Y.H. Sun

A catalyst with high activity and selectivity for the synthesis of C2+-OH: ADM catalyst modified by nickel

For ADM catalyst, Ni was an effective promoter for the activity, in particular C2+-OH selectivity. At a Ni/Mo molar ratio of 0.5, the highest ratio of C2+-OH/C1-OH (8.75) was obtained, which was about 10 times that of ADM catalyst in the absence of Ni (0.87). The modification of Ni showed remarkable structural effects and the great deviation of methanol from the linear A-S-F distribution indicated a different reaction route, which might be caused by the bi-functionality of nickel species, namely, the formation of corresponding precursor of alcohol and the strong ability of CO insertion.

The structure and reactivity of coprecipitated Co-ZrO2 catalysts for Fischer-Tropsch synthesis

The co-precipitated Co-ZrO2 catalysts of varying composition were investigated with BET, XRD, TPR and IR. For the low Co content catalysts, the cobalt existed as highly dispersed species, which led to low extent of reduction and favored CH4 formation. For the high Co coment catalysts, the reduction degree reached to 100% and improvement of Fisher-Tropsch synthesis was observed. The performance was closely related to the reducibility of catalysts.

Moderate salt treatment alleviates ultraviolet-B radiation caused impairment in poplar plants.

The effects of moderate salinity on the responses of woody plants to UV-B radiation were investigated using two Populus species (Populus alba and Populus russkii). Under UV-B radiation, moderate salinity reduced the oxidation pressure in both species, as indicated by lower levels of cellular H2O2 and membrane peroxidation, and weakened the inhibition of photochemical efficiency expressed by O-J-I-P changes. UV-B-induced DNA lesions in chloroplast and nucleus were alleviated by salinity, which could be explained by the higher expression levels of DNA repair system genes under UV-B&salt condition, such as the PHR, DDB2, and MutSα genes. The salt-induced increase in organic osmolytes proline and glycine betaine, afforded more efficient protection against UV-B radiation. Therefore moderate salinity induced cross-tolerance to UV-B stress in poplar plants. It is thus suggested that woody plants growing in moderate salted condition would be less affected by enhanced UV-B radiation than plants growing in the absence of salt. Our results also showed that UV-B signal genes in poplar plants PaCOP1, PaSTO and PaSTH2 were quickly responding to UV-B radiation, but not to salt. The transcripts of PaHY5 and its downstream pathway genes (PaCHS1, PaCHS4, PaFLS1 and PaFLS2) were differently up-regulated by these treatments, but the flavonoid compounds were not involved in the cross-tolerance since their concentration increased to the same extent in both UV-B and combined stresses.

Effect of impregnation pH on the catalytic performance of Co/ZrO2 catalyst in Fischer-Tropsch synthesis

A series of Co/ZrO2 catalysts were prepared by controlling the pH value of the cobalt nitrate solution. The interaction of cobalt precursor and ZrO2 support showed to be dependent on the impregnation pH and then influenced the catalytic activity of the Co/ZrO2 catalysts in Fischer-Tropsch synthesis.

Synthesis and characterization of mesoporous aluminosilicates from zeolitic precursors and TEOS

Mesoporous aluminosilicates with improved hydrothermal stability were prepared via the controlled coassembly of zeolitic precursors and TEOS in alkaline media. XRD, N 2 sorption, and TEM methods showed that the coassembled sample had hexagonal mesostructures, and the hydrothermal stability was largely improved compared to normal MCM-41. 29 Si MAS NMR spectra indicated that the product had higher cross-linking degree compared to normal MCM-41 through the extra introduction of protozeolitic nanoclusters. 27 Al MAS NMR spectra implied that most Al species had been tetrahedrally incorporated into the framework. The catalytic cracking conversion rate of 1,3,5-triisopropylbenzene over this sample was as high as 97.66%. At the same time, the hydrolysis behavior of TEOS and synergic polymerization process of protozeolitic nanoclusters and silicate oligomers were outlined.

Different tolerance mechanism to alkaline stresses between Populus bolleana and its desert relative Populus euphratica

Background and aimsPopulus bolleana Lauche. (P. bolleana) and Populus euphratica Oliv. (P. euphratica) separately survive in mild and moderate alkaline soil conditions. The aim of this study was to explore the underlying mechanism for the different alkaline tolerance in the two poplar species.MethodsYoung saplings of two poplar species were grown in moderate alkaline soil, and the young and old leaves of the two poplars were separately analyzed by ion concentration, allocation and distribution, transcript variation of different genes involved in ion transport and nitrogen assimilation, nitrogen metabolism, organic acid, leaf pigments, and redox responses.ResultsExcess Na+ under alkali stress was mainly allocated to old leaves in P. bolleana. However, excess Na+ was allocated to both young and old leaves in P. euphratica, and was balanced by enhanced levels of Mg2+, Ca2+, and SO42−, with no change in oxidative parameter. The reduction of nitrate nitrogen occurred under alkali stress in both species; P. euphratica acclimated to alkali stress by more flexible regulation of N metabolism and nitrate absorption than P. bolleana.ConclusionsOur results strongly indicated different alkali tolerance mechanisms in P. bolleana and P. euphratica. P. bolleana protects young tissues via profound accumulation of Na+ and confining damage effects into the old leaves under alkali stress, while P. euphratica can effectively compartmentalize excess Na+, keep its ion balance, and adjust nitrogen transport and metabolism in both young and old leaves to avoid alkali damage.

Two-step route to acid AIMSU-X mesostructures templated by neutral TX-100

Abstract Strong acid AlMSU-X mesostructures with narrow pore size distribution and large surface areas have been prepared from performed beta nanoclusters in the presence of nonionic TX-100 as the structure director through a N 0 (N + )XT + pathway in extremely acidic media. XRD, N 2 sorption, TEM, 27 Al MAS NMR, NH 3 -TPD and catalytic test reaction have been applied to characterize the products. The results obtained by these methods indicated aluminum had been successfully incorporated into the mesostructrue framework.

Infrared study of CO and CO/H2 adsorption on copper catalysts supported on zirconia polymorphs

Abstract Cu/ZrO 2 catalysts prepared with different zirconia polymorphs as supports were characterized by FT-IR technique to determine the effect of zirconia polymorphs on methanol synthesis from CO hydrogenation. The results showed that the zirconia polymorphs impacted greatly influence on copper state and behavior of CO adsorption. Simultaneously, the formation of intermediate species and methanol were also affected by zirconia polymorphs.

RESEARCH ON THE KNOWLEDGE ENGINEERING FOR CATALYST DESIGN

Practice in catalyst design shows its dependence on both catalytic knowledge and knowledge processing. To a special catalyst design problem, the organization of knowledge needs consideration on all types of available knowledge due to the complexity of catalysis science and engineering. Computer application can facilitate the knowledge processing in the design of a catalyst. The expert system integrated with numerical programs proved to be efficient for oriented catalyst design.

ESTRECAP___A GENERAL PROGRAM FOR COMPUTER-AIDED CATALYST PELLET DESIGN

A program, ESTRECAP (Exact Solution of Transfer and REaction in CAtalyst Pellets), has been developed for solving transfer-reaction model of catalyst pellet. In the program, activity distribution was expressed by the normal function and deactivation is considered in a simplified way. It has been proved that the program is very flexible and can obtain all the solutions in the multiplicity region.