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Mechanisms and kinetics for the reduction of a precipitated iron-based Fischer–Tropsch catalyst in H 2 have been investigated using in situ Mossbauer effect spectroscopy (MES) and thermogravimetric (TG) method in the temperature range of 250–350 °C. In situ MES results indicate that the reduction of paramagnetic (PM) α-Fe 2 O 3 (70%) and superparamagnetic (spm) Fe 3+ (30%) in the fresh catalyst proceed via different steps. PM α-Fe 2 O 3 is firstly reduced to magnetite and then to metallic iron, while the reduction of spm Fe 3+ proceeds in three consecutive steps: it is first reduced to magnetite with a significantly rapid rate, then to non-stoichiometric wustite, and finally to metallic iron. The reduction of PM α-Fe 2 O 3 to Fe 3 O 4 can be described by a two-dimensional Avrami–Erofe’ ev phase change model (formation and growth of nuclei). However, the corresponding overall reduction, which includes the reduction of PM α-Fe 2 O 3 and spm Fe 3+ to Fe 3 O 4 , can be described by a three-dimensional phase-boundary-controlled reaction model based on the overall extraction ratio of oxygen. The difference between the two models selected for the PM α-Fe 2 O 3 reduction and the corresponding overall reduction is attributed to the rapid reduction of spm Fe 3+ to Fe 3 O 4 . For the reduction of PM magnetite to α-Fe and its corresponding overall reduction (including the reduction of PM and spm Fe 3 O 4 to α-Fe), it is found that both of them follow the Avrami–Erofe’ ev phase change model (two-dimensional or three-dimensional). The value of apparent activation energy for the overall reduction has been calculated and compared with the literature data.

Cu/ZnO/Al2O3 methanol synthesis catalysts prepared by gel-oxalate co-precipitation method are found to be highly influenced by the calcination conditions. The structure and morphology of the catalysts were studied by nitrogen physisorption, N2O decomposition adsorption, TEM, and XRD. The results show that the decomposition mechanism of catalyst precursors are quite different under different calcination conditions. Mild calcination processing and oxygen-rich atmospheres are proper calcination conditions for obtaining a high performance ultrafine Cu/ZnO/Al2O3 methanol synthesis catalyst.

According to the features of CuC2O4·H2O and the colloid/precipitation theories, a practical approach for the preparation of Cu/ZnO-based catalyst, which had high activity for methanol synthesis, was proposed and verified in experiments. Co-precipitation reaction in the ethanol solution was found to be an effective route for the preparation of a highly active and selective catalyst. The characterization of XRD, N2 physisorption, TEM and the measurement of the copper surface area by nitrous oxide titration revealed that preparation conditions have a significant influence on the structure and surface properties of the precursors and the catalysts, as well as on the catalytic activities for methanol synthesis from CO2 hydrogenation.

New heteroleptic tris-cyclometalated iridium(III) complexes (ppy)2 Ir(LX) (ppy==2-phenylpyridine, LX==Sal (salicylic acid), Msal (4-methylsalicylic acid), FSal(4-trifluoro methyl salicylic acid)) was synthesized and characterized. The molecular structure, photophysical properties and thermal stability were tested and analyzed. The results show that the absorption peaks were located around 270, 370, 450 and 484 nm respectively at room temperature. The two former peaks at 270 and 370 nm should belong to 1pi--pi* transition at ppy and transition from salicylic acid ligands to 2-phenylpyridine; The peaks around 450 and 484 nm can be assigned to the charge transfer transition from Ir to ligand (1MLCT and 3MLCT) and 3pi--pi* transition respectively. The PL emission peaks were located at 520, 522, and 510 nm, respectively. The emission of (ppy), Ir(Sal) and (ppy), Ir (MSal) was mainly ascribed to the radiation transition of triple state 3MLCT, while the emission of (ppy)2 Ir(FSal) was mainly from the radiation transition between Sal and ppy, partly from the radiation transition of single state 1MLCT and triple state 3MLCT. The quantum efficiencies of these complexes were 0.37, 0.33 and 0.29 respectively. The thermal decomposition temperature was from 306 to 328 degrees C. (ppy)2 Ir(LX), being a series of efficient phosphorescent materials with good thermal stability, can be used in the organic electroluminescent devices.

