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Mixed platinum-ruthenium nanoparticles are prepared by water-in-oil reverse microemulsions of water/Triton X-100/propanol-2/cyclohexane. Nanoparticles formed in the microemulsions are characterized by transmission electron microscopy (TEM), electron diffraction (ED), X-ray diffractometry (XRD), energy-dispersive X-ray analysis (EDX), and X-ray photoelectron spectroscopy (XPS). TEM results show a narrow distribution of Pt-Ru nanoparticles. A homogeneous alloy structure in the bimetallic nanoparticles is indicated by XRD analysis and ED analysis. The composition of the Pt-Ru nanoparticles can be easily controlled by the relative concentration of Pt and Ru in the initial precursor solution. The composition that was in the Pt-Ru nano-alloy is found to be the same as that in the original precursor solution. XPS analysis reveals the presence of Pt and Ru metal as well as some oxide of ruthenium. The effect of precursor concentration on microemulsion drop size was investigated by photo correlation spectroscopy (PCS) measurement. The size of Pt-Ru nanoparticles depends on the concentration of precursor in the aqueous phase. At low precursor concentration, the final particle size is about 2.5 nm and appears to be limited by nucleation. At high precursor concentration, the final particle size is about 4.5 nm and appears to be limited by the collisions and mixing with thousands of hydrazine droplets. The Pt-Ru nanoparticles supported on a carbon electrode possessed high dispersion and high catalytic activity for methanol oxidation at room temperature.

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Pegmatites commonly form in the waning stage of magma evolution by fractional crystallization of volatile-rich magmas and may be important host rocks of strategic metals (e.g., Li, Be, Cs, Ta, and Nb) and high-quality gem minerals. This study reports new zircon U-Pb dating results and Hf isotopic compositions of the KLA803 pegmatite, the AZB-01 pegmatite, the JMK-09 pegmatite (abbreviated as the K-A-J pegmatites) and the Halong granite from the Chinese Altay to determine the potential petrogenetic relationships between them. The geochronological data document that the K-A-J pegmatites were emplaced at 224.6 ± 2.3 Ma, 191.6 ± 2.0 Ma and 192.0 ± 2.3 Ma, respectively, and they are characterized by negative to low positive εHf(t) values (from-1.0 to +6.3) and old model ages (T DM) (with the T DM1 from 874 to 597 Ma and T DM2 from 1,298 to 833 Ma). In contrast, the Halong granite has an emplacement age of 398.3 ± 2.4 Ma and is characterized by higher positive εHf(t) values (from +9.9 to +15.2) and younger model ages (T DM) (with the T DM1 from 626 to 414 Ma and T DM2 from 760 to 423 Ma). They all have intruded into the Kulumuti group stratum, which has negative initial εNd(t) values (from-4.3 to-0.2) and old T DM model ages (between 1.22 and 1.56 Ga). Based on the calculated results of the mixing ratios (f) of the initial magmas and the prevailing Paleozoic tectonic framework of the Chinese Altay, we establish two petrogenetic models for the K-A-J pegmatites: Model 1 refers to that these pegmatites originated from a mixed magma that was composed of 72 wt.% to 91 wt.% depleted mantle components and 9 wt.% to 28 wt.% lower crust components; and Model 2 refers to that they were derived from the partial melting of 38 wt.% to 83 wt.% Halong granite and 17 wt.% to 62 wt.% sedimentary rocks from the Kulumuti group. We also suggest that the initial magma of the Halong granite was significantly contributed by juvenile materials with a slight involvement of crustal materials. In Model 1, because LCT-type pegmatites (classified as Li-Cs-Ta enriched pegmatites associated with S-type granite that was produced by the partial melting of preexisting sedimentary rocks) have close geochemical affinities with crustal materials, the excessively high weight percentages (72 wt.% to 91 wt.%) of the depleted mantle components in the initial magma of the K-A-J pegmatites indicate that this model is unrealistic. Therefore, we consider that Model 2 is more reasonable at present for interpreting the petrogenesis of the K-A-J pegmatites, and it needs to be verified in other pegmatite fields of the Chinese Altay.

h i g h l i g h t s• Fe/Al-Lap catalysts with mesoporous structure were synthesized.• Iron oxide mainly exists in form of isolate Fe 3+ in an oxidic environment.• Fe/Al-Lap catalysts show high catalytic activities at low temperature.• The high catalytic activities are ascribed to the interaction between iron oxide and alumina.• The formed Fe 2 (SO 4 ) 3 and elemental sulfur deposits on surface cause catalyst deactivation. g r a p h i c a l a b s t r a c tThe catalytic reaction and deactivation mechanisms for H 2 S selective oxidation over Fe/Al-Lap catalysts are shown in the illustration. The catalytic reaction follows Mars-van Krevelen mechanism. Moreover, the interaction between iron oxide and alumina, the strong acidity of the catalysts and the well dispersion of iron oxide improve the catalytic performance efficiently. Meanwhile, the catalyst deactivation is mainly due to the formation of Fe 2 (SO 4 ) 3 and elemental sulfur deposits on the surface. a r t i c l e i n f o b s t r a c tA series of iron oxide supported on alumina-intercalated clay catalysts (named Fe/Al-Lap catalysts) with mesoporous structure and high specific surface area were prepared. The structural and chemical properties were studied by nitrogen sorption isotherms, X-ray diffraction (XRD), UV-vis diffuse reflectance spectra (UV-vis DRS), X-ray photoelectron spectra (XPS), Fourier transform infrared spectroscopy (FTIR), H 2 temperature-programmed reduction (H 2 -TPR) and NH 3 temperature-programmed desorption (NH 3 -TPD) techniques. It was realized that iron oxide mainly existed in the form of isolated Fe 3+ in an oxidic environment. Fe/Al-Lap catalysts showed high catalytic activities in the temperature range of 120-200 • C without the presence of excessive O 2 . This can be attributed to the interaction between iron oxide and alumina, which improve the redox property of Fe 3+ efficiently. In addition, the strong acidity of catalysts and good dispersion of iron oxide were also beneficial to oxidation reaction. Among them, 7% Fe/AlLap catalyst presented the best catalytic performance at 180 • C. Finally, the catalytic and deactivation mechanisms were explored.Crown

We report a cerium metal-organic framework (ZJU-136-Ce) for the turn-on fluorescence sensing of AA. The fluorescence enhancement is attributed to the specific redox reaction between AA and Ce. The detection limit of AA reaches 7 nM, showing its potential for AA detection in the environmental industry and clinical medicine.