Inorganic Chemistry最新文献

Inorganic materials doped with chromium (Cr) ions generate remarkable and adjustable broadband near-infrared (NIR) light, offering promising applications in the fields of imaging and night vision technology. However, achieving high efficiency and thermal stability in these broadband NIR phosphors poses a significant challenge for their practical application. Here, we employ crystal field engineering to modulate the NIR characteristics of Cr³⁺-doped Gd₃Ga₅O₁₂ (GGG). The Gd₃Mg_xGa_5-2xGe_xO₁₂ (GMGG):7.5% Cr³⁺ (x = 0, 0.05, 0.15, 0.20, and 0.40) phosphors with NIR emission are developed through the cosubstitution of Mg²⁺ and Ge⁴⁺ for Ga³⁺ sites. This cosubstitution strategy also effectively reduces the crystal field strength around Cr³⁺ ions, which results in a significant enhancement of the photoluminescence (PL) full width at half-maximum (fwhm) from 97 to 165 nm, alongside a red shift in the PL peak and an enhancement of the PL intensity up to 2.3 times. Notably, the thermal stability of the PL behaviors is also improved. The developed phosphors demonstrate significant potential in biological tissue penetration and night vision, as well as an exceptional scintillation performance for NIR scintillator imaging. This research paves a new perspective on the development of high-performance NIR technology in light-emitting diodes (LEDs) and X-ray imaging applications.

The single-step purification of ethylene (C₂H₄) from a mixture of carbon dioxide (CO₂), acetylene (C₂H₂), ethylene (C₂H₄), and ethane (C₂H₆) was achieved through MOF Compound-1, where the aromatic pore surface and carboxylates selectively recognized C₂H₆ and CO₂, respectively, resulting in a reversal of the adsorption orders for both gases (C₂H₆ > C₂H₄ and CO₂ > C₂H₄). Breakthrough testing verified that the C₂H₄ purification ability could be enhanced 2.6 times after adding impure CO₂. Grand Canonical Monte Carlo (GCMC) simulations demonstrate that there are interactions between CO₂ and C₂H₆ molecules as well as between CO₂ molecules themselves. These interactions contribute to the enhancement of the C₂H₄ purification ability upon the addition of CO₂ and the increased adsorption of CO₂.

Chalcogenide perovskites (CPs) have recently attracted interest as a class of materials with practical potential in optoelectronics and have been suggested as a more thermally stable alternative to intensely studied halide perovskites (HPs). Here we report a comparative study of the thermal stability of representative HPs, MAPbI₃ (MA = CH₃NH₃⁺, methylammonium) and CsPbI₃, and a series of CPs with compositions BaZrS₃, β-SrZrS₃, BaHfS₃, SrHfS₃. Changes in the crystal structure, chemical composition, and optical properties upon heating in air up to 800 °C were studied using thermogravimetric analysis, temperature-dependent X-ray diffraction, energy-dispersive X-ray spectroscopy, and diffuse reflectance spectroscopy. While HPs undergo phase transitions and thermally decompose at temperatures below 300 °C, the CPs show no changes in crystal phase or composition when heated up to at least 450 °C. At 500 °C CPs oxidize on time scales of several hours, forming oxides and sulfates. The structural origins of the higher thermal and phase stability of the CPs are discussed.

The chemical fixation of CO₂ into epoxides for the synthesis of cyclic carbonates is an appealing solution to both reduce global CO₂ emission and produce fine chemicals, but it is still a prime challenge to develop a low-cost, earth-abundant, yet efficient solid catalyst. Herein, Fe₂O₃/NiFe₂O₄ heterostructures are facilely constructed for the highly efficient cycloaddition of CO₂ with styrene oxide (SO) to produce styrene carbonate (SC). Both experimental findings and density functional theory (DFT) calculations substantiate the prominent electron transfer and charge redistribution within the heterointerfaces between the biphasic components, which induce a unique interfacial microenvironment that can facilitate the adsorption and activation of SO. This endows the biphasic catalyst with a substantially higher reactivity than the individual components. This study sheds new insights into the establishment of heterostructured catalysts consisting of transitional metal oxides for the high-efficiency production of SC from the cycloaddition of CO₂ with SO.

Cobalt (Co)-based materials have been widely investigated as hopeful noble-metal-free alternatives for the oxygen evolution reaction (OER) in alkaline electrolytes, which is crucial for generating hydrogen by water electrolysis. Herein, cobalt-based telluride particles with good electronic conductivity as anodic electrocatalysts were prepared under vacuum by the solid-state strategy, which display remarkable activities toward the OER. Nickel (Ni) and iron (Fe) codoped cobalt telluride (NiFe-CoTe) exhibits an overpotential of 321 mV to achieve a current density of 10 mA cm^-2 and a Tafel slope of 51.8 mV dec^-1, outperforming the performances of CoTe, CoTe₂, and IrO₂. According to the DFT calculation, the adsorbed hydroxyl-assisted adsorbate evolution mechanism was proposed for the OER process of NiFe-CoTe, which reveals the synergetic effect toward OER induced by codoping of the Ni and Fe atoms. This work proposes a rational strategy to prepare cobalt-based tellurides as efficient OER catalysts in alkaline electrolytes, providing a new strategy to prepare and regulate metal-based tellurides for catalysis and beyond.

