Engineering of Mn3O4@Ag microspheres assembled from nanosheets for superior O3 decomposition.

Manganese oxides have wide application in the ambient decomposition of ozone, although their activities are affected by many parameters. Morphology engineering and metal doping are, together, one of the most effective methods to enhance catalytic activity for O3 decomposition. Herein, a topochemical transformation route to Mn3O4 nanospheres composed of 2D nanosheets is first provided by using layered ß-MnOOH as the precursor. Then, silver nanoparticles are deposited over the Mn3O4 nanosheets via a redox reaction without any extra reducing agents. In comparison with Mn3O4 with a conventional octahedral morphology, the prepared Mn3O4 nanosphere (Mn3O4-NF), and its Ag-doped composite, Mn3O4@Ag (Mn3O4@Ag-NF), both retain the morphology of ß-MnOOH, and display better reducibility and higher oxygen vacancies. The best catalytic performance for O3 decomposition is found over Mn3O4@Ag-NF, which exhibits ∼88.5% removal efficiency within 24 h at a space velocity of 600 L g-1 h-1 and a relative humidity of 50% at room temperature. This work emphasizes the advantages of nanosheet morphology and metal doping in optimizing the catalytic activity for O3 elimination of manganese oxide.

Oxygen Defect Engineering of ß-MnO2 Catalysts via Phase Transformation for Selective Catalytic Reduction of NO.

The catalysts for low-temperature selective catalytic reduction of NO with NH3 (NH3 -SCR) are highly desired due to the large demand in industrial furnaces. The characteristic of low-temperature requires the catalyst with rich active sites especially the redox sites. Herein, the authors obtain oxygen defect-rich ß-MnO2 from a crystal phase transformation process during air calcination, by which the as-prepared γ-MnO2 nanosheet and nanorod can be conformally transformed into the corresponding ß-MnO2 . Simultaneously, this transformation accompanies oxygen defects modulation resulted from lattice rearrangement. The most active ß-MnO2 nanosheet with plentiful oxygen defects shows a high efficiency of > 90% NO conversion in an extremely wide operation window of ≈120-350 °C. The detailed characterizations and density functional theory (DFT) calculations reveal that the introduction of oxygen defects enhances the adsorption properties for reactants and decreases the energy barriers of *NH2 formation more than 0.3 eV (≈0.32-0.37 eV), which contributes to a high efficiency of low-temperature SCR activity. The authors finding provides a feasible approach to achieve the oxygen defect engineering and gains insight into manganese-based catalysts for low-temperature NO removal or pre-oxidation.

Fabrication and catalytic tests of MCM-22/silicon carbide structured catalysts.

The structured catalyst of zeolite MCM-22/silicon carbide (SiC) was prepared for the first time through the in situ hydrothermal synthesis approach. The zeolite loading of the structured catalyst could be tuned by changing the synthesis time and applying alkali pre-treatment of SiC substrate. An additional silica layer formed on SiC substrate after the precalcination treatment facilitated the crystallization of MCM-22 zeolite on the SiC substrate. The MCM-22/SiC structured catalyst thus prepared exhibited good catalytic performance in the methane dehydroaromatization reaction.

[Progress on application of traditional Chinese medicine in hemopoietic stem cell transplantation].

The pertinent literature on application of traditional Chinese medicine (TCM) in hemopoietic stem cell transplantation was summarized, it indicated that the intervention of TCM could raise the mobilization effect, speed up the hemopoiesis and immunologic reconstruction after transplantation, decrease the incidence of complications, and prolong the life span of patients, showing a preliminary achievement.

[Pretreatment of lead-antimony alloy and determination of antimony and selenium using ICP-AES].

The sample was obtained from original sample using "sawing method" and was dissolved with a mixed solvent of nitric acid and tartaric acid. After the sample solution was pretreated with a series of methods, Sb and Se were determined by inductively coupled plasma atomic emission spectrometry (ICP-AES). The results show that the recovery of standard addition of Sb was 96.2% and that of Se was 92.1%, and that the relative standard deviations (n=11) were smaller than 3.56%. The method is efficient, accurate and easy to operate, and has been applied to the determination of Sb and Se in Pb-Sb alloy products with satisfactory results.

[Determination of twenty one elements in lithium hexafluorophosphate by ICP-AES].

One gram (+/- 0.0001 g) of lithium hexafluorophosphate was weighed exactly under dry atmosphere and was dissolved with an adequate amount of dimethyl carbonate (DMC). After the sample solution was pretreated with a series of methods, Be, Cu, Pb, Ca, Zr, Co, Mg, V, Ti, Mo, Ni, Mn, Sr, Zn, K, Al, Ba, Cd, Fe, Cr and Na were determined by ICP-AES. The results show that the recoveries of standard addition were 93.3%-102.1%, and the relative standard deviations (n = 11) were 0%-3.56%. The method is efficient, accurate and easy to operate. It has been applied to the determination of lithium hexafluorophosphate products with satisfactory results.

[Determination of Se in serum by ICP-AES].

The serum sample solution was prepared by using acid digestion and the Se concentration in it was determined by ICP-AES. At the same time, the interference from Fe and the interference-free method were studied. The results showed that the recovery of standard addition was 91.6%, the relative standard deviation(n = 10) was 2.147% and when KOH was added to the sample solution the interference was reduced greatly. The method is efficient, accurate and easy to operate.