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Operando Photoelectron Photoion Coincidence Spectroscopy to Detect Short-lived Intermediates in Catalysis
Get PDFUnderstanding the reaction mechanism is critical yet challenging in heterogeneous catalysis. Reactive intermediates, e.g., radicals and ketenes, are short-lived and often evade detection. In this review, we summarize recent developments with operando photoelectron photoion coincidence (PEPICO) spectroscopy as a versatile tool capable of detecting elusive intermediates. PEPICO combines the advantages of mass spectrometry and the isomer-selectivity of threshold photoelectron spectroscopy. Recent applications of PEPICO in understanding catalyst synthesis and catalytic reaction mechanisms involving gaseous and surface-confined radical and ketene chemistry will be summarized
Toward in silico Catalyst Optimization
Get PDFIn this minireview, we overview a computational pipeline developed within the framework of NCCR Catalysis that can be used to successfully reproduce the enantiomeric ratios of homogeneous catalytic reactions. At the core of this pipeline is the SCINE Molassembler module, a graph-based software that provides algorithms for molecular construction of all periodic table elements. With this pipeline, we are able to simultaneously functionalizenand generate ensembles of transition state conformers, which permits facile exploration of the influencenof various substituents on the overall enantiomeric ratio. This allows preconceived back-of-the-envelope designnmodels to be tested and subsequently refined by providing quick and reliable access to energetically low-lyingntransition states, which represents a key step in undertaking in silico catalyst optimization
Eliminating Flooding-related Issues in Electrochemical CO₂-to-CO Converters: Two Lines of Defense
Get PDFBy using silver (Ag) in nanostructured (nanowire, nanosphere, etc.) or thin-layer form as a catalyst for electrochemical CO2 reduction, very high CO-forming selectivity of almost 100% can be achieved. Supported by gas diffusion layers (GDLs), the reactant CO2 in the gas phase can approach and potentially access active Ag sites, which allows current densities in the range of a few hundred mA cm–2 to be reached. Yet, the stability of gas diffusion electrode (GDE) based electrochemical CO2-to-CO converters is far from perfect, and the activity of GDE cathodes, especially when operated at high current densities, often significantly decays during electrolyses after no more than a few hours. The primary reason of stability losses in GDE-based CO2-to-CO electrolysers is flooding: that is, the excess wetting of the GDE that prevents CO2 from reaching Ag catalytic sites. In the past years, the authors of this paper at Empa and at the University of Bern, cooperating with other partners of the National Competence Center for Research (NCCR) on Catalysis, took different approaches to overcome flooding. While opinions differ with regard to where the first line of defense in protecting GDEs from flooding should lie, a comparison of the recent results of the two groups gives unique insight into the nature of processes occurring in GDE cathodes used for CO2 electrolysis
Coupling of Dye Analysis and Compound Specific Radiocarbon (14C) Analysis (CSRA) in Heritage Sciences: FH HES Universities of Applied Sciences
No full textNatural organic dyes and pigments have been used for millennia to bring colour into our daily lives. Being sourced from a variety of natural sources, they form an extremely varied and large class of compounds, all of which retain the atmospheric 14CO2 of their year of growth. As such these compounds represent ideal candidates for radiocarbon (14C) dating, allowing the identification of or providing information towards the period in which the coloured artefact was created. However, up to now no such analysis has ever been conducted solely on organic colourants within an object. The complex nature of the samples and the sample size limitations with respect to precious and rare art artefacts requires innovative inter- and multidisciplinary approaches. Here we discuss preliminary results in the development of a compound-specific radiocarbon analysis (CSRA) methodology for the analysis of anthraquinone derived red dyes extracted from dyed wool yarns. The aim of this research project is to introduce new routes to date cultural heritage objects, in particular to overcome their intrinsic complexity through the development of CSRA strategies
Recent Progress of Remediating Heavy Metal Contaminated Soil Using Layered Double Hydroxides as Super-Stable Mineralizer
Get PDFHeavy metal contamination in soil, which is harmful to both ecosystem and mankind, has attracted worldwide attention from the academic and industrial communities. However, the most-widely used remediation technologies such as electrochemistry, elution, and phytoremediation. suffer from either secondary pollution, long cycle time or high cost. In contrast, in situ mineralization technology shows great potential due to its universality, durability and economical efficiency. As such, the development of mineralizers with both high efficiency and low-cost is the core of in situmineralization. In 2021, the concept of ‘Super-Stable Mineralization’ was proposed for the first time by Kong et al.[1] The layered double hydroxides (denoted as LDHs), with the unique host–guest intercalated structure and multiple interactions between the host laminate and the guest anions, are considered as an ideal class of materials for super-stable mineralization. In this review, we systematically summarize the application of LDHs in the treatment of heavy metal contaminated soil from the view of: 1) the structure–activity relationship of LDHs in in situ mineralization, 2) the advantages of LDHs in mineralizing heavy metals, 3) the scale-up preparation of LDHs-based mineralizers and 4) the practical application of LDHs in treating contaminated soil. At last, we highlight the challenges and opportunities for the rational design of LDH-based mineralizer in the future
