Catalytic Water Electrolysis by Co-Cu-W Mixed Metal Oxides: Insights from X-ray Absorption Spectroelectrochemistry.

Mixed metal oxides (MMOs) are a promising class of electrocatalysts for the oxygen evolution reaction (OER) and hydrogen evolution reaction (HER). Despite their importance for sustainable energy schemes, our understanding of relevant reaction pathways, catalytically active sites, and synergistic effects is rather limited. Here, we applied synchrotron-based X-ray absorption spectroscopy (XAS) to explore the evolution of the amorphous Co-Cu-W MMO electrocatalyst, shown previously to be an efficient bifunctional OER and HER catalyst for water splitting.

New Scalable Sulfur Cathode Containing Specifically Designed Polysulfide Adsorbing Materials.

Because of its considerable theoretical specific capacity and energy density, lithium-sulfur battery technology holds great potential to replace lithium-ion battery technology. However, a versatile, low-cost, and easily scalable bulk synthesis method is essential for translating bench-level development to large-scale production. This paper reports the design and synthesis of a new scalable sulfur cathode, S@CNT/PANI/PPyNT/TiO (BTX).

Structural Distortion in the Wadsley-Roth Niobium Molybdenum Oxide Phase Triggering Extraordinarily Stable Battery Performance.

Wadsley-Roth niobium oxide phases have attracted extensive research interest recently as promising battery anodes. We have synthesized the niobium-molybdenum oxide shear phase (Nb, Mo) O with superior electrochemical Li-ion storage performance, including an ultralong cycling lifespan of at least 15000 cycles. During electrochemical cycling, a reversible single-phase solid-solution reaction with lithiated intermediate solid solutions is demonstrated using in situ X-ray diffraction, with the valence and short-range structural changes of the electrode probed by in situ Nb and Mo K-edge X-ray absorption spectroscopy.

Two-Year Follow-Up of Chronic Ischemic Heart Disease Patients in a Specialized Center in Brazil.

The incidence of cardiovascular events in patients with chronic ischemic heart disease (CIHD) may vary significantly among countries. Although populous, Brazil is often underrepresented in international records. This study aimed to describe the quality of care and the two-year incidence of cardiovascular events and associated prognostic factors in CIHD patients in a tertiary public health care center in Brazil.

Chronic troponin elevation assessed by myocardial T1 mapping in patients with stable coronary artery disease.

Background: Cardiac troponin detected with sensitive assays can be chronically elevated, in the absence of unstable coronary syndromes. In patients with chronic coronary artery disease, clinically silent ischemic episodes may cause chronic troponin release. T1 mapping is a cardiovascular magnetic resonance technique useful in quantitative cardiac tissue characterization.

Engineering a Self-Grown TiO /Ti-MOF Heterojunction with Selectively Anchored High-Density Pt Single-Atomic Cocatalysts for Efficient Visible-Light-Driven Hydrogen Evolution.

A photocatalyst TiO /Ti-BPDC-Pt is developed with a self-grown TiO /Ti-metal-organic framework (MOF) heterojunction, i.e., TiO /Ti-BPDC, and selectively anchored high-density Pt single-atomic cocatalysts on Ti-BPDC for photocatalytic hydrogen evolution.

Bottom-up evolution of perovskite clusters into high-activity rhodium nanoparticles toward alkaline hydrogen evolution.

Self-reconstruction has been considered an efficient means to prepare efficient electrocatalysts in various energy transformation process for bond activation and breaking. However, developing nano-sized electrocatalysts through complete in-situ reconstruction with improved activity remains challenging. Herein, we report a bottom-up evolution route of electrochemically reducing CsRhI halide-perovskite clusters on N-doped carbon to prepare ultrafine Rh nanoparticles (~2.

Entrapped Molecule-Like Europium-Oxide Clusters in Zinc Oxide with Nearly Unaffected Host Structure.

Nanocrystalline ZnO sponges doped with 5 mol% EuO are obtained by heating metal-salt complex based precursor pastes at 200-900 °C for 3 min. X-ray diffraction, transmission electron microscopy, and extended X-ray absorption fine structure (EXAFS) show that phase separation into ZnO:Eu and c-Eu O takes place upon heating at 700 °C or higher. The unit cell of the clean oxide made at 600 °C shows only ≈0.