The functionalization of polyoxovanadate clusters is promising but of great challenge due to the versatile coordination geometry and oxidation state of vanadium. Here, two unprecedented silsesquioxane ligand-protected "fully reduced" polyoxovanadate clusters were fabricated via a facial solvothermal methodology. The initial mixture of the two polyoxovanadate clusters with different colors and morphologies (green plate V₁₄ and blue block V₆) was successfully separated as pure phases by meticulously controlling the assembly conditions. Therein, the V₁₄ cluster is the highest-nuclearity V-silsesquioxane cluster to date. Moreover, the transformation from a dimeric silsesquioxane ligand-protected V₁₄ cluster to a cyclic hexameric silsesquioxane ligand-protected V₆ cluster was also achieved, and the possible mechanism termed "ligand-condensation-involved dissociation reassembly" was proposed to explain this intricate conversion process. In addition, the robust V₆ cluster was served as a heterogeneous catalyst for the synthesis of important heterocyclic compounds, quinazolinones, starting from 2-aminobenzamide and aldehydes. The V₆ cluster exhibits high activity and selectivity to access pure quinazolinones under mild conditions, where the high selectivity was attributed to the confinement effect of the macrocyclic silsesquioxane ligand constraining the molecular freedom of the reaction species. The stability and recyclability as well as the tolerance of a wide scope of aldehyde substrates endow the V₆ cluster with a superior performance and appreciable potential in catalytic applications.

Chromium-based metal-organic frameworks (Cr-MOFs) are very attractive in a wide range of applications due to their robustness and high porosity. However, the kinetic inertness of chromium ions results in the synthesis of Cr-MOFs often taking prolonged reaction times, which limit their industrial applications. Herein, we report a novel synthesis strategy based on coordination substitution, which overcomes the kinetic inertness of chromium ions and can synthesize Cr-MOFs in a shorter time. The versatility of this strategy has been demonstrated by producing several known Cr-MOFs, such as TYUT-96Cr, MIL-100Cr, MIL-101Cr, and MIL-53Cr. PXRD, SEM, TEM, 77 K N₂ adsorption, and TGA have proved that the Cr-MOFs synthesized using this new strategy have good crystallinity, high porosity, and excellent thermal stability. The synthesis mechanism was investigated using theoretical calculations.

Constructing the plasmonic metal/semiconductor heterostructure with a suitable Schottky barrier height (SBH) and the sufficiently reliable active sites is of importance to achieve highly efficient and selective photocatalytic CO₂ reduction into hydrocarbon fuels. Herein, we report Au/sulfur vacancy-rich ZnIn₂S₄ (Au/V_SR-ZIS) hierarchical photocatalysts, fabricated via in situ photodepositing Au nanoparticles (NPs) onto the nanosheet self-assembled ZnIn₂S₄ (ZIS) micrometer flowers (MFs) with rich sulfur vacancies (V_S). Density functional theory (DFT) calculations confirm that for the Au/V_SR-ZIS system, the Au NPs serve as the reaction sites for H₂O oxidation, and the V_SR-ZIS MFs serve as those for CO₂ reduction. The rich V_S in the Au/V_SR-ZIS hybrid can reduce its SBH so as to boost more hot electrons in the Au NPs across its Schottky barrier and then inject into the conduction band (CB) of the V_SR-ZIS MFs. In addition, V_S can also act as the electron sink to trap the photogenerated electrons, retarding the recombination of photogenerated carriers. The two merits effectively enhance the photogenerated electron density in the surface of V_SR-ZIS MFs, availing CO₂ photoreduction. In addition, the introduction of rich V_S in the Au/V_SR-ZIS hybrid can offer more active sites, benefiting the CO₂ adsorption and accelerating the desorption of CO* from the surface of the photocatalyst. Therefore, under visible light illumination with no sacrificial reagent, the optimum photocatalyst (Au/V_SR-ZIS-0.4) presents the enhanced and selective CO₂ photoreduction into CO (8.15 μmol g^-1h^-1 and near 100%), which are superior to those of most of ZIS-based and plasmon-based photocatalysts. The photocatalytic activity is about 40.0-fold as high as that of the Vs-poor-ZIS (V_SP-ZIS) MFs. This work contributes a viable strategy for designing highly efficient plasmonic photocatalysts by using the synergism of the anion vacancies and the optimized SBH induced by them.