A novel synthesis and characterization of ordered meso/macroporous alumina with hierarchical and adjustable pore size.

The sub-micron polystyrene (PS) microspheres with adjustable size were firstly synthesized using emulsion polymerization method by adding only a small amount of emulsifier. Then, three dimensionally ordered macroporous alumina with mesoporous walls and adjustable macropore size was facilely prepared by the colloidal template method. The alumina and PS spheres were characterized by nanoparticle size analyzer, SEM, XRD and N2 adsorption. The results show that the polystyrene microsphere has adjustable single-sized pore with diameter in the range of 100-350 nm and the yield is higher than that prepared by soap free emulsion polymerization. The alumina materials as prepared using the PS colloidal crystals as the template, had ordered meso-macroporous structures and adjustable apertures. The mesopores (about 3.6 nm) in γ-alumina were formed by controlling the heat treatment of alumina precursor. BET surface area and pore volume of the hierarchical alumina as obtained can reach to 241.3 m2/g and 0.33 cm3/g, respectively.

A critical review on the heterogeneous catalytic oxidation of elemental mercury in flue gases.

Nowadays, an increasing attention has been paid to the technologies for removing mercury from flue gases. Up to date, no optimal technology that can be broadly applied exists, but the heterogeneous catalytic oxidation of mercury is considered as a promising approach. Based on a brief introduction of the pros and cons of traditional existing technologies, a critical review on the recent advances in heterogeneous catalytic oxidation of elemental mercury is provided. In this contribution, four types of Hg oxidation catalysts including noble metals, selective catalytic reduction (SCR) catalysts, transition metals, and fly ash have been summarized. Both the advantages and disadvantages of these catalysts are described in detail. The influence of various acidic gases including SO2, SO3, NH3, NOx, HCl, Cl2, etc. have been discussed as well. We expect this work will shed light on the development of heterogeneous catalytic oxidation of elemental mercury technology in flue gases, particularly the synthesis of novel and highly efficient Hg(0) oxidation catalysts.

Ensemble and ligand effects on the acetylene adsorption on ordered Pd(x)Ag(1-x)/Pd(100) surface alloys investigated by periodic DFT study.

The interactions of acetylene with structurally ordered PdxAg1-x/Pd(100) (x = 1, 0.75, 0.5, 0.25) surface alloys, in which Ag is presented only in the first layer as the computational model system, were investigated by gradient corrected periodic density functional calculations to unravel and understand contributions from electronic strain, electronic ligand and geometric ensemble effects. The calculated adsorption energies indicate that the hollow sites are always found to be more stable than any others and more sensitive to the Ag atoms because of the strong ensemble effect. However, the ligand effect plays a significant role in both the top and bridge adsorption sites. The electrons transferred to the acetylene molecules from the surface increase with increasing concentration of the surface atomic Ag.

miR-29 regulates metabolism by inhibiting JNK-1 expression in non-obese patients with type 2 diabetes mellitus and NAFLD.

Previous studies have shown that microRNAs (miRNAs) are involved in the regulation of a variety of metabolic diseases, which related to some important signal pathways. Our aim was to explore the possible mechanism of miRNAs by revealing the differential expression of serum miRNAs in different BMI of type 2 diabetes mellitus (T2DM) patients with non-alcoholic fatty liver disease (NAFLD). We found that miR-29 decreased liver aminotransferase gamma-GGT and uric acid levels by inhibiting the expression of JNK-1 in non-obese T2DM patients with NAFLD, and down-regulated the expression of atherosclerosis-related factor lipoprotein phospholipase A2 (Lp-PLA2). Combined with bioinformatics analysis, we speculate that this may be mediated by the AMPK signaling. These findings suggest that miR-29 may be a potential targeted therapeutic strategy in T2DM patients with NAFLD.

Mass Transfer Behavior of Benzene in Hierarchically Structured ZSM-5.

A series of ZSM-5 zeolites with hierarchical porous structure were synthesized using NaOH solutions treatment method. The structural and acidity properties of hierarchical ZSM-5 zeolites as-synthesized were characterized by X-ray diffraction (XRD), N2 adsorption, scanning electron microscope (SEM), NH3-temperature programmed desorption (TPD), and pyridine Fourier transform infrared spectroscopy (Py-FTIR). The adsorption and diffusion performances of benzene in hierarchical ZSM-5 zeolites were studied by an intelligent gravimetric analyzer (IGA). It was found that mass transfer (adsorption and diffusion) performance of benzene was significantly affected by synergetic effect of hierarchical structure, acid amount, acidity, adsorption sites of ZSM-5 zeolites. After suitable alkali treatment, the crystal structure of ZSM-5 was retained and finely tailored. Hierarchical ZSM-5 was obtained with a uniform size of mesoporous and microporous structure. Acidity of hierarchical ZSM-5 zeolites was improved, which produced more adsorption sites and thus increased the adsorption performance of benzene in hierarchical ZSM-5. As a result, connectivity in hierarchical ZSM-5 was improved with increasing of mesopores in hierarchical ZSM-5. Hierarchical ZSM-5 well-contributed to the adsorption performance of benzene on active sites and improved catalytic performance of hierarchical ZSM-5.

