Powder Diffraction Research Articles

3D Confinement Stabilizes the Metastable Amorphous State of Antimony Nanoparticles - A New Material for Miniaturized Phase Change Memories?

The wet-chemical synthesis of 3D confined antimony nanoparticles (Sb-NP) at low and high temperatures is described. Using reaction conditions that are mild in temperature and strong in reducing power allows the synthesis of amorphous Sb-NP stabilized with organic ligands. Exchanging the organic ligand 1-octanethiol by iodide enabled to investigate the unusual strong stability of this metastable material through simultaneous thermal analysis combining differential scanning calorimetry and thermogravimetric analysis. Additionally, in situ high temperature powder x-ray diffraction (p-XRD) shows a significant increase in stabilization of the amorphous phase in comparison to thin layered, 1D confined Sb or bulk material. Further, it is shown with scattering-type scanning near-field optical microscopy (s-SNOM) experiments that the optical response of the different phases in Sb-NP make the distinctness of each phase possible. It is proposed that the Sb-NP introduced here can serve as a 3D-confined optically addressable nanomaterial of miniaturized phase change memory devices.

Prediction of Li-ion conductivity in Ca and Si co-doped LiZr2(PO4)3 using a denoising autoencoder for experimental data

All-solid-state batteries composed of inorganic materials are in high demand as power sources for electric vehicles owing to their improved safety, energy density, and overall lifespan. However, the low ionic conductivity of inorganic solid electrolytes has limited the performance and adoption of inorganic all-solid-state batteries. The solid electrolyte LiZr2(PO4)3 has attracted attention owing to its high Li-ion conductivity. The ionic conductivity of LiZr2(PO4)3 changes with the crystalline phase obtained, which varies based on composition control through elemental substitution and process conditions such as sintering temperature. Traditionally, optimizing such parameters and understanding their relationship to physical properties have relied on researcher experience and intuition. However, a recent use of a materials informatics approach utilizing machine learning shows promise for more efficient property optimization. This study proposes a deep learning model to correlate powder X-ray diffraction (XRD) profiles with the activation energy (Ea) for Li-ion conduction, thereby enhancing the interpretability of the measurement data. XRD profiles, which contain information on crystal structure, lattice strain, and particle size, were used as-is (i.e., without preprocessing) in the deep learning model. An attention mechanism was introduced to the deep learning model that focuses on XRD crystal-structure information and visualization of important factors embedded in the XRD profiles. The highlighted areas in the output of this model successfully predict LiZr2(PO4)3 phases with low Ea (high Li conductivity) and high Ea (low Li conductivity). Moving forward, this deep learning model can offer new insights to materials researchers, potentially contributing to the discovery of new solid electrolyte materials.

Bioavailability improvement by atomic layer coating: Fenofibrate a case study

Biopharmaceutical Classification Systems (BCS) class II drugs show poor solubility and high permeability in the body. Fenofibrate (FF) is a classic example of a BCS class II drug, used to treat high cholesterol and triglyceride (fat-like substances) levels in the blood. Atomic layer coating (ALC) is a surface engineering technology adapted from the semiconductor industry, where metal oxides are coated one atomic layer at a time over the active pharmaceutical ingredients (API) particles. ALC coating was proven to improve the processability, alter the hydrophilicity, improve the stability, and fine-tune the release of drugs. Herein, we report the intervention of ALC coating in enhancing the bioavailability of a poorly water-soluble drug (fenofibrate) in the animal model. The physical properties of uncoated fenofibrate were compared with those of zinc oxide-coated and silicon oxide-coated fenofibrate. Following the application of the coatings, the structural integrity (both chemical stability and solid-state stability) of the active pharmaceutical ingredient (API) remained uncompromised, as corroborated by 1H NMR and powder X-ray diffraction analyses. Notably, zinc oxide-coated fenofibrate exhibited favorable flow characteristics, whereas no discernible enhancement in flow behavior was observed for silicon oxide-coated fenofibrate. The results from contact angle measurements suggest that the silicon oxide-coated fenofibrate exhibits superior wetting behavior, as indicated by a contact angle nearing 0°. The application of ALC demonstrates an enhanced dissolution rate when compared to the uncoated active pharmaceutical ingredient (API) while leaving its equilibrium solubility unaffected. Coating the API with silicon oxide improves particle hydrophilicity and wetting properties, whereas zinc oxide coating aids in particle de-agglomeration, thereby enhancing their interaction with an aqueous medium. In vivo bioavailability studies conducted on rodents and larger animal (dog) models indicate a substantial increase in bioavailability (approximately 2 times) for the silicon oxide-coated API in comparison to the uncoated API, as determined by the area under the curve (AUC). Furthermore, the Cmax values for the silicon oxide-coated API also demonstrate a significant increase (approximately 3 times) over the uncoated API. Notably, an oral subacute toxicity study of ALC silicon-coated fenofibrate revealed no toxic effects attributable to the coating. This study underscores the potential of ALC in augmenting the bioavailability of BCS(II) drugs.

