Europium metal organic framework (Eu-MOF) was synthesized using Europium as metal ion center and 1,3,5-trimesic acid (H3BTC) as organic ligand under hydrosolvothermal conditions. The dynamic performance of the Eu-MOF material in adsorption desulfurization processes was investigated using a solution of thiophene/n-octane as sulfur containing quality model oil. The adsorption desulfurization kinetics equations and adsorption desulfurization isotherms of Eu-MOF were also studied. The results have shown that Eu-MOF catalyst has very good adsorption desulfurization abilities under optimum desulfurization conditions of madsorbent: mmodel oil ratio of 1:100 and reaction temperature of 303 K. After 4 h of desulfurization reaction, the adsorption rate and the adsorption desulfurization capacity has reached 64.70% and 24.59 mgS/gMOF respectively. The Eu-MOF adsorption desulfurization process of thiophene on Eu-MOF fits well the quasi two level dynamic model using Langmuir isotherm, Freundlich isotherm and Dubinin–Radushkevich isotherm equations. The Dubinin–Radushkevich isotherm can be a suitable description of adsorption process for Eu-MOF absorbent on thiophene/n-octane mode oil. However the Freundlich isotherm equation model with fitting R2 value closer to 1, can be a better description for the adsorption of thiophene. The adsorption of thiophene over Eu-MOF absorbent has two types of adsorption that occur simultaneously. These are the monolayer physical adsorption and the multilayer chemical adsorption.

Magnetic Fe3O4 particles were synthesized by solvo-thermal method, and then hydrolysis method was used to encapsulate a compact layer of SiO2 on the surface of Fe3O4 particles. Finally, the magnetic MOF-5@SiO2@Fe3O4 catalysts were prepared by in situ coating different contents of MOF-5 on the surface of SiO2@Fe3O4 particles. The as-synthesized samples were characterized by TEM, SEM, XRD, FT-IR, N2 adsorption/desorption, VSM and NH3-TPD. The catalytic activities of the magnetic MOF-5@SiO2@Fe3O4 catalysts for the Friedel–Crafts alkylation of toluene with benzyl chloride were evaluated. The results showed that magnetic MOF-5@SiO2@Fe3O4 catalysts exhibited superparamagnetic property, and could be separated by a magnet from the liquid reaction system. The conversion of toluene was increased gradually with the increase of catalyst contents and reaction temperature, respectively. 97 % conversion of toluene has been achieved by using 26.8 %MOF-5@SiO2@Fe3O4 catalyst at 120 °C for 6 h. Furthermore, electron-donating group, such as –OCH3, and –CH3, exhibited positive effect on the alkylation reaction. Besides, the catalyst could be easily separated from the reaction mixture after the reaction and reused for five times without significant decrease in activity.

Metal-organic framework MIL-53(Al) was synthesized by a solvothermal method using aluminum nitrate as the aluminium source and 1,4-benzenedicarboxylic acid (H2BDC) as the organic ligand. The structure of samples was characterized by X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR). The catalytic activity and recyclability of MIL-53(Al) catalyst for the Friedel-Crafts acylation reaction of indole with benzoyl chloride were evaluated. The reaction conditions were optimized and a reaction mechanism was suggested. The results showed that the MIL-53(Al) catalyst exhibited good catalytic activity and recyclability for the Friedel-Crafts acylation reaction. When the molar ratio of indole and MIL-53(Al) catalyst was 1:0.06 (n1:ncatalyst), the molar ratio of indole and benzoyl chloride was 1:3, and the solvent was dichloromethane, the conversion of indole could reach 97.1% and the selectivity of 3-acylindole could reach 81.1% at 25 °C after 8 h. The catalyst can be reused without significant degradation in catalytic activity. After the catalyst was reused five times, the conversion of indole was 87.6% and the selectivity of 3-acylindole was 79.5%.

