SnS
has been extensive studied as an anode material for sodium storage owing to its high theoretical specific capacity, whereas the unsatisfied initial Coulombic efficiency (ICE) caused by the ...partial irreversible conversion reaction during the charge/discharge process is one of the critical issues that hamper its practical applications. Hence, heterostructured SnS
/Mn
SnS
/carbon nanoboxes (SMS/C NBs) have been developed by a facial wet-chemical method and utilized as the anode material of sodium ion batteries. SMS/C NBs can deliver an initial capacity of 841.2 mAh g
with high ICE of 90.8%, excellent rate capability (752.3, 604.7, 570.1, 546.9, 519.7, and 488.7 mAh g
at the current rate of 0.1, 0.5, 1.0, 2.0, 5.0, and 10.0 A g
, respectively), and long cycling stability (522.5 mAh g
at 5.0 A g
after 500 cycles). The existence of SnS
/Mn
SnS
heterojunctions can effectively stabilize the reaction products Sn and Na
S, greatly prevent the coarsening of nanosized Sn
, and enhance reversible conversion--alloying reaction, which play a key role in improving the ICE and extending the cycling performance. Moreover, the heterostructured SMS coupled with the interacting carbon network provides efficient channels for electrons and Na
diffusion, resulting in an excellent rate performance.
In this investigation, we focused on the synthesis and characterization of CsCaF3 compound doped with europium (Eu3+) ions using a solid-state route. To analyze the crystal structure of the ...synthesized phosphors, X-ray diffraction analysis was employed. Additionally, the doped sample underwent examination of surface morphology and elemental composition through Field Emission Scanning Electron Microscopy and EDAX mapping. The color of the pure and doped CsCaF3 sample was quantified and fitted using Color coordinate graph by the Commission Internationale de l'Eclairage (CIE). The red emission on the doped CsCaF3 compound was detected at 465 nm, which is the transition from 5D0 to 7Fj (j = 0, 1, 2, and 3). The 0.5 mol. % Eu3+ doped CsCaF3 sample was found to have a color purity of 81% and an associated color temperature of 1660 K, indicating its suitability for aesthetic lighting applications. Furthermore, thermoluminescence study, electron paramagnetic resonance (EPR), and effective atomic number (Zeff) calculations were conducted to provide valuable information for potential radiation dosimetry applications.
This work studies the optoelectronic, and structural characteristics of CsPbIBr2 perovskite solar cells (PSCs) improved by 4 % Zirconium (Zr) doping and a bilayer electron transport layers (ETLs) ...composed of TiO2 and Zr-doped WO3. X-ray diffraction (XRD) examination of pure and Zr-doped CsPbIBr2 films revealed increased crystal size (39.2–41.2 nm) and lowered lattice constant following Zr doping, suggesting better crystallinity. The calculated energy band gap of pristine and Zr-doped CsPbIBr2 film decreases (1.986–1.926 eV), which improves the light absorption efficiency, while the increase in the refractive index implies that light is slowed down more as it passes through the material, which increases light trapping and absorption within the material. The XRD of Zr-WO3 ETL indicated a monoclinic crystal structure and increased lattice constant, allowing charge carrier transmission. Raman spectroscopy confirms the structural integrity of Zr-WO3. UV–Vis absorption spectra suggest enhanced absorption in the visible region and higher bandgap compared to Zr-doped CsPbIBr2. J-V tests reveal an efficiency rise from 8.54 % to 10.20 % with the proposed of double ETLs, exhibiting substantial breakthroughs in PSCs performance.
Enhanced Efficiency through Zr doping and bilayer ETL of Zr–CsPbIBr2: Increased Grain Size, Reduced Energy Band Gap, Elevating Efficiency from 8.54 % to 10.20 %. Display omitted
•The inclusion of 4 % Zr doping into CsPbIBr2 perovskite films, significantly improves the structural and optoelectronic properties of solar cells.•The dual-layer ETLs comprising TiO2) and 4 % Zr-WO3, enhancing the optoelectronic and photovoltaic performance.•The efficiency increases in PSCs from 8.54 % to 10.20 %, evidenced through J-V testing with the introduction of the double ETLs.