Structural disorder Triggered by small organic molecules Boosting δ-MnO2 cathode for Ultra‐Stable aqueous zinc ion batteries

The inferior cycling stability of MnO2-based cathodes, resulting from Mn dissolution and crystal structure transition during Zn-ion insertion/extraction, poses a significant challenge hindering their widespread adoption in aqueous zinc-ion batteries (AZIBs). To mitigate these issues, we propose an approach involving the incorporation of small organic molecules (methylformamide, dimethylformamide, and formamide) to modify the crystalline structure of MnO2. These molecules, characterized by their low orbital energy levels, facilitate the creation of energetically equivalent electron transfer pathways with the unoccupied eg orbitals in Mn4+, as evidenced by the DFT calculations. Furthermore, they modulate the electron cloud density of Mn-O and introduce structural disorder in the MnO2 crystalline lattice, thereby greatly enhancing the structural stability of the Mn-based cathode. In AZIBs tests, the MnO2/methylformamide (MO/NMF) cathode demonstrates a remarkable reversible specific capacity exceeding 270 mAh g−1 at 1 A g−1 and exceptional durability, exhibiting negligible capacity degradation after 2000 cycles at 3 A g−1. In-situ X-ray diffraction, neutron powder diffraction and high-angle annular dark-field scanning transmission electron microscopy analyses confirm the structure stability of MO/NMF during Zn-ion insertion/extraction, attributed to the NMF modification. Additionally, the electrochemical data indicate that modifications with dimethyl formamide and formamide also positively impact the electrochemical performance of the MnO2 cathode. This study offers valuable insights for the development of high-performance Mn-based cathodes.

Cerium-Organic Framework UiO-66(Ce) as a Support for Nanoparticulate Gold for Use in Oxidation Catalysis.

An optimised synthesis of the metal-organic framework (MOF) UiO-66(Ce) is reported using a modulator-free route, yielding ~5 g of material with high crystallinity and 22 % ligand defect. Two methods are developed for loading gold nanoparticles onto the MOF. The first uses a double-solvent method to introduce HAuCl4 onto UiO-66(Ce), followed by reduction under 5 % H2 in N2, while the second is a novel one-pot method where HAuCl4 is added to the synthesis mixture, forming Au nanoparticles within the pores of the UiO-66(Ce) during crystallisation. Analysis using powder X-ray diffraction (PXRD), nitrogen adsorption isotherms, transmission electron microscopy and small-angle X-ray scattering (SAXS) reveals that the two-step double-solvent method yields gold crystallites on the external surface of the MOF particles that are visible by PXRD. In contrast, the one-pot method forms smaller gold crystallites, with a distribution of sizes centred on ~4 nm diameter as seen by SAXS, with evidence from PXRD for the smallest particles being present within the MOF structure. The Au-loaded UiO-66(Ce) materials are evaluated for the catalytic oxidation of vanillyl alcohol to vanillin at 60 °C. Our findings indicate that incorporating Au nanoparticles via the one-pot synthesis method, enhances redox activity, achieving 43 % conversion and 90 % selectivity towards vanillin.

