Stabilization of the cubic, fast-ion conducting phase of Li7La3Sn2O12 garnet by gallium doping.

All-solid-state batteries present promising high-energy-density alternatives to conventional Li-ion chemistries, and Li-stuffed garnets based on Li7La3Zr2O12 (LLZO) remain a forerunner for candidate solid-electrolytes. One route to access fast-ion conduction in LLZO phases is to stabilize the cubic LLZO phase by doping on the Li sites with aliovalent ions such as Al3+ or Ga3+. Despite prior attempts, the stabilization of the cubic phase of isostructural Li7La3Sn2O12 (LLSO) by doping on the Li sites has up to now not been realised. Here, we report a novel cubic fast-ion conducting Li7La3Sn2O12-type phase stabilized by doping Ga3+ in place of Li. 0.3 mole of gallium per formula unit of LLSO were needed to fully stabilize the cubic garnet, allowing structural and electrochemical characterizations of the new material. A modified sol-gel synthesis approach is introduced in this study to realise Ga-doping in LLSO, which offers a viable route to preparing new Sn-based candidate solid-electrolytes for all-solid-state battery applications.

Fe/Co-MOF Nanocatalysts: Greener Chemistry Approach for the Removal of Toxic Metals and Catalytic Applications.

This study describes the preparation of new bimetallic (Fe/Co)-organic framework (Bi-MOF) nanocatalysts with different percentages of iron/cobalt for their use and reuse in adsorption, antibacterial, antioxidant, and catalytic applications following the principles of green chemistry. The prepared catalysts were characterized using several techniques, including X-ray powder diffraction, Fourier transform infrared spectroscopy, transmission electron microscopy, and scanning electron microscopy. These techniques proved the formation of MOFs, and the average crystallite sizes were 25.3-53.1, 27.6-67.2, 3.0-18.9, 3.0-12.9, and 3.0-23.6 nm for the Fe-MOF, Co-MOF, 10%Fe:90%Co-MOF, 50%Fe:50%Co-MOF, and 90%Fe:10%Co-MOF samples, respectively. The nanoscale (Fe/Co) Bi-MOF catalysts as efficient heterogeneous solid catalysts showed high catalytic activity with excellent yields and short reaction times in the catalytic reactions of quinoxaline and dibenzoxanthene compounds, in addition to their antioxidant and antibacterial activities. Furthermore, the nanoscale (Fe/Co) Bi-MOF catalysts efficiently removed toxic metal pollutants (Pb2+, Hg2+, Cd2+, and Cu2+) from aqueous solutions with high adsorption capacity.

Synthesis, photocatalytic and antidiabetic properties of ZnO/PVA nanoparticles.

A series of ZnO and ZnO/poly(vinyl alcohol) (PVA) catalysts were prepared using sol-gel method. An X-ray diffraction analysis confirmed the existence of the wurtzite ZnO phase, and scanning electron microscopy (SEM) observation revealed the formation of spherical ZnO and ZnO/PVA nanoparticles. The decomposition of methylene blue (MB) and methyl orange (MO) induced by the synthesized pure ZnO and ZnO/PVA nanoparticles was studied under ultraviolet-visible irradiation. Among the catalysts evaluated, ZnO/5PVA was the most active in the decomposition of MB, whereas ZnO/7PVA was the most active catalyst in the decomposition of MO. Moreover, an investigation of the biological activity of pure ZnO and ZnO/PVA indicated that ZnO/5PVA exhibited the best performance in lowering the glucose level in diabetic rats.

Synthesis of sulfamic acid supported on Cr-MIL-101 as a heterogeneous acid catalyst and efficient adsorbent for methyl orange dye.

Typical highly porous metal-organic framework (MOFs) materials based on chromium benzenedicarboxylates (Cr-BDC) were prepared through a one-pot hydrothermal synthesis, and were then modified by loading the appropriate ratio of sulfamic acid (SA) using a simple impregnation technique. Pure and modified MIL-101 was characterized by XRD, TEM, SEM and FT-IR measurements. TEM and SEM measurements confirmed that the MIL-101 particles preserved their regular octahedral structure after loading with different weight contents of sulfamic acid. The total number of acid sites and Brønsted to Lewis acid sites ratio (B/L) were examined using potentiometric titration and pyridine adsorption. The acid strength and surface acidity of SA/MIL-101 gradually increased after the modification of Cr-MIL-101 by sulfamic acid crystals up to 55 wt%, then decreased again. The catalytic performance of the solid catalysts was confirmed in the synthesis of 14-phenyl-14H-dibenzo [a,j] xanthene and 7-hydroxy-4-methyl coumarin. In the two reactions, the sample with 55% sulfamic acid loaded on MIL-101 displayed the highest catalytic activity and acidity. The adsorption behaviors of sulfamic acid loaded on MIL-101 materials for methyl orange (MO) as an anionic dye were studied, and were exceptionally suitable for the Langmuir adsorption isotherm. All loaded adsorbents showed high adsorption capacity for methyl orange at 25 °C. The results indicate that the adsorption capacity was modified by changing the amount of sulfamic acid loaded on MIL-101.