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1. Mo ₃ S ₁₃ Chalcogel: A High‐Capacity Electrode for Conversion‐Based Li‐Ion Batteries

   https://doi.org/10.1002/cssc.202400084  

   Islam, Taohedul; Chandra Roy, Subrata; Bayat, Sahar; Adigo Weret, Misganaw; Hoffman, Justin M.; Rao, Keerthan R.; Sawicki, Conrad; Nie, Jing; Alam, Robiul; Oketola, Oluwaseun; et al (April 2024, ChemSusChem)

   Abstract Despite large theoretical energy densities, metal‐sulfide electrodes for energy storage systems face several limitations that impact the practical realization. Here, we present the solution‐processable, room temperature (RT) synthesis, local structures, and application of a sulfur‐rich Mo₃S₁₃chalcogel as a conversion‐based electrode for lithium‐sulfide batteries (LiSBs). The structure of the amorphous Mo₃S₁₃chalcogel is derived throughoperandoRaman spectroscopy, synchrotron X‐ray pair distribution function (PDF), X‐ray absorption near edge structure (XANES), and extended X‐ray absorption fine structure (EXAFS) analysis, along with ab initio molecular dynamics (AIMD) simulations. A key feature of the three‐dimensional (3D) network is the connection of Mo₃S₁₃units through S−S bonds. Li/Mo₃S₁₃half‐cells deliver initial capacity of 1013 mAh g⁻¹during the first discharge. After the activation cycles, the capacity stabilizes and maintains 312 mAh g⁻¹at a C/3 rate after 140 cycles, demonstrating sustained performance over subsequent cycling. Such high‐capacity and stability are attributed to the high density of (poly)sulfide bonds and the stable Mo−S coordination in Mo₃S₁₃chalcogel. These findings showcase the potential of Mo₃S₁₃chalcogels as metal‐sulfide electrode materials for LiSBs. 

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2. Local lattice distortions and dynamics in extremely overdoped superconducting YSr ₂ Cu _2.75 Mo _0.25 O _7.54

   https://doi.org/10.1073/pnas.1918704117  

   Conradson, Steven D.; Geballe, Theodore H.; Gauzzi, Andrea; Karppinen, Maarit; Jin, Changqing; Baldinozzi, Gianguido; Li, Wenmin; Cao, Lipeng; Gilioli, Edmondo; Jiang, Jack M.; et al (March 2020, Proceedings of the National Academy of Sciences)

   A common characteristic of many “overdoped” cuprates prepared with high-pressure oxygen is T c values ≥ 50 K that often exceed that of optimally doped parent compounds, despite O stoichiometries that place the materials at the edge or outside of the conventional boundary between superconducting and normal Fermi liquid states. X-ray absorption fine-structure (XAFS) measurements at 52 K on samples of high-pressure oxygen (HPO) YSr 2 Cu 2.75 Mo 0.25 O 7.54 , T c = 84 K show that the Mo is in the (VI) valence in an unusually undistorted octahedral geometry with predominantly Mo neighbors that is consistent with its assigned substitution for Cu in the chain sites of the structure. Perturbations of the Cu environments are minimal, although the Cu X-ray absorption near-edge structure (XANES) differs from that in other cuprates. The primary deviation from the crystal structure is therefore nanophase separation into Mo- and Cu-enriched domains. There are, however, indications that the dynamical attributes of the structure are altered relative to YBa 2 Cu 3 O 7 , including a shift of the Cu-apical O two-site distribution from the chain to the plane Cu sites. Another effect that would influence T c is the possibility of multiple bands at the Fermi surface caused by the presence of the second phase and the lowering of the Fermi level. 