High contrast stimuli-responsive fluorescence emitters based on carbazole-cyanostilbene derivatives with aggregation induced emission properties

Due to the aggregation induced emission (AIE) materials exhibiting obvious fluorescent emission changes under the external stimuli of heat, solvent, force and so on, significant efforts have been directed toward developing AIE-active materials with high contrast stimuli-responsive fluorescence behaviors. Herein, three electron-donor(D)-electron-acceptor(A) and D-A-D type organic fluorescence emitters of Cz-DC-tBu, Cz-DC-CN and Cz-DC-OMe were facilely synthesized using carbazole group as D unit and cyano group as A unit. They showed typical AIE features and exhibited remarkable color changes under mechanical force and in different polarity solvents, respectively. The stimuli-responsive mechanism of the compounds were investigated by powder X-ray Diffraction (PXRD) and density functional theory calculations (DFT), which revealed that the mechanofluorochromic behaviors were associated with the molecular packing modes, and the solvatochromic effects were caused by the intramolecular charge-transfer transition (ICT) effect. Significantly, it was found that Cz-DC-tBu showed high contrast stimuli-responsive behaviors through adjusting the substituent groups on the cyanostilbene unit with CN, OMe, and tBu groups, respectively. This study provided a new strategy for the design of AIE-active stimuli-responsive fluorescence emitters, and made them possible using in stress sensors, chemical detection, memory storage, anti-counterfeiting applications.

Removal of heavy metals from aqueous solutions by adsorption on zeolites synthesized from aluminum saline slags

Three heavy metals (Cu2+, Cd2+ and Pb2+) were removed from aqueous solutions using zeolites prepared from saline slags, a very important waste generated during aluminum recycling. Zeolites were characterized by powder X-ray diffraction, thermal analysis, Fourier transform infrared spectroscopy, X-ray microfluorescence, element chemical analysis, nitrogen adsorption at −196 °C and electron microscopy. The textural and structural properties of X-type faujasite zeolite convert it in a promising adsorbent in aqueous streams. Removal of the heavy metals was evaluated in batch mode, studying the adsorbent dose, the initial concentration of the heavy metal, the selectivity of the solid in case of mixtures with various metal cations and the recyclability of the solid. The kinetic and equilibrium results were evaluated using both pseudo-first- and pseudo-second-order kinetics, and Langmuir, Freundlich and Toth equation isotherms for the equilibrium. The time needed to reach equilibrium was between 10 and 20 min. Faujasite was highly effective in removing Cu2+, Cd2+ and Pb2+ from aqueous solutions, much higher than analcime and pollucite, other two zeolites recently synthesized by us from aluminum slags, and used in this work for comparison purposes. The maximum adsorption capacity was 591 mg/g for Pb2+, 304 mg/g for Cu2+ and 279 mg/g for Cd2+.

Aqueous phase synthesis of 2-D copper nanosheets stabilized by organic moieties with enhanced photocatalytic and biological activity.

Copper nanosheets supported by organic ligands are significant for biological, electrical, and catalytic applications. The discovery that the coronavirus has a significantly reduced maximum survival period on copper surfaces has elevated the utility of copper nanomaterials. Here, we report a non-hazardous and inexpensive biological technique for forming copper nanosheets (Cu Nsts); synthesis of Cu Nsts has always been a challenge for researchers due to the significant problem of oxidation; in this research, we have successfully synthesized stable Cu Nsts by using Saussurea lappa root extract for the first time, the obtained Cu Nsts has a shiny black color with self-standing ability, the crystal structure of Cu nanosheets was determined using Powder X-ray diffraction (PXRD), Scanning electron microscopy (SEM) revealed that copper nanoparticles grow and aggregates to form Cu Nsts. The surface morphology of Cu Nsts is clear evidence of their synthesis. These nanosheets were very proficient in the deduction of harmful dye (methylene blue); within 105 minutes, the degradation capacity of Cu nanosheets for methylene blue reached 93.493%. This remarkable property of Cu Nsts as a photocatalyst gives potential application for removing dyes from industrial wastewater. Cu Nsts showed excellent antioxidant and antibacterial activity. The Cu Nsts demonstrated potent inhibitory zones against E. coli, with inhibition zones measuring 39 mm. This research lays the foundations for purifying wastewater from harmful dyes and bacteria.

