the only metal with long-term historical emission estimates for this region available, whereas for selected other metals only single values exist.

The high-energy rechargeable Li-O₂ battery has been subject to intensive research worldwide during the past years. The Li-O₂ cell mainly comprises a negative (e.g. Li metal) and positive (e.g. porous carbon) electrode separated by an electronically insulating, but Li+ conducting electrolyte layer. In order to study the cell chemistry, a differential electrochemical mass spectrometry setup based on a set of valves, a pressure sensor and a quadrupole mass spectrometer has been developed.

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.

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.

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.