Excitation-Dependent Photoluminescence of BaZrO:Eu Crystals.

The elucidation of local structure, excitation-dependent spectroscopy, and defect engineering in lanthanide ion-doped phosphors was a focal point of research. In this work, we have studied Eu-doped BaZrO (BZOE) submicron crystals that were synthesized by a molten salt method. The BZOE crystals show orange-red emission tunability under the host and dopant excitations at 279 nm and 395 nm, respectively, and the difference is determined in terms of the asymmetry ratio, Stark splitting, and intensity of the uncommon D → F transition.

Operando Elucidation of Electrocatalytic and Redox Mechanisms on a 2D Metal Organic Framework Catalyst for Efficient Electrosynthesis of Hydrogen Peroxide in Neutral Media.

The practical electrosynthesis of hydrogen peroxide (HO) is hindered by the lack of inexpensive and efficient catalysts for the two-electron oxygen reduction reaction (2e ORR) in neutral electrolytes. Here, we show that NiHAB (HAB = hexaaminobenzene), a two-dimensional metal organic framework (MOF), is a selective and active 2e ORR catalyst in buffered neutral electrolytes with a linker-based redox feature that dynamically affects the ORR behaviors. Rotating ring-disk electrode measurements reveal that NiHAB has high selectivity for 2e ORR (>80% at 0.

Charge Transfer-Triggered Bi Near-Infrared Emission in YTiO for Dual-Mode Temperature Sensing.

Trivalent bismuth is a popular main group ion showing versatile luminescent behaviors in a broad spectral range from ultraviolet to visible, but barely in the near-infrared (NIR) region. In this study, we have observed unexpected NIR emission at ∼744 nm in a Bi-doped pyrochlore, YTiO (YTOB). Our first-principles electronic structure calculation and analysis of the Bi local structure via extended X-ray absorption fine structure indicate that only Bi species appears in YTOB and it has a similar local environment to that of Y.

Gold-like activity copper-like selectivity of heteroatomic transition metal carbides for electrocatalytic carbon dioxide reduction reaction.

An overarching challenge of the electrochemical carbon dioxide reduction reaction (eCORR) is finding an earth-abundant, highly active catalyst that selectively produces hydrocarbons at relatively low overpotentials. Here, we report the eCORR performance of two-dimensional transition metal carbide class of materials. Our results indicate a maximum methane (CH) current density of -421.

Antiferromagnetic Order and Spin-Canting Transition in the Corrugated Square Net Compound Cu(TeO)(SO)·HO.

Strongly correlated electrons in layered perovskite structures have been the birthplace of high-temperature superconductivity, spin liquids, and quantum criticality. Specifically, the cuprate materials with layered structures made of corner-sharing square-planar CuO units have been intensely studied due to their Mott insulating ground state, which leads to high-temperature superconductivity upon doping. Identifying new compounds with similar lattice and electronic structures has become a challenge in solid-state chemistry.

High-Pressure Synthesis of Double Perovskite BaNiIrO: In Search of a Ferromagnetic Insulator.

Double perovskite oxides with d-d electronic configurations are expected to be ferromagnetic from the Goodenough-Kanamori rules, such as ferromagnetic LaNiMnO. In search of new ferromagnetic insulators, double perovskite BaNiIrO was successfully synthesized by high-pressure and high-temperature methods (8 GPa and 1573 K). BaNiIrO crystallizes in a cubic double perovskite structure (space group: 3̅), with an ordered arrangement of NiO and IrO octahedra.

Kinetically Stable Oxide Overlayers on Mo P Nanoparticles Enabling Lithium-Air Batteries with Low Overpotentials and Long Cycle Life.

The main drawbacks of today's state-of-the-art lithium-air (Li-air) batteries are their low energy efficiency and limited cycle life due to the lack of earth-abundant cathode catalysts that can drive both oxygen reduction and evolution reactions (ORR and OER) at high rates at thermodynamic potentials. Here, inexpensive trimolybdenum phosphide (Mo P) nanoparticles with an exceptional activity-ORR and OER current densities of 7.21 and 6.

Dual-Metal Interbonding as the Chemical Facilitator for Single-Atom Dispersions.