Synthesis and characterization of silica-supported cobalt acylpyrazolone complex and its catalytic performance in ethylbenzene oxidation

A novel β-diketone-containing acylpyrazolone (2-(3-chlorophenyl)-3‑hydroxy-5-methyl-2,3-dihydro-1H-pyrazole-4-yl) (4-nitrophenyl) methanone [HLC] ligand and its cobalt complex [Co(HLC)2(H2O)2] were synthesized and characterized. A silica-supported cobalt complex was synthesized as a heterogeneous catalyst to investigate the cobalt complex's catalytic activity. The characterization techniques used for the synthesized compounds are CHN analysis, SC-XRD, FT-IR, TGA, DRS spectra, BET and BJH measurements, ICP-MS, XPS, powder XRD and SEM. Without any solvent, the cobalt complex catalytic impact on the oxidation of ethylbenzene was investigated with tert‑butyl hydroperoxide (70 % TBHP) as an oxidant. The catalyst exhibited good conversion (88 % conversion) and selectivity (83 % acetophenone) in the oxidation of ethylbenzene. The catalyst shows no leaching occurred under the reaction conditions because it is stable and reusable for further reaction.

Crystal structure and Hirshfeld surface analysis of pinaverium bromide dihydrate

In the present study, we have discovered and identified a new crystalline form of pinaverium bromide, pinaverium bromide dihydrate (C26H41BrNO4⋅Br⋅2H2O), whose single crystals can be obtained by recrystallization from a mixture of water and acetonitrile at room temperature. The obtained crystals were characterized by X-ray single-crystal diffraction, and their crystal structure was also solved based on X-ray single-crystal diffraction data. The results show that the final pinaverium bromide dihydrate model contains an asymmetric unit of one pinaverium bromide (C26H41Br2NO4) molecule and two water molecules that combine with the bromine ion through O–H⋯O and O–H⋯Br hydrogen bonds. Then, the adjacent pinaverium bromide dihydrates are linked by O–H⋯O, O–H⋯Br, and C–H⋯O hydrogen bonds. On the other hand, the experimentally obtained X-ray powder diffraction pattern is in good agreement with the simulated diffraction pattern from their single-crystal data, confirming the correctness of the crystal structure. Hirshfeld surface analysis was employed to understand and visualize the packing patterns, indicating that the H⋯H interaction is the main acting force in the crystal stacking of pinaverium bromide dihydrate.

Experimental and computational analysis of R152a hydrate-based desalination: A promising solution for hypersaline brine treatment

This study addressed the treatment of hypersaline brine, specifically solutions containing 5.0 wt% and 10.0 wt% NaCl, by exploring the use of 1,1-difluoroethane (C2H4F2, R152a) hydrate-based desalination (HBD). The thermodynamic stability of R152a hydrates under hypersaline conditions was experimentally measured and predicted utilizing the Hu-Lee-Sum correlation. Powder X-ray diffraction analysis confirmed that the crystal structure of R152a hydrates (structure I) remained unchanged under hypersaline brine conditions. Hydrate growth kinetics and desalination efficiency were investigated under various temperature driving forces (ΔT = 2 K, 3 K, and 5 K) to elucidate the impact of temperature variations on hydrate growth rates and salt removal capabilities. Elevated temperatures resulted in slower growth rates but yielded higher desalination efficiency. Furthermore, molecular dynamics simulations provided microscopic insights into the mechanisms underlying these observations. Molecular dynamics analyses of hydrate growth and ion diffusion demonstrated that at lower temperatures, ion movement slowed down, leading to more ions being trapped within the hydrates. Additionally, free energy calculations corroborated that Na+ ions were more easily removed than Cl- ions due to their lower free energy barriers. This study highlights the potential of R152a HBD as a sustainable solution for hypersaline brine treatment, emphasizing the necessity for further optimization and development to fully realize its practical applications.

