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A glass system of composition 3As2O3-37PbO-(60-x) P2O5-xWO3 (0≤x≤ 5 mol%) was synthesized using a conventional melt-quenching method. The characteristics of the optical properties were studied in detail by measuring the absorbance and transmittance spectra of the synthesized glass. The indirect optical band gap decreased from 4.55 eV to 4.33 eV, while the direct band gap decreased from 4.88 eV to 4.76 eV. The Urbach energy varied between 0.55 eV and 0.42 eV. The results obtained for the optical energy band gap and the refractive index demonstrated a slight increase with an increase in tungsten ions in the prepared samples. Basicity, electronegativity, polarizability, metallization, and physical characteristics were estimated based on the obtained results. The refractive index and optical band gap were estimated theoretically by determining the optical basicity and molar refractivity. The half-value layer (HVL) and mean free path (MFP) were estimated and were found to decrease with an increase in tungstate ions in the fabricated glasses. The electron number density (Neff) and effective conductivity (Ceff) were determined as follows: (Neff, Ceff)W0% < (Neff, Ceff)W1% < (Neff, Ceff)W2% < (Neff, Ceff)W3% < (Neff, Ceff)W5%. Our findings confirmed that the PPA glass containing W ions could provide a superior material for use as a gamma attenuation shield.

Porous materials are very promising for the development of cost- and energy-efficient separation processes, such as for the purification of ethylene from ethylene/ethane mixture—an important but currently challenging industrial process. Here we report a microporous hydrogen-bonded organic framework that takes up ethylene with very good selectivity over ethane through a gating mechanism. The material consists of tetracyano-bicarbazole building blocks held together through intermolecular CN···H–C hydrogen bonding interactions, and forms as a threefold-interpenetrated framework with pores of suitable size for the selective capture of ethylene. The hydrogen-bonded organic framework exhibits a gating mechanism in which the threshold pressure required for guest uptake varies with the temperature. Ethylene/ethane separation is validated by breakthrough experiments with high purity of ethylene (99.1%) at 333 K. Hydrogen-bonded organic frameworks are usually not robust, yet this material was stable under harsh conditions, including exposure to strong acidity, basicity and a variety of highly polar solvents.Porous materials are promising candidates for the cost- and energy-efficient separation of ethylene and ethane from gas mixtures: an important but challenging industrial process. Now, a hydrogen-bonded organic framework has been reported that is stable under harsh conditions and can take up ethylene at practical temperatures—with very high selectivity over ethane—through a gating mechanism.

Applied magnetic fields induce a field in any compound with unpaired electrons. However, for the induced field to persist once the applied field is gone, the electrons must be configured to manifest orbital angular momentum. Generally, the influence of ligands severely restricts that property in transition metal complexes. Bunting et al. now show that a cobalt ion is just barely affected by two linearly coordinated carbon ligands and, as such, exhibits maximal orbital angular momentum. Although its magnetic properties mainly pertain at very low temperature, its structure offers a more general design principle. Science , this issue p. eaat7319 Magnetic properties arise in a cobalt ion because the influence of two linearly coordinated carbon ligands is unusually weak. Orbital angular momentum is a prerequisite for magnetic anisotropy, although in transition metal complexes it is typically quenched by the ligand field. By reducing the basicity of the carbon donor atoms in a pair of alkyl ligands, we synthesized a cobalt(II) dialkyl complex, Co(C(SiMe 2 ONaph) 3 ) 2 (where Me is methyl and Naph is a naphthyl group), wherein the ligand field is sufficiently weak that interelectron repulsion and spin-orbit coupling play a dominant role in determining the electronic ground state. Assignment of a non-Aufbau (d x 2 –y 2 , d xy ) 3 (d xz , d yz ) 3 (d z 2 ) 1 electron configuration is supported by dc magnetic susceptibility data, experimental charge density maps, and ab initio calculations. Variable-field far-infrared spectroscopy and ac magnetic susceptibility measurements further reveal slow magnetic relaxation via a 450–wave number magnetic excited state.

