Highly Active IrRuOx MnOx Electrocatalysts with Ultralow Anode PGM Demand in Proton Exchange Membrane Electrolyzers

Thrifting the rare iridium in proton exchange membrane water electrolyzer PEMWE anodes is an effective means to preempt undesired future iridium supply shortages aiding wider deployment of PEMWEs in coming years. This work explores a new family of MnOx supported IrOx and IrRuOx electrocatalysts for the acidic oxygen evolution reaction OER . Comprehensive ex situ and in situ characterization uncovers synthesis structure activity relationships of the OER materials with insight into the origin of their exceptional activity The MnOx support provides beneficial dispersion while the introduction of Ru into IrOx MnOx leads to a modulation of the chemical state of Ir coupled with a strong surface reconstruction. In half cell tests, IrRuOx MnOx reveals an Ir mass activity of 964.7 A gIr amp; 8722;1 at 1.53 VRHE, which is 36 times higher than that of the commercial IrO2 C IrO2 . It is also demonstrated that this promising catalytic OER activity translates into a realistic PEMWE performance. IrRuOx MnOx and IrOx MnOx thin catalyst layers are developed in low Ir loaded membrane electrode assemblies MEAs and an outstanding PEMWE cell performance is reported with cell voltages of 1.66 V at 2 A cm amp; 8722;2. This translates into a favorable Ir Ru platium group metal PGM demand of lt;0.05 gPGM kW amp; 8722;1 at 70 voltage efficiency, meeting a 2035 technical demand targe

Detection of polycyclic aromatic hydrocarbons, microplastic presence and characterization of microbial communities in the soil of touristic zones at Alqueva s edges Alentejo, Portugal

Environmental pollution is a growing concern. Here, we assessed the occurrence of two groups of persistent organic pollutants POPs polycyclic aromatic hydrocarbons PAHs and microplastics MPs and bacterial populations in the topsoil of three tourist spots located at the Alqueva s edges during 1 year, once per season. Soil chemical analysis revealed low content of total organic carbon, pH close to neutrality, and nitrogen and phosphorus levels consistent with acquisition of these nutrients only by atmospheric deposition. PAH s concentrations were in the range of ng kg, being significantly below the reference values for contaminated soils. Nevertheless, potentially carcinogenic PAHs, detected at all locations, raise ecotoxicological concerns. Polyamide, polyester, polystyrene, and styrene acrylonitrile resin MPs were found. Six bacterial phyla constitute the core microbiome in the three locations and include genera of bacteria reported as plastic degraders, such as Bacillus, Exiguobacterium, Paenibacillus, and Pseudomonas. The presence of POPs, even at low levels, in the soil at the edges of a water reservoir should be monitored. The identification of bacteria reported as plastic degraders in the soil, and previously in the water, is promising, and their ability to spontaneously ensure the detoxification of the ecosystem should be further investigate

Determination of the oxidation depths of ground granulated blast furnace slag containing cement pastes using Mn K edge X ray absorption near edge structure spectroscopy

The redox potential of the pore solution of hardened cements containing ground granulated blast furnace slag GGBFS affects reinforcement corrosion and immobilization of radioactive waste. Here, Mn K edge X ray absorption near edge structure XANES spectroscopy was applied to determine the depth profile of the oxidation state of manganese in hardened GGBFS containing cement pastes. Manganese was oxidized in the outer regions of some of the pastes, but the depth to which this occurred was not identical with the blue green white color change front , usually interpreted as indicating oxidation of sulfur species. For CEM III B, the color change of the material was gradual and thus unsuitable for a precise determination of the oxidation depth, while for the alkali activated slag, a distinct color change front was found, but full oxidation of manganese and sulfur had not occurred in the brighter region. Mn K edge XANES spectroscopy is thus a more reliable method than the determination of the visual color change front to follow the ingress of the oxidation fron

Impact of metallographic polishing on the RF properties of Niobium for SRF applications

The performance of superconducting radio frequency SRF cavities made of niobium is tied to the quality of their inner surfaces exposed to the radio frequency RF waves. Future superconducting particle accelerators, because of their dimensions or the unprecedented stringent technical requirements, require the development of innovative surface processing techniques to improve processing reliability and if possible ecological footprint and cost, compared to conventional chemical processes. Metallographic polishing MP has emerged as a promising polishing technology to address these challenges. Previous studies focused on the characterization of the processed material surface at room temperature in the absence of RF waves. However, the evaluation of material properties, such as surface resistance under RF, at cryogenic temperature has failed, primarily due to the unavailability of devices capable of achieving the necessary resolution in the nanohm range. To overcome this limitation, a quadrupole resonator QPR has been utilized. The RF results demonstrate that the MP polishing, developed to preserve a high quality niobium surface with very low surface resistance, is highly effective compared to conventional polishing. This conclusion is further supported by topography and microstructural analysis of the QPR top hat samples, which revealed the clear superiority of the metallographic approac

Synchrotron Radiation for Quantum Technology

In recent years, quantum technology has undergone transformative advancements, opening up unprecedented possibilities in computation, metrology, sensing, and communication and reshaping the landscape of scientific research. Based on superposition, interference, and entanglement of quantum states, quantum systems leverage the core principles of quantum mechanics to achieve performances that were once deemed impossible or computationally insurmountable by classical methods. However, the practical realization of devices hinges on the conservation of these quantum states and their precise manipulation, requiring materials engineering with atomic precision on many length scales a formidable challenge. Synchrotron light and free electron laser FEL facilities, widely employed across diverse scientific and engineering disciplines, provide important single techniques and suites of multimodal non destructive imaging and diagnostic tools to reveal electronic, structural, and morphological properties of matter on device level. This article delves into how these tools can help to unlock the potential of quantum device technologies, overcoming production barriers and paving the way for future breakthroughs. Moreover, the article presents quantum optics in the x ray regime using synchrotron and FEL light sources and addresses the potential of quantum computing for synchrotron radiation experiment