A new type organic electroluminescent device with interinserting interface was fabricated. The basic structure of the device is ITO/NPB/Alq3/Al. By tailor-made template, the two interinserting interfaces were fabricated with NPB/Alq3 and Alq3/Al, respectively. The charge distribution on the interface and the electric field distribution in the organic layer were changed by introducing interinserting interfaces, thus the electron injection was improved, and the balance of the number of the electrons and holes at the interface was obtained. Therefore, the formation probability of exciton was enhanced and the leakage current was reduced. Compared to the traditional two-layer structure devices, the interinserting structure device has lower turn-on voltage and higher luminous efficiency. The driving-voltage of the interinserting structure OELD decreased while the brightness increased with the increase in the number of the interinsertion. As the current density increased, all the devices with interinserting interface showed high optical-electrical stability. The turn-on voltage of the device e is 3 V, and was made using the three slots template. At the current density of 54 mA x cm(-2), the device e gets its maximum efficiency, which is 34% higher than the traditional structure device a.

A ligand 5,5'-methylene-bis(8-hydroxyquinoline)(Hqq) was synthesized by condensation reaction at low temperature and was subsequently coordinated to gallium ions to prepare the polymer of tis(5,5'-methylene-bis(8-hydroxyquinoline) gallium (Gaqq3)n. Both chemical structure and phase structure of the ligand and complexes were characterized by Infrared absorption spectrum and X-ray diffraction (XRD). The thermal stability of the complexes was studied by thermogravimetry (TG). The photo-physical properties of the complexes were investigated by ultraviolet absorption spectrum (UV), fluorescence excitation spectrum and emission spectrum. The result indicated that (Gaqq3)n is a thermally stable material, whose decomposition temperature is 443.6 degrees C. The ultraviolet absorption bands of (Gaqq3)n are in the range of 250-500 nm, with a relatively strong band tail absorption between 500 and 650 nm, which shows that the band-gap defect states exists in the forbidden band. The fluorescence excitation band of (Gaqq3)n is located at 380-456 nm, and (Gaqq3)n. emits orange-red fluorescence with the emission peak at 568 nm, which shows that the fluorescence emission of (Gaqq3), is mainly attributed to the charge transfer transitions from phenol to ring pyridine ring, while the pi--pi* transition of benzene ring is deactivated by non-radiative transition, and makes no contribution to fluorescence emission. (Gaqq3)n optical band gap is 2.49 eV. Compared with the fluorescence emission peak of Gaq3, the fluorescence intensity of (Gaqq3), decreases, which is attributed to the distortion of the two quinoline rings connected to the methylene, hence leads to the poor rigidity and coplanarity of (Gaqq3)n, thus affects fluorescence emission intensity. Because of the extending of the molecular conjugation system, pi electron of (Gaqq3)n is more delocalized, resulting in the redshift of fluorescence emission peak (Gaqq3)n is expected to be applied in organic light emitting display and organic photovoltaic devices.

In this article we will introduce a Light Emitting Diode (LED) lighting diffuser plate which diffuses light by optical microstructure. In LED lighting, LED array is the most popular method to attain the illuminance requirement, but this method will produce the glaring and non-uniform illuminance problems. Traditionally, diffuser, which is comprised of diffuser particles, is used to solve the above problems, but it also produces another problem which is low lighting efficiency. Therefore, we use optical microstructure to replace the diffuser particles to solve the problems of LED lighting but only reduce a little lighting efficiency. Moreover, we could control the lighting area of the LED lamp by designing the optical microstructure.

Iridium (III) complexes with 2-phenylpyridine (ppy) have been demonstrated as a type of promising phosphorescence dopant in emitting layers of organic light emitting diodes (OLEDs). In most iridium (III) complexes, there exist the strong spin-orbit coupling between π-orbitals of cyclometalated ligands and 5d orbitals of the centric iridium. We study a novel iridium (III) complex (ppy)2Ir(4-TfmBTZ) with ppy as cyclometalated ligands and 2-(4-trifluoromethyl-2-hydroxylphenyl)benzothiazole (4-TfmBTZ) as an ancillary ligand using the Gaussian 03 program. The geometries, electronic structures and spectroscopic properties of this iridium (III) complex are investigated by density functional theory (DFT) and time-dependent density functional theory (TD-DFT). The results show that the spin-orbit coupling occurs not only between ppy and iridium atom but also between 4-TfmBTZ and iridium atom in this complex. The highest occupied molecular orbital is dominantly localized on the Ir atom and 4-TfmBTZ ligand, while the lowest unoccupied molecular orbital on 4-TfmBTZ ligand. The triplet lowest-lying transition is attributed to the Ir-to-4-TfmBTZ charge-transfer (3MLCT) transition while the sub-low-lying transitions are assigned to the 3MLCT transitions of Ir(ppy)2. The nature of the lowest unoccupied orbital changes from ppy-localized to 4-TfmBTZ-localized and reveals that phosphorescent color of Ir(III) complex can be controlled by the ancillary ligand and substituent.