Glasses of chemical compositions 3As 2 O 3 -37PbO- (60-x)P 2 O 5 - xV 2 O 5 (x = 0, 0.5, 1, 2, 4 and 5 mol%) are fabricated by traditional melt-quenching technique. The optical features are considered depending on measuring the absorption and transmission of the fabricated glasses. The indirect optical band gap varied between 4.48 and 3.11 eV, while the direct ones varied from 4.61 to 3.61 eV. Urbach energies were changed from 0.193 to 0.335 eV. Based on the obtained values of band gap, the refractive index was found to be increase with increase vanadium ions in the present glass and varies from 2.032 to 2.380. Basicity, polarizability, electronegativity and some physical constants are determined depending on experimental results. Also, the refractive index and optical band gap are calculated depending on the theoretical optical basicity and molar refractivity. Values of the optical basicity were varied from 1.11 to 1.31 with varying vanadium content from zero to 5 mol%. Static dielectric constant for the favricated glasses was varied from 4.72 to 8.94, while cohesive energy was varied from 1.37 to 1.68 eV/atom. Half value layer (HVL) and mean free path (MFP) were followed the trend: (HVL, MFP) V0%  > (HVL, MFP) V0.5%  > (HVL, MFP) V1%  > (HVL, MFP) V2%  > (HVL, MFP) V3%  > (HVL, MFP) V5% . The electron number density (N eff ) and effective conductivity (C eff ) were followed the trend: (N eff , C eff ) V0%  < (N eff , C eff ) V0.5%  < (N eff , C eff ) V1%  < (N eff , C eff ) V2%  < (N eff , C eff ) V3%  < (N eff , C eff ) V5% .

The elimination of specific contaminants from competitors poses a significant challenge. Rather than relying on a single direct interaction, the cooperation of multiple functionalities is an emerging strategy for adsorbents design to achieve the required affinity. Here, we describe that the interaction with the target species can be altered by modifying the local environment of the direct contact site, as demonstrated by manipulating the affinity of pyridinium-based anion nanotraps toward pertechnetate. Systematic control of the substituent effect allows the resulting anion nanotraps to combine multiple features, overcoming the long-term challenge of TcO 4 − segregation under extreme conditions of super acidity and basicity, strong irradiation field, and high ionic strength. The top material exhibits the highest sorption capacity together with record-high extraction efficiencies after a single treatment from conditions relevant to the used nuclear fuel (Hanford tank wastes, 95%) and legacy nuclear wastes (Savannah River Sites, 80%) among materials reported thus far. The elimination of specific contaminants from high concentrations of competitors poses a significant challenge. Here the authors find that modifying the local environment of the direct contact site alters the interaction of a pyridinium-based anion nanotrap with pertechnetate.

Single-atom site (SA) catalysts on N-doped carbon (CN) materials exhibit prominent performance for their active sites being M-N x . Due to the commonly random doping behaviors of N species in these CN, it is a tough issue to finely regulate their doping types and clarify their effect on the catalytic property of such catalysts. Herein, we report that the N-doping type in CN can be dominated as pyrrolic-N and pyridinic-N respectively through compounding with different metal oxides. It is found that the proportion of distinct doped N species in CN depends on the acidity and basicity of compounded metal oxide host. Owing to the coordination by pyrrolic-N, the SA Cu catalyst displays an enhanced activity (two-fold) for transfer hydrogenation of quinoline to access the valuable molecule tetrahydroquinoline with a good selectivity (99%) under mild conditions. The higher electron density of SA Cu species induced by the predominate pyrrolic-N coordination benefits the hydrogen transfer process and reduces the energy barrier of the hydrogenation pathway, which accounts for the improved catalytic effeciency.

While platinum has hitherto been the element of choice for catalysing oxygen electroreduction in acidic polymer fuel cells, tremendous progress has been reported for pyrolysed Fe–N–C materials. However, the structure of their active sites has remained elusive, delaying further advance. Here, we synthesized Fe–N–C materials quasi-free of crystallographic iron structures after argon or ammonia pyrolysis. These materials exhibit nearly identical Mössbauer spectra and identical X-ray absorption near-edge spectroscopy (XANES) spectra, revealing the same Fe-centred moieties. However, the much higher activity and basicity of NH 3 -pyrolysed Fe–N–C materials demonstrates that the turnover frequency of Fe-centred moieties depends on the physico-chemical properties of the support. Following a thorough XANES analysis, the detailed structures of two FeN 4 porphyrinic architectures with different O 2 adsorption modes were then identified. These porphyrinic moieties are not easily integrated in graphene sheets, in contrast with Fe-centred moieties assumed hitherto for pyrolysed Fe–N–C materials. These new insights open the path to bottom-up synthesis approaches and studies on site–support interactions. Although Fe–N–C materials are promising catalysts for oxygen electroreduction in polymer fuel cells, the structure of their active sites is unclear. Quantitative analysis of Fe–N–C now reveals the existence of porphyrin-like FeN 4 C 12 moieties.