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3. Ion-induced surface reactions and deposition from Pt(CO) ₂ Cl ₂ and Pt(CO) ₂ Br ₂

   https://doi.org/10.3762/bjnano.15.115  

   Abdel-Rahman, Mohammed K; Eckhert, Patrick M; Chaudhary, Atul; Johnson, Johnathon M; Yu, Jo-Chi; McElwee-White, Lisa; Fairbrother, D Howard (January 2024, Beilstein Journal of Nanotechnology)

   Ion beam-induced deposition (IBID) using Pt(CO)₂Cl₂and Pt(CO)₂Br₂as precursors has been studied with ultrahigh-vacuum (UHV) surface science techniques to provide insights into the elementary reaction steps involved in deposition, complemented by analysis of deposits formed under steady-state conditions. X-ray photoelectron spectroscopy (XPS) and mass spectrometry data from monolayer thick films of Pt(CO)₂Cl₂and Pt(CO)₂Br₂exposed to 3 keV Ar⁺, He⁺, and H₂⁺ions indicate that deposition is initiated by the desorption of both CO ligands, a process ascribed to momentum transfer from the incident ion to adsorbed precursor molecules. This precursor decomposition step is accompanied by a decrease in the oxidation state of the Pt(II) atoms and, in IBID, represents the elementary reaction step that converts the molecular precursor into an involatile PtX₂species. Upon further ion irradiation these PtCl₂or PtBr₂species experience ion-induced sputtering. The difference between halogen and Pt sputter rates leads to a critical ion dose at which only Pt remains in the film. A comparison of the different ion/precursor combinations studied revealed that this sequence of elementary reaction steps is invariant, although the rates of CO desorption and subsequent physical sputtering were greatest for the heaviest (Ar⁺) ions. The ability of IBID to produce pure Pt films was confirmed by AES and XPS analysis of thin film deposits created by Ar⁺/Pt(CO)₂Cl₂, demonstrating the ability of data acquired from fundamental UHV surface science studies to provide insights that can be used to better understand the interactions between ions and precursors during IBID from inorganic precursors. 

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4. K–Co–Mo–S _x chalcogel: high-capacity removal of Pb ²⁺ and Ag ⁺ and the underlying mechanisms

   https://doi.org/10.1039/D4TA05158K  

   Nie, Jing; Chandra_Roy, Subrata; Dhami, Sital; Islam, Taohedul; Amin, Ruhul; Zhu, Xianchun; Taylor-Pashow, Kathryn; Han, Fengxiang X; Islam, Saiful M (November 2024, Journal of Materials Chemistry A)

   Disordered aggregated porous nanoparticles of KCMS are highly efficient and have exceptionally high sorption capacity in removing Ag⁺and Pb²⁺following the exchange of K⁺and Co²⁺ions bonded electrostatically and covalently in KCMS, respectively. 

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5. High pressure raman spectroscopy and X-ray diffraction of K2Ca(CO3)2 bütschliite: multiple pressure-induced phase transitions in a double carbonate

   https://doi.org/10.1007/s00269-023-01262-5  

   Zeff, G; Kalkan, B; Armstrong, K; Kunz, M; Williams, Q (March 2024, Physics and Chemistry of Minerals)

   Abstract The crystal structure and bonding environment of K₂Ca(CO₃)₂bütschliite were probed under isothermal compression via Raman spectroscopy to 95 GPa and single crystal and powder X-ray diffraction to 12 and 68 GPa, respectively. A second order Birch-Murnaghan equation of state fit to the X-ray data yields a bulk modulus,$${K}_{0}=46.9$$ $K_0=46.9$GPa with an imposed value of$${K}_{0}^{\prime}= 4$$ $K_0^{\prime }=4$for the ambient pressure phase. Compression of bütschliite is highly anisotropic, with contraction along thec-axis accounting for most of the volume change. Bütschliite undergoes a phase transition to a monoclinicC2/mstructure at around 6 GPa, mirroring polymorphism within isostructural borates. A fit to the compression data of the monoclinic phase yields$${V}_{0}=322.2$$ $V_0=322.2$ Å³$$,$$ $,$$${K}_{0}=24.8$$ $K_0=24.8$GPa and$${K}_{0}^{\prime}=4.0$$ $K_0^{\prime }=4.0$using a third order fit; the ability to access different compression mechanisms gives rise to a more compressible material than the low-pressure phase. In particular, compression of theC2/mphase involves interlayer displacement and twisting of the [CO₃] units, and an increase in coordination number of the K⁺ion. Three more phase transitions, at ~ 28, 34, and 37 GPa occur based on the Raman spectra and powder diffraction data: these give rise to new [CO₃] bonding environments within the structure. 

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