Theoretical Study for Adsorption-Diffusion on H-MOR and Pyridine Pre-adsorbed H-MOR of Dimethyl Ether Carbonylation.

For dimethyl ether (DME) carbonylation, pyridine pre-adsorbed hydrogen mordenite (H-MOR) is beneficial to prolonging the catalyst life. The adsorption and diffusion behaviors on periodic models H-AlMOR and H-AlMOR-Py were simulated. The simulation was based on Monte Carlo and molecular dynamics.

Synthesis of methanol over highly dispersed Cu-Fe based catalysts derived from layered double hydroxides.

In this paper, catalysts with different aluminum contents were prepared by a co-precipitation method using LDHs (layered double hydroxides) as the precursors through the adjustment of Cu : Fe, and the catalysts were named LDO catalysts. The effect of aluminum on CO hydrogenation to methanol was investigated by evaluating the characterization. With the addition of Al, Ar physisorption results showed an increase in BET-specific surface area, TEM demonstrated a decrease in catalyst particle diameter, XRD showed that Cu and Fe existed in the catalyst mainly in the form of CuFeO and CuO, XPS demonstrated a decrease in electron cloud density and an increase in base sites and oxygen vacancies, and CO-TPD and H-TPD results indicated that Al promoted the dissociation and adsorption of CO and H.

Utilization of SAPO-18 or SAPO-35 in the bifunctional catalyst for the direct conversion of syngas to light olefins.

SAPO-18 and SAPO-35 were synthesized and utilized as the zeotype in the bifunctional catalyst for the STO process, respectively. SEM and Ar physisorption proved that SAPO-18 displayed abundant outer cages, and facilitated the diffusion of the reactant and products. NH-TPD revealed the adequate acid strength of SAPO-18, thus ZnCrO + SAPO-18 bifunctional catalyst showed high selectivity to light olefins during the whole stage of the STO process.

Direct Conversion of Syngas to Light Olefins over a ZnCrO + H-SSZ-13 Bifunctional Catalyst.

In recent years, bifunctional catalysts for the syngas-to-olefins (STO) reaction via the oxide-zeolite (OX-ZEO) strategy has been intensively investigated. However, the bifunctional catalyst containing H-SSZ-13 with a 100% H-exchanging degree for the STO reaction has not been developed because of the high selectivity to paraffin. Here, we report a ZnCrO + H-SSZ-13 bifunctional catalyst, which contains the submicron H-SSZ-13 with adequate acidic strength.

Direct Conversion of Syngas to Light Olefins through Fischer-Tropsch Synthesis over Fe-Zr Catalysts Modified with Sodium.

Fe-Zr-Na catalysts synthesized by coprecipitation and impregnation methods were implemented to investigate the promoting effects of Na and Zr on the iron-based catalyst for high-temperature Fischer-Tropsch synthesis (HTFT). The catalysts were characterized by Ar adsorption-desorption, X-ray diffraction, scanning electron microscopy, transmission electron microscopy, CO temperature-programmed desorption, H temperature-programmed desorption, X-ray photoelectron spectroscopy, and Mössbauer spectroscopy (MES). The results indicated that Na changed the active sites on the catalyst surface for the CO and hydrogen adsorption, owing to the electron migration from Na to Fe atoms, which resulted in an enhanced CO dissociative adsorption and a decrease in hydrogen adsorption on the metallic Fe surface.

Study of the Fischer-Tropsch synthesis on nano-precipitated iron-based catalysts with different particle sizes.

Nano iron-based catalysts with different particle sizes were prepared by a co-precipitated method and characterized by XRD, N adsorption, SEM, Mössbauer spectroscopy, XPS, H-TPR, CO-TPD, H-TPD and TGA. The CO-TPD results revealed that large particle sizes of catalysts were not conducive to the adsorption of CO, and exhibited low activity of FTS. The decrease of catalyst particle size enhanced the interaction between Fe and Mn, and promoted the CO chemical adsorption and the formation of FeC, but the hydrogenation reaction was inhibited as confirmed by H-TPD.

Synthesis of Submicron SSZ-13 with Tunable Acidity by the Seed-Assisted Method and Its Performance and Coking Behavior in the MTO Reaction.

Submicron SSZ-13 with different acidities was synthesized successfully with the assistance of nanosized SSZ-13 seeds. The methanol-to-olefins (MTO) properties of submicron SSZ-13 were evaluated. The lifetime of submicron SSZ-13 was enhanced because of the crystal size reduction.

Effects of Sm on Fe-Mn catalysts for Fischer-Tropsch synthesis.

Sm-promoted FeMn catalysts were prepared by the co-precipitation method and characterized by N adsorption, XRD, CO-TPD, H-TPD, CO-TPD, H-TPR, XPS and MES. It was found that compared with the un-promoted catalyst, when Sm was added at a proper content, the catalyst showed a larger BET surface area and promoted the formation of iron particles with a smaller size. The presence of Sm could increase the surface charge density of iron, which enhanced the Fe-C bond and promoted the stability and amount of CO dissociated adsorption, as confirmed by XPS and CO-TPD.

Conversion of methanol to propylene over hierarchical HZSM-5: the effect of Al spatial distribution.

Different silicon sources caused diverse Al spatial distribution in HZSM-5, and this affected the hierarchical structures and catalytic performance of desilicated zeolites. After being treated with 0.1 M NaOH, HZSM-5 zeolites synthesized with silica sol exhibited relatively widely distributed mesopores and channels, and possessed highly improved propylene selectivity and activity stability.

Biphase synthesis of a one-dimensional coordination polymer based on a dinuclear Cd(II) secondary building unit and a novel semi-rigid dicarboxylate.

A one-dimensional coordination polymer, namely catena-poly[[aquapyridinecadmium(II)]-μ(3)-{4,4'-[(2,4,6-trimethyl-1,3-phenylene)bis(methylene)]dibenzoato}], [Cd(C(25)H(22)O(4))(C(5)H(5)N)(H(2)O)](n), has been synthesized by a biphasic solvothermal reaction. The Cd(II) cation is located in a CdO(5)N six-coordinated environment. The trans 4,4'-[(2,4,6-trimethyl-1,3-phenylene)bis(methylene)]dibenzoate ligand connects the Cd(II) cations to form a one-dimensional ribbon incorporating centrosymmetric [Cd(2)(COO)(2)] secondary building units.