Tuning the electronic structure and SMSI by integrating trimetallic sites with defective ceria for the CO reduction reaction.

Heterogeneous catalysts have emerged as a potential key for closing the carbon cycle by converting carbon dioxide (CO) into value-added chemicals. In this work, we report a highly active and stable ceria (CeO)-based electronically tuned trimetallic catalyst for CO to CO conversion. A unique distribution of electron density between the defective ceria support and the trimetallic nanoparticles (of Ni, Cu, Zn) was established by creating the strong metal support interaction (SMSI) between them.

Mercury speciation and stable isotopes in emperor penguins: First evidence for biochemical demethylation of methylmercury to mercury-dithiolate and mercury-tetraselenolate complexes.

Apex marine predators, such as toothed whales and large petrels and albatrosses, ingest mercury (Hg) primarily in the form of methylmercury (MeHg) via prey consumption, which they detoxify as tiemannite (HgSe). However, it remains unclear how lower trophic level marine predators, termed mesopredators, with elevated Hg concentrations detoxify MeHg and what chemical species are formed. To address this need, we used high energy-resolution X-ray absorption near edge structure spectroscopy paired with nitrogen (N) and Hg stable isotopes to identify the chemical forms of Hg, Hg sources, and species-specific δHg isotopic values in emperor penguin, a mesopredator feeding primarily on Antarctic silverfish.

Ferromagnetic stability optimization via oxygen-vacancy control in single-atom Co/TiO nanostructures.

Oxygen vacancies and their correlation with the nanomagnetism and electronic structure are crucial for applications in dilute magnetic semiconductors design applications. Here, we report on cobalt single atom-incorporated titanium dioxide (TiO) monodispersed nanoparticles synthesized using a thermodynamic redistribution strategy. Using advanced synchrotron-based X-ray techniques and simulations, we find trivalent titanium is absent, indicating trivalent cations do not influence ferromagnetic (FM) stability.

Mechanism Behind the Enhanced Ferromagnetic Contributions Upon Ru Substitution in CaMnO from X-Ray Absorption Spectroscopies.

We have studied the local structure and electronic and magnetic properties of hybrid improper ferroelectric CaMnO upon Ru substitution at the Mn site by a combination of atomic-selective X-ray absorption spectroscopies in the soft and hard X-ray energy regimes. Ru substitution enhances the macroscopic ferromagnetic contributions, whose origin is here elucidated. In particular, soft X-ray magnetic circular dichroism (XMCD) data indicate that the spin moments of Mn and Ru are aligned in opposite directions, with the effective magnetic moments of Ru being about 1 order of magnitude smaller than for Mn.