We report detailed investigations on the synthesis, structural, morphology, electronic/atomic structure and photocatalyst properties of Cu doped TiO2, ZnO and Ni(OH)2 nanostructures. All of the ...samples were synthesized by using the chemical precipitation method. Samples were characterized by X-ray diffraction (XRD), transmission electron microscope (TEM), X-ray absorption near edge structure (XANES), extended X-ray absorption fine structure (EXAFS) and photocatalyst measurements. XRD studies revealed single phase nature of the samples and omitted the presence of trivial metallic or binary oxide phases. TiO2 set of samples have shown nanorod kind of morphology, however TEM images of ZnO and Ni(OH)2 set of samples depicted the spherical morphology of particles. XANES spectra at the Cu K-edge and Cu L-edge, along with the atomic multiplet calculations, revealed the predominance of Cu2+ ions in all of the samples, within the entire doping range. Ti L-edge and Ti K-edge XANES confirmed the existence of Ti4+ ions in the pure and Cu doped TiO2 samples with anatase local structure. Zn L-edge XANES results confirmed the divalent character of Zn ions in the pure and Cu doped ZnO, which is further validated by the Zn K-edge XANES. Ni L-edge and Ni K-edge XANES conveyed the +2 valence state of Ni ions in the pure and Cu doped Ni (OH)2 samples. EXAFS analysis at the Cu K-edge nullifies the formation of Cu metallic clusters and other trivial phases, suggesting random distribution of Cu atoms in the oxide materials. Though, local atomic arrangement of Cu ions is disparate in the different oxide compounds. As an application of the pure and Cu doped TiO2, ZnO and Ni(OH)2 nanostructures, towards the degradation of water pollutant dyes, we demonstrate that all of the samples can serve as effective photocatalyst materials towards the degradation of methyl orange aqueous pollutant dye under the UV-light irradiation.
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•Pure and Cu doped TiO2, ZnO and Ni(OH)2 photocatalyst were synthesized using co-precipitation method.•XRD, HR-TEM, XANES, EXAFS and photocatalysis measurements were performed.•Presence of Cu2+, Ti4+, Zn2+, Ni2+ ions was confirmed by XANES.•Atomistic local information on the bond length and coordination number was studied by experimental EXAFS and theoretical simulation.•Orbital hybridization of Cu and host metal (Ti, Zn and Ni) leads to superior photocatalyst performance.
Tin anodes show a rich structure and reaction chemistry which we have investigated in detail. Upon discharge five plateaus are observed corresponding to β-Sn, an unidentified phase (Na/Sn = 0.6), an ...amorphous phase (Na/Sn = 1.2), a hexagonal R-3m Na5Sn2, and fully sodiated I-43d Na15Sn4. With charging there are six plateaus related to the formation of Na5Sn2 followed by the formation of amorphous phases and β-Sn. Upon cycling the formation of metastable Na5Sn2 seems to be suppressed.
Theoretical voltages calculated from existing crystal structures using DFT provide a good match with constant current and quasi-equilibrium measurements (GITT). Search for additional (meta)stable phases using cluster-expansion method predicts many phases lower in energy than the convex hull obtained from known structures, including the R-3m Na5Sn2 phase. The presence of multiple phases in varying lattices with similar formation energy suggests why the reaction mechanism is non-reversible. 119Sn Mössbauer spectroscopy results indicate a decrease of the isomer shift with increasing Na/Sn content, which is less pronounced than for Li–Sn compounds likely due to the lower electropositivity of Na.
The electrode surface is terminated with an SEI layer rich in carbonates (Na2CO3 and Na CO3R) as evidenced by XPS. After charge at 2 V, strong evidence for the formation of oxidized Sn4+ is obtained. Subjecting the electrode to a rest after charge at 2 V reveals that aging in the electrolyte reduces the oxidized Sn4+ into Sn2+ and Sn0, and concomitantly suppresses the electrolyte decomposition represented by an anomalous discharge plateau at 1.2 V. Thereby, the catalytic decomposition of the electrolyte during discharge is caused by nanosized Sn particles covered by oxidized Sn4+ and not by pure metallic Sn.
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► Bulk structure of Na–Sn studied by XRD, DFT and Mössbauer spectroscopy. ► Identification of new R-3m phase of composition Na5Sn2. ► Surface chemistry probed by XPS as a function of Na content. ► Catalytic decomposition of electrolyte caused by Sn4+ and not metallic Sn.
•The structural characterization of EMBIT was performed combining experimental and theoretical methods.•The molecular electrostatic potential and the energy gap between LUMO and HOMO molecular ...orbitals have been computed.•Hirshfeld surface analysis and fingerprint plots furnished a detailed information on the molecular packing and the contributions of the various interactions to the crystal lattice.•The non-linear optical (NLO) properties have been assessed by studying first and second order hyperpolarizabilities.•Molecular docking studies of EMBIT indicating favorable performance protein kinases ROCK 1 and 2 key factors in the Glaucoma disease.
