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Thermal degradation is a leading cause of automotive catalyst deactivation. Because high-entropy oxides are uniquely stabilized at high temperatures via an increase in configurational entropy, these materials may offer new mechanisms for preventing the thermal deactivation of precious metal catalysts. In this work, we evaluated platinum loaded on simple and high-entropy aluminate spinels (MAl2O4, where M = Co, Cu, Mg, Ni, or mixtures thereof) in carbon monoxide oxidation before and after aging at 800 °C. Pt supported on all simple spinels showed significant deactivation after thermal aging compared to the fresh samples, with T90 increasing by at least 60 °C. However, Pt on high-entropy spinels had nearly the same or better activity after aging, with T90 increasing by only 6 °C at most. During aging and reduction, copper exsolved from the spinel supports and alloyed with platinum. This interaction promoted low temperature oxidation activity, presumably through weakened CO binding, but did not prevent deactivation. On the other hand, Co, Mg, and Ni constituents promoted stronger CO bonding, as evidenced by apparent negative order kinetics and poor activity at low temperatures. High-entropy spinels, containing a variety of active metals, displayed synergetic reactant adsorption capacity and cooperative effects with supported platinum particles, which collectively prevented thermal deactivation. [ABSTRACT FROM AUTHOR]

OBJECTIVE: Despite evidence that continuous glucose monitoring (CGM) use is associated with lower HbA1c among children with type 1 diabetes, uptake of this technology remains lower among those with difficulty accessing health care, including those from lower socioeconomic status backgrounds and racial and ethnic minorities. In this study, we sought to explore the impact of rural location in use of CGM technology to guide patient and provider decision making. RESEARCH DESIGN AND METHODS: In this retrospective study of electronic health record demographic and visits data from a single diabetes program from 1 January 2018 through 31 December 2021, we compared the odds of completing a visit with (+) and without (−) CGM interpretation between rural-urban commuting area (RUCA) designations. RESULTS: Among the 13,645 visits completed by 2,008 patients with type 1 diabetes younger than age 18 years, we found children living in small rural towns had 31% lower odds (6.3% of CGM+ visits, 8.6% of CGM− visits; adjusted odds ratio [aOR] 0.69, 95% CI 0.51–0.94) and those living in isolated rural towns had 49% lower odds (2.0% of CGM+ visits, 3.4% of CGM− visits; aOR 0.51, 95% CI 0.28–0.92) of completing a CGM-billed clinic visit compared with those living in urban areas (70.0% of CGM+ visits, 67.2% of CGM− visits). We also found significant differences in CGM-billed visits by neighborhood deprivation as well as race/ethnicity and insurance payor. CONCLUSIONS: Geographic location presents a meaningful barrier to access to care for patients living with type 1 diabetes. Further work is needed to identify and address the needs of children and families living in rural areas to improve the care of these patients. [ABSTRACT FROM AUTHOR]

While single-atom catalysts (SACs) have attracted a lot of interest, the nature of the active sites in SACs remains elusive. Here the authors elucidate that depositing single atoms via high temperature synthesis leads to improved reducibility of lattice oxygen on CeO2 yielding low temperature reactivity of Pt catalysts in CO oxidation.

Bulk metallic glasses (BMGs) have successfully been used to replicate molds that are structured at the nano- and even atomic scale through thermoplastic forming (TPF), an ability that was speculated to be rooted in the glass’ featureless atomic structure. These previous demonstrations of atomically precise imprinting, however, were performed under conditions where mold atomic feature dimensions coincided with the unit cell size of constituents in the BMG. In order to evaluate if accurate atomic-scale replication is possible in general, i.e., independent of the accidental presence of favorable constituent size/feature size relationships, we have used Pt57.5Cu14.7Ni5.3P22.5 to replicate three different crystalline facets of LaAlO3 single crystals, each exposing distinct atomic step heights. We find that in all cases, the terraced surface termination can be copied with remarkable fidelity, corroborating that BMGs when thermoplastic formed are capable of adapting to any externally imposed confinement with sub-angstrom precision without being limited by factors related to the specifics of their internal structure. This unprecedented capability of quasi-limitless replication fidelity reveals that the deformation mechanism in the supercooled liquid state of BMGs is essentially homogeneous and suggests TPF of BMGs to be a versatile toolbox for atomic and precision nanoscale imprinting.

Understanding the fracture toughness of metallic glasses remains challenging. Here, the authors show that a fictive temperature controls an abrupt mechanical toughening transition in metallic glasses, and can explain the scatter in previously reported fracture toughness data.

The local structure of the metal single-atom site is closely related to the catalytic activity of metal single-atom catalysts (SACs). However, constructing SACs with homogeneous metal active sites is a challenge due to the surface heterogeneity of the conventional support. Herein, we prepared two Rh1/CeO2 SACs (0.5Rh1/r-CeO2 and 0.5Rh1/c-CeO2, respectively) using two shaped CeO2 (rod and cube) exposing different facets, i.e., CeO2 (111) and CeO2 (100). In CO oxidation reaction, the T100 of 0.5Rh1/r-CeO2 SACs is 120 °C, while the T100 of 0.5Rh1/c-CeO2 SACs is as high as 200 °C. Via in-situ CO diffuse reflectance infrared Fourier transform spectroscopy (CO-DRIFTS), we found that the proximity between OH group and Rh single atom on the plane surface plays an important role in the catalytic activity of Rh1/CeO2 SAC system in CO oxidation. The Rh single atom trapped at the CeO2 (111) crystal surface forms the Rh1(OH)adjacent species, which is not found on the CeO2 (100) crystal surface at room temperature. Furthermore, during CO oxidation, the OH group far from Rh single atom on the 0.5Rh1/c-CeO2 disappears and forms Rh1(OH)adjacent species when the temperature is above 150 °C. The formation of Rh1(OH)adjacentCO intermediate in the reaction is pivotal for the excellent catalytic activity, which explains the difference in the catalytic activity of Rh single atoms on two different CeO2 planes. The formed Rh1(OH)adjacent-O-Ce structure exhibits good stability in the reducing atmosphere, maintaining the Rh atomic dispersion after CO oxidation even when pre-reduced at high temperature of 500 °C. Density functional theory (DFT) calculations validate the unique activity and reaction path of the intermediate Rh1(OH)adjacentCO species formed. This work demonstrates that the proximity between metal single atom and hydroxyl can determine the formation of active intermediates to affect the catalytic performances in catalysis. [ABSTRACT FROM AUTHOR]

Abstract We used pulsed laser beam welding method to join Pd43Cu27Ni10P20 (at.%) bulk metallic glass and characterized the properties of the joint. Fusion zone and heat-affected zone in the weld joint can be maintained completely amorphous as confirmed by X-ray diffraction and differential scanning calorimetry. No visible defects were observed in the weld joint. Nanoindentation and bend tests were carried out to determine the mechanical properties of the weld joint. Fusion zone and heat-affected zone exhibit very similar elastic moduli and hardness when compared to the base material, and the weld joint shows high ductility in bending which is accomplished through the operation of multiple shear bands. Our results reveal that pulsed laser beam welding under appropriate processing parameters provides a practical viable method to join bulk metallic glasses.