Effect of solvent in the solvothermal synthesis of nickel(II)-terephthalate complex

This research aims to replace the use of dimethylformamide (DMF) with a greener solvent in the solvothermal synthesis of nickel(II)-terephthalate complex. Effect of solvent on the crystallinity degree, thermal stability, and band gap energy of the synthesized complex are also studied. The synthesis was carried out using solvothermal method at 150 0C for 10 hours with a Ni(II) : terephthalate acid mol ratio of 1:1 in several H2O:DMF solvent compositions (1:0; 1:1; and 0:1). The precipitated products underwent characterization using ATR-IR, P-XRD, SEM, TGA, Surface Area Analyzer, and UV-DRS. Findings revealed the successful formation of the Ni(II)-terephthalate complex using three different solvent compositions (H2O/DMF = 1:0, 1:1, and 0:1). This suggests that the complex can be synthesized using more environmentally friendly solvents, potentially reducing or substituting the use of DMF solvent. However, the solvent affects the characteristics of the synthesized complex, in which green block microcrystalline solid was obtained when using water as the solvent, meanwhile green aggregates with lower crystallinity degree was precipitated out when using DMF or H2O-DMF. The Ni(II)-terephthalate complexes obtained from the H2O and H2O-DMF solvents are different to that of from the DMF solvent, but they both has identical powder diffraction pattern with previously reported compound of [Ni3(OH)2(C8H4O4)2(H2O)4].2H2O. Furthermore, the use of water as the solvent increase the crystallinity degree and thermal stability of the complex but the band gap energy of the synthesized Ni(II)-terephthalate complex compared to that of obtained from the DMF solvents.

Eu2+-activated hexagonal aluminate solid solution phosphors with high quantum efficiency and anti-thermal quenching for pc-LEDs

The luminescence quantum efficiency and thermal stability are important parameters for phosphors when applied in phosphor-converted white light-emitting diodes (pc-LEDs). A facile solid solution strategy was applied to improve the quantum efficiency and thermal stability based on Na-β-Al2O3:Eu2+. Ba2+, Mg2+, and Ge4+ are introduced to replace Na+ and Al3+ simultaneously, besides the substitution of Na+ by Eu2+. X-ray powder diffraction, scanning electron microscopy combining elemental mapping indicate the formation of solid solution from Na-β-Al2O3:Eu2+ and BaMgAl10O17:Eu2+. The internal and external quantum efficiencies (IQE, EQE) both increase through solid solution with nearly unchanged blue emission at 468 nm. The IQE and EQE values of nominal Na1.6-xBaxAl11-3xMg2xGexO17+δ:0.2Eu2+ (x = 0.3) are as high as 90.4 % and 68.1 %, respectively. Furthermore, the thermoluminescent curves suggest that the defects decrease by introducing Ba2+, Mg2+, and Ge4+ ions. Therefore, the anti-thermal quenching degree decreases, resulting in better thermal stability. The proto-type white pc-LED based on the as-synthesized blue phosphor has a color-rendering index of 87, and nearly unchanged emission profile versus driving currents. The solid-solution phosphors show their potential as blue-emitting component for white pc-LEDs.

Visible Light Induced Photocatalytic Degradation of Diclofenac in Aqueous Solution Using Fabricated ZnO/g-C3N4 by Facile Calcination Technique.