Upcycling of Cereal Byproducts: A Sustainable Opportunity to Valorize Wasted Nutrients and Derive Bioactive Compounds for Humans and Animals Nutrition and Health
Get PDFWith the global population projected to reach close to 10 billion by 2050, the escalating demand for cereals such as wheat, rice, corn, oat, and barley places significant pressure on production systems. These systems are increasingly vulnerable to the adverse impacts of climate change, threatening global food security. This article emphasizes the critical need to address these challenges and explores strategies for sustainable foodproduction, focusing on the opportunities that the upcycling of cereal byproducts offers for human and animal nutrition and health
Comparison of Plasma Ionization- and Secondary Electrospray Ionization- High-resolution Mass Spectrometry for Real-time Breath Analysis
Get PDFReal-time breath analysis by high-resolution mass spectrometry (HRMS) is a promising method to noninvasively retrieve relevant biochemical information. In this work, we conducted a head-to-head comparison of two ionization techniques: Secondary electrospray ionization (SESI) and plasma ionization (PI), for the analysis of exhaled breath. Two commercially available SESI and PI sources were coupled to the same HRMS device to analyze breath of two healthy individuals in a longitudinal study. We analyzed 58 breath specimens in both platforms, leading to 2,209 and 2,296 features detected by SESI-HRMS and by PI-HRMS, respectively. 60% of all the mass spectral features were detected in both platforms. However, remarkable differences were noted in terms of the signal-to-noise ratio (S/N), whereby the median (interquartile range, IQR) S/N ratio for SESI-HRMS was 115 (IQR = 408), whereas for PI-HRMS it was 5 (IQR = 5). Differences in the mass spectral profiles for the same samples make the inter-comparability of both techniques problematic. Overall, we conclude that both techniques are excellent for real-time breath analysis because of the very rich mass spectral fingerprints. However, further work is needed to fully understand the exact metabolic insights one can gather using each of these platforms
Community Masks - from an Emergency Solution to an Innovation Booster for the Textile Industry
Get PDFThe COVID-19 pandemic resulted in shortages of personal protective equipment and medical devices in the initial phase. Agile small and medium-sized enterprises from regional textile industries reacted quickly. They delivered alternative products such as textile-based community masks in collaboration with industrial partners and research institutes from various sectors. The current mask materials and designs were further improved by integrating textiles with antiviral and antimicrobial properties and enhanced protection and comfort by novel textile/membrane combinations, key factors to increase the acceptance and compliance of mask wearing. The innocuity and sustainability of masks, as well as taking into account particular needs of vulnerable persons in our society, are new fields for textile-based innovations. These innovations developed for the next generation of facemasks have a high adaptability to other product segments, which make textiles an attractive material for hygienic applications and beyond
Recent Advancements in Development and Application of an Iron-based Shape Memory Alloy at Empa
Get PDFThe Fe-SMA developed at the Swiss Federal Laboratories for Materials Science and Technology (Empa) has an alloy composition of Fe–17Mn–5Si–10Cr–4Ni–1(V,C) and exhibits an excellent shape memory effect on heating at 160 °C or above. The shape memory effect feature equips Fe-SMA with a unique self-prestressing ability that can be exploited for many civil engineering applications. In addition to the self-prestressing ability, Fe-SMA has a high elastic modulus (165 GPa), low cost, and high machinability compared to the nickel and copper-based SMAs, which makes it more suitable for structural applications. The current work aims to provide an overview of the recent advancements in the research and development of Fe-SMA at Empa. To this end, the advancements related to the material development, applications of Fe-SMAs in prestressing reinforced concrete (RC) and metallic structures, and the introduction of Fe-SMA reinforcements to the market alongwith some recent field applications are presented. The paper concludes with an overview of the opportunities and challenges associated with using Fe-SMA reinforcements in civil infrastructure
The Emerging Potential of Advanced Targeted Mass Spectrometry to Become a Routine Tool for Protein Quantification in Biomedical Research
Get PDFMass spectrometry-based proteomics has become an indispensable tool for system-wide protein quantification in systems biology, biomedical research, and increasing for clinical applications. In particular, targeted mass spectrometry offers the most sensitive and reproducible quantitative detection of proteins, peptides and post-translational modifications of any currently applied mass spectrometry technique and is therefore ideally suited to generate high quality quantitative datasets. Despite these apparent advantages, targeted mass spectrometry is only slowly gaining popularity in academia and pharmaceutical industries, mainly due to the additional efforts in assay generation and manual data validation. However, with the increasing accumulation of mass spectrometry data, advances in deep learning spectral prediction for automated assay development, these obstacles can and will be considerably reduced in the near future. Here, we describe the latest technological developments in this field and discuss the emerging importance of targeted mass spectrometry for systems biology research and potential key roles in bridging biomedical discovery and clinical implementation.