Highly Efficient Liquid-Phase Hydrogenation of Naringin Using a Recyclable Pd/C Catalyst.

A highly efficient liquid-phase hydrogenation reaction using a recyclable palladium on carbon (Pd/C) catalyst has been used for the transformation of naringin to its corresponding dihydrochalcone. The effects of various solvents on the hydrogenation process were studied, with water being identified as the optimal solvent. The analysis also revealed that sodium hydroxide (NaOH) can accumulate on the surface of the Pd/C catalyst in alcoholic solvents, leading to its inactivation. The higher solubility of NaOH in water implies that it remains in solution and does not accumulate on the Pd/C catalyst surface, ensuring the catalytic activity and stability.

Enhanced solar absorption and visible-light photocatalytic and photoelectrochemical properties of aluminium-reduced BaTiO3 nanoparticles.

Enhanced solar light absorption and photocatalytic and photoelectrochemical properties have been achieved in black BaTiO3 with a unique core/shell structure (crystalline BaTiO3@amorphous BaTiO3-x) using an Al-reduction method. This finding may open a new avenue to tune the inert ferroelectric materials toward excellent photocatalysts for advanced applications.

Density functional theory studies of the palladium-silver(211) stepped surfaces.

Twenty-five kinds of Palladium-silver alloy stepped surface models are established based on the pure Pd(211) stepped surface system. The surface energies, work function, d-band center and the d-band local density of states (d-LDOS) on these different Palladium-silver alloy stepped surface configurations were investigated using the generalized gradient approximation (GGA) of density functional theory (DFT). The calculation results show that both the concentration and position of the doped Ag atoms have effect on these four surface parameters. The surface stability is weakened with increase of the concentration of the doped Ag atoms. The work function is more sensitive to the position of Ag atoms than the Ag concentration, while the surface energy is more depended on the Ag concentration. The substitution of Pd atoms by Ag on the pure Pd(211) stepped surface leads to the reduction of the work function. On the other hand, the d-band center of the surface Pd atoms shifts to the Fermi energy level when the Ag atoms substitute the Pd atoms in the third layer. Furthermore, the magnitude of the surface Pd d-band center increases with the content of Ag atoms from the bottom to the top along the stepped surface, and the bonding activity of the surface Pd atoms enhances. The further d-LDOS analysis shows that the Pd d-electronic structure changed with the substitution by Ag atoms on the stepped surface.

Surface acidity effects of Al-SBA-15 mesoporous materials on adsorptive desulfurization.

SBA-15 and Aluminum-substituted SBA-15 with Si/Al molar ratio 10 (Al-SBA-15(10)) mesoporous materials were directly synthesized by a hydrolysis approach and characterized by a powder X-ray diffraction (XRD), N2 physisorption analysis and Fourier transform infrared (FTIR) etc. The relative number of hydroxyl groups was investigated by in situ FTIR systematically. The acid type and acid strength of the adsorbents were monitord by FTIR at 423 K and 673 K, respectively, utilizing pyridine as a probe. Desulfurization performances of the adsorbents were investigated via static adsorption experiment. Gas chromatography-sulfur chemiluminescence detector (GC-SCD) was employed to detect the sulfur compounds in model fuels before and after treated by the adsorbents. The calcined Al-SBA-15(10) material shows well-ordered hexagonal mesostructure and strong Lewis acid sites (L acid) and weak Brönsted acid sites (B acid). The number of hydroxy on the surface of the Al-SBA-15(10) is more than that of SBA-15, which is beneficial to further modifications such as spontaneous monolayer dispersion. Desulfurization performance of the adsorbents is affected by surface acidity of adsorbents and the constituent of model fuels (olefins, arene, etc.). The thiophene and olefins adsorbed on the B acid site of the adsorbent may occur subsequently alkylation reactions, which may block the pores of the adsorbents and thus cause the reduction of desulfurization capacity.