The ability of the heterojunction between two distinct semiconductors with appropriately matched band gaps to improve the separation of photogenerated electron-hole pairs has been demonstrated to enhance photocatalytic activity. Hence, ZnO/g-C3N4 composites have been fabricated by the facile deposition and calcination of ZnO and g-C3N4. X-ray photoelectron spectroscopy, powder X-ray diffraction, and Fourier transform infrared spectroscopy confirm the formation of the composite. Scanning electron microscope, transmission electron microscope, and energy-dispersive X-ray spectroscopy morphological analysis reveal that ZnO was homogeneously spread over the g-C3N4 surface. UV-vis diffuse reflectance spectroscopy analysis shows the slightly enhanced visible light absorption ability of the composite. Photoluminescence (PL) spectroscopy and electrochemical impedance spectroscopy analysis prove the higher charge separation of the composite during the irradiation of light. The composite shows admirable photocatalytic efficiency in the visible light-driven photocatalytic degradation of an aqueous diclofenac (DFC) solution. The superoxide anion radical (•O2 -) and hydroxyl radical (•OH) act as reactive species during the degradation reaction. Probable reaction mechanisms have been proposed.

A novel red emitting Eu3+ doped CaSiO3 nanophosphor derived from agro-wastes for advanced forensic applications

The modified sol–gel approach was utilised to synthesise Eu3+ (1–5 mol%) doped CaSiO3 nanophosphors (NPs) using eggshell (ES) and rice husk ash (RHA) as precursors for SiO2 and CaO, respectively. Powder X-ray diffraction (PXRD) peaks confirm the monoclinic structure of the powdered samples. The photoluminescence (PL) emission spectra display distinct emission peaks corresponding to Eu3+ ions. After optimizing the Eu3+ ion concentration, the highest intensity (CaSiO3:3Eu3+) was achieved at 3 mol%. As the concentration increased beyond this point, the emission intensity decreased due to concentration quenching (CQ). Temperature-dependent photoluminescence (TDPL) was investigated in the range of 303 to 443 K. The results demonstrated that emissions at elevated temperatures are significantly stronger than those at ambient temperature. TDPL studies revealed excellent thermal stability, with emission intensity remaining at 87.5 % even at 423 K. Additionally, the phosphor’s absolute sensitivity of 0.003 K−1 and relative sensitivity of 1.44 % K−1 highlight its strong potential for temperature sensing applications. The suitability of the phosphor for the powder dusting method in fingerprint (FP) detection on various surfaces was also assessed. Under 365 nm UV light, the CaSiO3:3Eu3+ phosphor clearly reveals the level 1–3 structure of LFPs.

Synthesis and characterization of copper tartrate Crystals grown in silica gel

Copper tartrate crystals were grown by the ‘Single diffusion’ method in silica gel by gel growth technique. Optimum conditions of crystal growth such as pH, specific gravity, aging period of gel, concentration of reactants in gels were determined by varying them. The unit cell of a grown crystal is Orthorhombic as characterized using Powder X-Ray diffraction. The Fourier transform infrared spectrum in the range 400–4,000 cm-1 were recorded and the vibrational bands corresponding to functional groups is assigned. FTIR has confirmed the carboxyl as functional group and the other bonds between atoms. XPS has concluded paramagnetic nature and the presence of cu2+ ion.

Study of Structural, Thermal and Electrical Properties of Sr-Doped CaMnO<sub>3</sub>