Atomically dispersed catalysts, with maximized atom utilization of expensive metal components and relatively stable ligand structures, offer high reactivity and selectivity. However, the formation of atomic-scale metals without aggregation remains a formidable challenge due to thermodynamic stabilization driving forces. Here, a top-down process is presented that starts from iron nanoparticles, using dual-metal interbonds (RhFe bonding) as a chemical facilitator to spontaneously convert Fe nanoparticles to single atoms at low temperatures.

Spontaneous redox continuum reveals sequestered technetium clusters and retarded mineral transformation of iron.

The sequestration of metal ions into the crystal structure of minerals is common in nature. To date, the incorporation of technetium(IV) into iron minerals has been studied predominantly for systems under carefully controlled anaerobic conditions. Mechanisms of the transformation of iron phases leading to incorporation of technetium(IV) under aerobic conditions remain poorly understood.

Oxygen Functionalized Copper Nanoparticles for Solar-Driven Conversion of Carbon Dioxide to Methane.

Solar conversion of carbon dioxide (CO) into hydrocarbon fuels offers a promising approach to fulfill the world's ever-increasing energy demands in a sustainable way. However, a highly active catalyst that can also tune the selectivity toward desired products must be developed for an effective process. Here, we present oxygen functionalized copper (OFn-Cu) nanoparticles as a highly active and methane (CH) selective catalyst for the electrocatalytic CO reduction reaction.

Discovery of Anion Insertion Electrochemistry in Layered Hydroxide Nanomaterials.

Electrode materials which undergo anion insertion are a void in the materials innovation landscape and a missing link to energy efficient electrochemical desalination. In recent years layered hydroxides (LHs) have been studied for a range of electrochemical applications, but to date have not been considered as electrode materials for anion insertion electrochemistry. Here, we show reversible anion insertion in a LH for the first time using Co and Co-V layer hydroxides.

Evolution of the Local Structure within Chromophoric Mn-O Trigonal Bipyramids in YMnIn O with Composition.

We have investigated the local environment around Mn and In ions in YMnIn O chromophores to understand the origin of the intense blue color for small values of x in these solid solutions. While X-ray diffraction results provide an average description of the trigonal bipyramidal (TBP) units about Mn/In atoms with five oxygens surrounding the cation, the X-ray absorption near edge structure (XANES) as well as extended X-ray absorption fine structure (EXAFS) of these materials clearly suggest the presence of two different TBP environments, one of which is similar to MnO TBP in YMnO. EXAFS in conjunction with first-principles calculations show that replacing larger In ions by smaller Mn ones additionally gives rise to another TBP strongly distorted along the axial direction, expanding one of the axial Mn-O bonds by ∼11%.

Abnormal elevation of myocardial necrosis biomarkers after coronary artery bypass grafting without established myocardial infarction assessed by cardiac magnetic resonance.

Background: The diagnosis of peri-procedural myocardial infarction is complex, especially after the emergence of high-sensitivity markers of myocardial necrosis.

Methods: In this study, patients with normal baseline cardiac biomarkers and formal indication for elective on-pump coronary bypass surgery were evaluated. Electrocardiograms, cardiac biomarkers, and cardiac magnetic resonance imaging with late gadolinium enhancement were performed before and after procedures.

Myocardial injury in diabetic patients with multivessel coronary artery disease after revascularization interventions.

Background: Diabetic patients may be more susceptible to myocardial injury after coronary interventions. Thus, the aim of this study was to assess the release of cardiac biomarkers, CK-MB and troponin, and the findings of new late gadolinium enhancement (LGE) on cardiac magnetic resonance (CMR) in patients with type 2 diabetes mellitus after elective revascularization procedures for multivessel coronary artery disease (CAD).

Methods: Patients with multivessel CAD and preserved systolic ventricular function underwent either elective percutaneous coronary intervention (PCI), off-pump or on-pump bypass surgery (CABG).

Significant elevation of biomarkers of myocardial necrosis after coronary artery bypass grafting without myocardial infarction established assessed by cardiac magnetic resonance.

The release of myocardial necrosis biomarkers after off-pump coronary artery bypass grafting (OPCAB) frequently occurs. However, the correlation between biomarker release and the diagnosis of procedure-related myocardial infarction (MI) (type 5) has been controversial. This study aimed to evaluate the amount and pattern of cardiac biomarker release after elective OPCAB in patients without evidence of a new MI on cardiac magnetic resonance (CMR) imaging with late gadolinium enhancement (LGE).