Unraveling degradation processes in a bipolar membrane CO2 electrolyzer by time-resolved X-ray tomographic microscopy
Employing a bipolar ion conducting membrane (BPM) in forward bias is a convenient solution for the biggest issues in the more common anion exchange membrane (AEM) CO2 co-electrolysis: the degradation of the performance caused by carbonate salt precipitation at the cathode and the decrease of net CO2 conversion caused by the crossover of this molecule from cathode to anode also requiring energy for downstream gas separation. However, the performance and stability of this device remain largely insufficient when using such a BPM configuration. To understand the reasons for this, we performed time-resolved X-ray tomographic microscopy of an operating BPM CO2 electrolyzer. The imaging method reveals partly unexpected degradation processes that result in design recommendations for improvement.
Part I: How the Jungfrau detector went from inception to perfection to ubiquity.
Experiments at the Swiss Light Source SLS prove the existence of a new type of magnetism, with broad implications for technology and research.
One of the recipes for realizing topological superconductivity calls for interfacing a topological insulator with a superconductor. In a variant of that approach, Yi et al. grew a heterostructure consisting of layers of a magnetic topological insulator, (Bi,Sb)2Te3 doped with chromium, and antiferromagnetic iron telluride. Neither of these materials is superconducting, but iron telluride is a parent compound for a family of iron-based superconductors. Interfacing the layers led to the appearance of superconductivity in the presence of ferromagnetism and topological band structure. This combination of properties makes the heterostructure a promising, although not yet proven, platform for observing chiral topological superconductivity.
Experiments at the Swiss Light Source (SLS) show the potential of extreme ultraviolet light (EUV) to make the building blocks of scalable quantum computers.
Insights into the superior oxygen evolution reaction activity of CoOx/CeO2 composite electrocatalyst
CeO2 significantly enhances the oxygen evolution reaction (OER) activity of CoOx, although the mechanism behind this synergy is still unclear. Here, operando hard X-ray absorption spectroscopy (hXAS) is applied to monitor the Co-K edge and Ce L3 edge in CoOx/CeO2 to shed light on the evolution of Co and Ce oxidation states during OER. In addition, ex situ soft XAS (sXAS) characterizations provide information on the irreversible surface-specific transformations of the Co L3 edge as well as the O K edge.
"Magnetostriction-Driven Muon Localization in an Antiferromagnetic Oxide" published in Phys. Rev. Lett.
A study involving PSI scientists from the LMS lab, and just published in Physical Review Letters has found that in manganese oxide, a textbook antiferromagnetic material, the site of an implanted spin-polarized muon is not well identified, but can change due to a previously neglected effect: magnetostriction.
Magnetostriction results from the coupling between magnetic and elastic degrees of freedom. Though it is associated with a relatively small energy, we show that it plays an important role in determining the site of an implanted muon, so that the energetically favorable site can switch on crossing a magnetic phase transition. This surprising effect is demonstrated in the cubic rocksalt antiferromagnet MnO which undergoes a magnetostriction-driven rhombohedral distortion at the Néel temperature TN = 118 K. Above TN ...
Achieving ultra-low and -uniform residual magnetic fields in a very large magnetically shielded room for fundamental physics experiments
n2EDM is the current state of the art experiment carrying out a high-precision search for an electric dipole moment of the neutron at the ultra-cold neutron source of PSI. In order to reach it’s incredible precision of 10-27 e cm, a stable and uniform magnetic environment is critical. Thus, shielding the experiment from external magnetic flux and preparing a pristine magnetic environment is crucial. To achieve this, n2EDM uses both passive and active magnetic shielding components. External, or residual, magnetic field contributions must be near-zero, and can be achieved via “degaussing” the experiment’s passive magnetic shielding. Degaussing reduces, ideally “erases”, the residual magnetization of a material. In this work, we greatly improved the degaussing procedure of n2EDM, reducing the residual magnetic field by a factor of two, improving its uniformity, and all while taking less time and dissipating less heat.
With the discovery of a golden miniature box lock, an extraordinary and unique archaeological find was made in north-western Germany by a licensed detectorist.
The object represents an extremely reduced and valuable version of the provincial Roman box locks. These everyday objects were in general significantly larger and normally made either of iron, iron with silver or bronze bands or bronze.