Magnetic circular dichroism in core level x ray photoelectron spectroscopy of altermagnetic RuO2 films

While ferromagnetism and antiferromagnetism are well established classes of magnetic order, a third class of collinear magnetic order, termed altermagnetism, has recently attracted scientific interest. We measured magnetic circular dichroism MCD in core level photoemission XPS at the Ru 2 amp; 8290; amp; 119901;3 2 and 2 amp; 8290; amp; 119901;1 2 core levels in epitaxial RuO2 amp; 8290; 110 TiO2 amp; 8290; 110 films using circularly polarized x rays at 6 keV, as well as x ray magnetic circular dichroism XMCD in resonant x ray absorption at the Ru M3,2 3 amp; 8290; amp; 119901;3 2 and 3 amp; 8290; amp; 119901;1 2 edges. Charge transfer multiplet calculations show that the MCD XPS and the XMCD can be explained by an altermagnetic locking of Ru magnetic moments and a distorted crystal field orientation. The distortion is caused by the epitaxial strain. The collinear magnetic moments in RuO2 occupy sublattice sites with distorted octahedral crystal fields that are rotated by 90 amp; 8728; with respect to each other. A change in the sign of the MCD XPS at different sample positions indicates the presence of altermagnetic domains with the size of around hundreds of micrometer

Theoretical Calculation of Finite Temperature X Ray Absorption Fine Structure Application to Sodium K Edge in NaCl

This study presents a comprehensive computational framework for reproducing the full X ray absorption fine structure XAFS through quantum chemical simulations. The near edge region is accurately captured using an efficient implementation of time dependent density functional perturbation theory applied to core excitations, while ab initio molecular dynamics provides essential sampling of core excitation energies and interatomic distance distributions for interpreting extended X ray absorption fine structure EXAFS features. Owing to the efficiency of the approach, the total spectrum can be decomposed into contributions from bulk, defective, and surface environments, which commonly coexist in experimental systems. The method ology is demonstrated for sodium at the Na K edge in NaCl, where the predicted spectra show good agreement with experi mental measurements on thin film samples. This strategy offers a practical route to generating chemically specific XAFS cross section data for elements and species that remain challenging to characterize experimentally, thereby enabling deeper insights into materials of technological importanc

Triplet Metallovinylidenes of Palladium and Platinum Based on a Chelating P Diazoalkene Ligand

Triplet carbenes featuring a metal adjacent to the carbene center metallocarbenes; R amp; 9472;C amp; 9472;M are an emerging class of diradicals within the field of reactive intermediates. Here, we report the synthesis of the first spectroscopically characterized triplet metallovinylidenes R amp; 9472;C amp; 8594;M; M Pt, Pd . The synthetic access is based on a rigid P C chelating diazoalkene ligand and its coordination to Pt and Pd. The C P chelating ligand geometrically constrains the R amp; 9472;C amp; 8594;M angle and inhibits free bending. Irradiation of the free diazoalkene ligand generates a triplet vinylidene, characterized by Q band electron paramagnetic resonance EPR spectroscopy. Irradiation of the metal coordination complexes Pt and Pd affords triplet metallovinylidenes, which were characterized at low temperatures including photochemically triggered in crystallo X ray diffraction. Combined FD FT THz EPR spectroscopy and SQUID measurements allowed the determination of the large triplet zero field splitting ZFS with D values of 124.5 cm amp; 8722;1 Pt and 8.0 cm amp; 8722;1 Pd in excellent agreement with the electronic structure obtained by high level quantum chemical calculation

High pressure synthesis and high performance half metallicity of quadruple perovskite oxide DyCu3Fe2Re2O12

The A and B site ordered quadruple perovskite oxide DyCu3 Fe 2 Re 2 O 12 with cubic Pn 3 symmetry was synthesized under high pressure and high temperature conditions. The material experiences a sharp long range ferrimagnetic transition arising from the strong superexchange antiferromagnetic interactions of Cu Re and Fe Re at a high Curie temperature TC amp; 8776; 660 K . Owing to the influence at lower temperatures of the antiferromagnetic ordering of the Dy3 occupying the A site, the susceptibility of DyCu3 Fe 2 Re 2 O 12 decreases continuously below 50 K, which is essentially different from that of the isostructural compound LaCu3 Fe 2 Re 2 O 12 . Moreover, in the presence of a magnetic field, the A site Dy3 spins are readily transformed into the ferromagnetic state from theantiferromagnetic ground state. Thus,the saturated magnetic moment of DyCu3 Fe 2 Re 2 O 12 is sharply enhanced from 7.0 amp; 956;B f.u. at 300 K to 14 amp; 956;B f.u. at 2 K by applying a magnetic field of 7 T. Theoretical calculations suggest that DyCu3 Fe 2 Re 2 O 12 is a half metallic ferrimagnet with a spin up band gap of approximately 2.0 eV. The combination of the high Curie temperature, wide half metallic energy gap, and large magnetic moment makes DyCu3 Fe 2 Re 2 O 12 promising for potential applications in advanced spintronic device