Sr-doped CaMnO3 materials have wide applications due to their thermal and electrical properties. The importance of the synthesis of Sr-doped CaMnO3 material for various applications encourages researchers to evaluate and refine the synthesis process. In this study, Ca1-xSrxMnO3 (x = 0; 0.05; 0.1; 0.15; 0.2) system has been prepared by sol-gel method followed by conventional sintering process at 850°C for 8 hr. A thorough discussion has been made on the outcomes derived from the investigation on the structural, electrical, and thermal properties of Sr-doped CaMnO3 system using powder x-ray diffraction, scanning electron microscopy, energy dispersive spectroscopy, DC fourprobe method, thermal expansion studies, and thermoelectric power analyses. The XRD patterns of all prepared samples exhibited single phase with orthorhombic crystal structure (space group Pnma). Rietveld refinements were performed for all the patterns by using Fullprof software to extract the structural properties. The values of unit cell volume of samples tend to increase with the increment of dopant concentration, whereas the crystallite size values were decreased with dopant concentration. The microstructures of all the samples were studied using SEM, and elemental compositions were confirmed from the EDS results. Linear thermal expansion coefficients of all the samples were found to have moderate values in the temperature range from 30°C to 800°C. The electrical properties of all the system of samples were studied in the temperature range from 30°C to 400°C using DC fourprobe conductivity setup. It was found that all the samples exhibited semiconductor nature. Sr-content on the A-site suppress the electrical resistivity up to 10% of concentration and 5% dopant content exhibited the lowest electrical resistivity. The values of Seebeck coefficient found to vary from -160 µV/K to -124 µV/K with the increase of dopant content in the parent compound.

Highly Efficient Detection of Pd2+ in Aqueous Medium by an Elusive Mn(II) Coordination Polymer.

Herein, we report the synthesis of a Mn(II)-based coordination polymer (CP); and its structure, phase consistency and thermal stability have been established by single-crystal X-ray diffraction (SCXRD), powder X-ray diffraction (PXRD) and thermalgravimetric analysis (TGA) respectively. This is the first example of paramgnetic Mn(II)-based CP that acts as pH-dependent emitting material [λem=525 nm (pH=2.0-4.0) and 450 nm (pH=5.0-12.0)]. Its emission is quenched by Pd2+ in aqueous medium in presence of other thirteen cations with reasonably low pH-dependent limits of detection (LODs) [21.178 ppb (pH=3), 15.005 ppb (pH=7.0) and 59.940 ppb (pH=10.0)] as described by well-established mechanism. Therefore, urgency of such stable sensor remains high in regard to the environmental pollution.

Viologen-Directed Silver-Thiocyanate-Based Photocatalyst for Rhodamine B Degradation in Artificial Seawater.

Photocatalytic degradation is a leading technology for complete mineralization of organic dyes in the ocean. In this work, a new viologen-bearing silver-thiocyanate-based photocatalyst, i.e., {(i-PrV)[Ag2(SCN)4]}n (i-PrV2+ = isopropyl viologen) has been synthesized and structurally determined, with results showing that it can exhibit excellent degradation performance on rhodamine B (RhB) in artificial seawater. The planar i-PrV2+ dications are confined in the free voids of the [Ag2(SCN)4]n2n- layer with a two-dimensional (6,3) mesh, and strong C-H···S hydrogen bonds contribute to its structural stabilization. This photocatalyst was further characterized by powder X-ray diffraction (PXRD), UV-Vis, fluorescence, and photo/electrical responsive measurements, pointing to its application in visible-light-driven catalysis. Interestingly, using this photocatalyst, good photocatalytic degradation performance on rhodamine B in artificial seawater could be observed. The dye pollutant could be degraded with a high degradation ratio of 87.82% in 220 min. This work provides a promising catalyst for organic dye-type ocean pollutant treatments.

Microstructural and Oxidation Effects of Nb Additions to U3Si2

U3Si2 is a long term, accident-tolerant nuclear fuel candidate for light-water reactors because of its superior thermal conductivity and increased uranium density when compared to traditional uranium dioxide (UO2). While reducing internal thermal stresses and increasing efficiency, U3Si2 exhibits energetic oxidation during certain off-normal and accident scenarios, which include coolant or steam exposure. To mitigate this, Nb is investigated as an alloy constituent to enhance corrosion resistance and increase mechanical strength. The work presented investigates the response of Nb-alloyed U3Si2 to steam atmospheres. A thermogravimetric analysis is conducted in flowing steam to T > 1000 °C to assess oxidation resistance. The phase characterization of as-melted, thermally annealed and post-oxidation compositions with up to 12 vol% Nb by powder X-ray diffraction, scanning electron microscopy, and energy dispersive spectroscopy is reported.