In this study, a series of nickels supported on gamma alumina with a metal dosage ranging from 0.5 to 3 wt.% were prepared and employed as the catalysts. The effect of nickel dosage on material properties, reaction performance, and catalyst deactivation was investigated. At a low dosage, the nickel-free having low metal-support interaction contributed significantly to the total active site. The basicity of the material was enhanced along with the increase in nickel loading. The presence of active metal showed a great impact at the beginning leading to big improvements in feedstock conversion. However, beyond a nickel dosage of 2 wt.%, further additions did not noticeably influence the reaction performance. Regarding catalyst deactivation, different carbon species were observed on catalyst surface, depending on the nickel dosage. Catalysts with less than 2 wt.% nickel exhibited amorphous carbon as the dominant morphology on the spent catalyst. In contrast, catalysts with 2Ni/Al 2 O 3 and 3Ni/Al 2 O 3 compositions showed graphitic carbon as the main side product. These findings provide insights into the relationship between nickel dosage, catalyst properties, and catalytic performance in methane dry reforming. By understanding the effects of nickel loading on material properties and reaction behavior, researchers can optimize catalyst design and develop more efficient and stable catalysts for sustainable syngas production.

Syngas, a mixture of carbon monoxide and hydrogen, is widely used in electricity, synthetic chemicals, and fuels productions. Syngas can be obtained from a chemical reaction between methane and carbon dioxide that are commonly found in biogas. In this study, a simulated mixture of biogas containing CH 4 :CO 2  = 1:1 (mol/mol) was used as the feedstock. Different nickel-based catalysts supported on TiO 2 , MgO, KIT-6, and Al 2 O 3 have been prepared through the dry impregnation method with a fixed Ni dosage of 10 wt%. All samples were characterized by modern techniques including XRD, BET, H 2 -TPR, CO 2 -TPD, TPO, and TEM. It was found that the metal-support interaction played a critical role in metal dispersibility and reducibility of catalyst precursors. During the methane dry reforming, catalyst basicity is a crucial factor facilitating the adsorption and activation of carbon dioxide. The highest activity was achieved over 10Ni/Al 2 O 3 with the methane conversion of 73.2% and carbon dioxide conversion of 86.9%. Furthermore, the effects of support properties on the catalyst stability were studied. Nature of support especially basicity plays an important role on the deposition of carbon over the active sites. The Ni/Al 2 O 3 with good nickel dispersibility, affordable metal-support interaction, reasonable basicity was reported the most stable without any significant deactivation after 6 h reaction. Finally, the catalyst design strategy for the DRM was proposed.

Development of large-scale alkaline seawater electrolysis requires robust and corrosion-resistant anodes. Here we propose engineering NiFe layered double hydroxide (LDH)-based anodes by incorporating a series of anions into the LDH interlayers. The most optimal NiFe LDH anode with intercalated phosphates demonstrates stable operation at a high current density of 1.0 A cm −2 for over 1000 hours in a 2 W-scale alkaline seawater electrolyzer (ASWE). Fundamental studies indicate that the basicity, indicated by p K a values, of the intercalated anions in NiFe LDH governs its oxygen evolution reaction activity and corrosion resistance. Highly basic anions (i.e., phosphates) securely anchor Fe sites and facilitate proton transfer to boost both durability and activity. Notably, we demonstrate the proof-of-concept for the NiFe anode in an industrial 1 kW-scale ASWE stack (1,081.2 cm 2 anode area in total). This unit achieves a stable operating current density of 0.5 A cm −2 at about 2.0 V, twice that of the commercial alkaline pure water electrolyzer, contributing to an economically competitive hydrogen production cost of US$ 1.96 kg H2 −1 . Large-scale alkaline seawater electrolysis demands robust anodes for efficient hydrogen production. Here, the authors report a NiFe layered double hydroxide anode with intercalated phosphates, achieving stable performance at 1.0 A cm −2 for over 1,000 hours, offering improved durability and activity.