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ALS Work Using Spectroscopy

These techniques are used to study the energies of particles that are emitted or absorbed by samples that are exposed to the light-source beam and are commonly used to determine the characteristics of chemical bonding and electron motion.

 

Scientists Uncover Surprising New Clues to Exotic Superconductors’ Superpowers

Researchers studied a model material (CeCoIn5) that mimics a cuprate superconductor that can be switched on and off using high magnetic fields. In chemical compositions where the superconductivity is strongest, the number of free electrons jumps, signifying a transition point. The researchers attributed this transition to the behavior of electrons associated with the cerium atoms. Read more »

A Photoelectrode Protection Scheme for Solar-Fuel Production

Microscopy, spectroscopy, and computational studies of a promising artificial-photosynthesis material led researchers to develop a model photoelectrochemical (PEC) cell with remarkable stability and longevity as it selectively converts sunlight and carbon dioxide into two promising sources of renewable fuels—ethylene and hydrogen. Read more »

Interlayer Coupling Drives Mysterious Phase Transition

Researchers found that a mysterious phase transition in an iron-based superconductor is driven by interactions between the material’s 2D layers. The results counter the assumption that interlayer coupling is negligible in such materials, suggesting instead that the interactions can be an effective way to tune superconductivity. Read more »PPT-icon-35 PDF-icon-35

Scientists Discover ‘Secret Sauce’ Behind Exotic Properties of New Quantum Material

Kagome metals have long mystified scientists for their ability to exhibit collective behavior when cooled below room temperature. A research team has discovered that the kagome electrons’ unusual synchronicity is due to another behavior known as an electronic singularity, or the Van Hove singularity, which involves the relationship between the electrons’ energy and velocity. Read more »

Revealing Lithium Metal’s Electronic Structure

Spectroscopy at the ALS and theoretical calculations at the Molecular Foundry revealed the intrinsic spectroscopic signature of lithium metal and explained the origin of previous contradictory reports. The findings provide a benchmark for further studies of lithium compounds towards batteries with higher capacity and energy density. Read more »PPT-icon-35 PDF-icon-35

Synthesis of new two-dimensional titanium carbonitride Ti2C0.5N0.5Tx MXene and its performance as an electrode material for sodium-ion battery

Researchers report on the synthesis and characterization of a new 2D carbonitride MXene, Ti2C0.5N0.5. They explore the performance of this new MXene as electrode materials for sodium-ion batteries (SIBs). It outperformed its carbide counterpart (i.e., Ti2C) and all the other reports for multilayer MXenes in SIBs, and it showed a stable electrochemical performance over 500 cycles. Read more »

New Device Advances Commercial Viability of Solar Fuels

A Berkeley Lab research team developed a new artificial photosynthesis device component that exhibits remarkable stability and longevity as it selectively converts sunlight and carbon dioxide into two promising sources of renewable fuels—ethylene and hydrogen. Read more »

Nanoscale Confinement of Photo-Injected Electrons at Hybrid Interfaces

Picosecond time-resolved x-ray photoemission spectroscopy provides real-time electron distributions of donors and acceptors in a prototypical bipyridyl-ZnO hybrid light harvesting system. The measurements show that photo-injected electrons remain localized within the defect-rich surface region of the nanoporous ZnO substrate, revealing a challenge for the extraction of free charge carriers. Read more »

Direct Observation of Surface-Bound Intermediates During Methanol Oxidation on Platinum Under Alkaline Conditions

A comprehensive mechanism for the methanol oxidation reaction (MOR) in alkaline media is presented, and it is shown that the MOR proceeds via two different pathways (via COad or H3C–Oad intermediates). The latter dominates the overall MOR current, suggesting that the H3C–Oad oxidation could be a viable pathway to accelerate the MOR in alkaline systems. Read more »

Interface Sensitivity in Electron/Ion Yield X-ray Absorption Spectroscopy: The TiO2–H2O Interface

To understand corrosion, energy storage, (electro)catalysis, etc., obtaining chemical information on the solid–liquid interface is crucial but remains extremely challenging. Here, x-ray absorption spectroscopy is used to study the solid–liquid interface between TiO2 and H2O. This result highlights the potential of electron-yield XAS to obtain chemical and structural information with a high sensitivity for the species at the electrode–electrolyte interface. Read more »