(E)-3-(3-(2-methoxyphenyl)-4-methylthiazol-2(3H)-ylidene) benzo4,5 imidazo 1,2-c thiazole-1(3H)-thione (EMBIT) was synthesized and studied thoroughly by means of X-ray diffraction and molecular modeling. In this study, geometrical analysis together with FT-IR, NMR, and UV-Vis characterizations were performed. Using density functional theory and the B3LYP/6–311G++(d,p) set, geometric parameters accurately represent the structure, showing agreement between experimental and theoretical results. Various solvents were included in the calculations of the UV–Vis spectra, frontier molecular orbitals (FMOs), and global chemical reactivity descriptors (GCRD) calculations, revealing their potential for better prediction of energy gap values. The energy gap and some chemical descriptors analysis of the title compound indicated that it would be suitable for nonlinear optical properties and biological activity. Non-covalent bond interaction studies were conducted on EMBIT to investigate the intermolecular interactions. A deeper understanding of the electronic structure and chemical bonding patterns of the structure was gained by LOL and ELF studies.
The computed polarizabilities and hyperpolarizabilities indicated that the molecule has non-linear optical properties and assessed the influence of the energetic gap values and electron delocalization character on enhancing NLO proprieties. The predictions of EMBIT's biological activity suggested potential as a cure for glaucoma, and molecular docking revealed the various bonds involved against two potential critical glaucoma factors Rock1 and Rock2. Rock2 is found to have a superior binding affinity, as evidenced by its highest binding energy of -8.7 kcal/mol and a lower Ki inhibition constant of 0.97. The EMBIT ligand's effectiveness in inhibiting the Rock2 protein is highly likely, as suggested by this.
The impact of novel supplementary cementitious materials (SCMs) on the phase assemblage and the pore structure in cement pastes was studied and linked to their impact on the compressive strength in ...mortar. The composite cements analysed had a composition of 78 wt.% Portland cement, 18 wt.% SCM and 4 wt.% limestone filler, and the samples were cured sealed for 91 days at 20°C. The investigated SCMs comprise natural materials such as clays and volcanic rocks (rhyolite and hyaloclastite), and industrial products such as fly ash, slag, oil shale ash, bio-fuel ash or bio-coal fly ash. The results revealed that all the SCMs except oil shale ash contribute to the phase assemblage in a similar way, when clinker is replaced with 18 wt.% SCM. The pore structure of the different cement pastes was similar. Even when the composite cement pastes showed a higher total intruded pore volume compared to the Portland cement paste sample, these samples showed higher compressive strength. This indicates that total intruded porosity is not the only contribution to strength.
In-situ X-ray diffraction (XRD) is a powerful tool to assess the hydration of cementitious materials, providing time-resolved quantitative analysis with reasonable accuracy without disturbing sample. ...However, the lack of guidelines and well-established procedures for data collection and analysis is the limiting factor for spreading this technique. This paper discussed using in-situ laboratory XRD to assess cement hydration. The first part was dedicated to a literature review on the topic. Then, experimental strategies were discussed, and recommendations related to the data analysis routine were drawn; the advantages and limitations of this technique were also discussed. We can conclude that the critical factors for a successful analysis are the choice of an adequate experimental setup with good statistics and low measurement time, the proper consideration of different amorphous contributions in the XRD pattern, and a good data analysis routine. Independent techniques are highly recommended to support the in-situ XRD data.
•Polybromination by NBS and IR activation of potential antileishmanial guanidine.•Conformational study is performed by Nuclear Magnetic Resonance and SCXRD.•Hirshfeld surface and fingerprint plots of ...compounds showed a high Br—C contact.•XRPD and SCXRD X-ray patterns agree.•Conformational changes from Z to E promoted by polybromination.
Leishmaniasis is a neglected disease that affects regions such as South Asia, South Africa, and Latin America, less developed regions. The research proposed the conformational study of brominated guanidine compounds with potential antileishmanial activity using Nuclear Magnetic Resonance (NMR) and X-ray diffraction (XRD) techniques. The present study involves the brominated molecules LQOF-G2, LQOF-G30, LQOF-G35 and LQOF-G35-Br. The latter was synthesized by the reaction of LQOF-G35 with NBS under IR irradiation at 120 Watts of potency and dichloromethane as solvent by 12 h of exposition. The obtained results demonstrated the efficiency of the bromination method, since two bromine atoms entered the molecule. Furthermore, NMR analysis showed a conformational change from Z to E when compound LQOF-G35 was brominated to LQOF-G35-Br. This behavior was confirmed by a comparative XRD study of the LQOF-G35 and LQOF-G35-Br compounds. The antileishmanial activity of LQOF-G2 e LQOF-G35 motivated the synthesis of new brominated compounds LQOF-G30 e LQOF-G35-Br.
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