•Ultrasonic-assisted method was applied to synthesize meso-SiO2@Fe3O4 microspheres.•Compared to conventional method, this method involved much shorter coating time.•The silica shell of microspheres possessed desirable mesoporous structure.•The meso-SiO2@Fe3O4(E) exhibited large SBET (468.6 m2/g) and VBJH (0.35 cm3/g).•The acceleration role in coating process of mesoporous shell was investigated.A core–shell-type of meso-SiO2@Fe3O4 microsphere was synthesized via an ultrasonic-assisted surfactant-templating process using solvothermal synthesized Fe3O4 as core, tetraethoxysilane (TEOS) as silica source, and cetyltrimethyl ammonium bromide (CTAB) as templates. The samples were characterized by FT-IR, XRD, TEM, N2 adsorption–desorption technology, and vibrating sample magnetometer (VSM). The results show that as-prepared meso-SiO2@Fe3O4(E) and meso-SiO2@Fe3O4(C) microspheres, treated by acetone extraction and high temperature calcination, respectively, still maintain uniform core–shell structure with desirable mesoporous silica shell. Therein, the meso-SiO2@Fe3O4(E) microspheres possess a distinct pore size distribution in 1.8–3.0 nm with large specific surface area (468.6 m2/g) and pore volume (0.35 cm3/g). Noteworthily, the coating period of this ultrasonic-assisted method (40 min) is much shorter than that of the conventional method (12–24 h). The morphology of microspheres and the mesoporous structure of silica shell are significantly influenced by initial concentration of CTAB (CCTAB), ultrasonic irradiation power (P) and ultrasonic irradiation time (t). The acceleration roles of ultrasonic irradiation take effect during the whole coating process of mesoporous silica shell, including hydrolysis-condensation process of TEOS, co-assembly of hydrolyzed precursors and CTAB, and deposition of silica oligomers. In addition, the use of ultrasonic irradiation is favorable for improving the homogeneity of silica shell and the monodispersity of meso-SiO2@Fe3O4 microspheres.

Novel magnetic Cu-BTC@SiO2@Fe3O4 catalysts were synthesized by encapsulating magnetic SiO2@Fe3O4 nanoparticles into Cu-BTC through an in situ method. The structure of the catalysts was characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, a vibration sample magnetometer (VSM), N2 adsorption/desorption, and NH3-temperature programed desorption (NH3-TPD). The catalytic activity and recovery properties of the catalysts for the Pechmann reaction of 1-naphthol (NP) with ethyl acetoacetate (EAA) were evaluated. The results showed that the magnetic Cu-BTC@SiO2@Fe3O4 catalysts had the larger surface areas, suitable superparamagnetism, and good catalytic activity for Pechmann reaction. The conversion of 1-naphthol can reach ∼96%, and the selectivity of the production can reach ∼98% over 50.8% Cu-BTC@SiO2@Fe3O4 (MCC-10) catalyst under the reaction conditions of 130 °C and 24 h. After the reaction, the catalyst can be easily separated from the reaction mixture by an external magnet. The recovery catalyst can be reused for five times, and the conversion of 1-naphthol can be kept over 90%.

A series of magnetically recyclable Pd/Fe3O4@γ-Al2O3 catalysts were synthesized using the superparamagnetic Fe3O4@γ-Al2O3 core–shell microspheres as the supporter and nano-Pd particles assembled on γ-Al2O3 shell as the active catalytic component. The structure of the catalysts was characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), N2 adsorption–desorption and vibrating sample magnetometer (VSM). The catalytic activity and the recyclability properties of the catalysts for the Heck coupling reaction with aryl bromides and the olefins were investigated. The results show that the microspheres of the magnetic Pd/Fe3O4@γ-Al2O3 catalysts were about 400 nm and the nano-Pd particles assembled on γ-Al2O3 shell were about 3–4 nm in size. The saturation magnetization (MS) of the magnetic catalysts was sufficiently high to allow magnetic separations. In the Heck coupling reactions, the magnetic Pd/Fe3O4@γ-Al2O3 catalysts exhibited good catalytic activity and recyclability. With Pd/Fe3O4@γ-Al2O3 (0.021 mol%) catalyst, the bromobenzene conversion and product yield reached about 96.8% and 91.2%, respectively, at 120 °C and in 14 h. After being recycled for six times, the conversion of bromobenzene and the recovery of the catalyst were about 80% and 90%, respectively. The nano-Pd particles were kept well dispersed in the used Pd/Fe3O4@γ-Al2O3 catalysts.The magnetically recyclable Pd/Fe3O4@γ-Al2O3 catalysts with nanosized Pd assembled on core–shell microspheres were synthesized and the magnetic catalysts shown good activity and reusability for the Heck coupling reaction.

Ni2P/SBA-15 precursors with Ni2P loadings of 25 wt% and initial P/Ni of 0.8 were prepared using nickel nitride as nickel source, diammonium hydrogen phosphide as phosphorus and mesopore molecular sieve SBA-15 as support. Then Ce was introduced into the Ni2P/SBA-15 precursor. The novel mesoporous Ce-Ni2P/SBA-15 catalysts were prepared after temperature-programmed reduction in flowing H2. The structure was characterized by X-ray diffraction, N2 adsorption–desorption isotherms, NH3 temperature-programmed desorption and X-ray photoelectron spectroscopy. The catalytic activities for the hydrodesulfurization (HDS) of dibenzothiophene (DBT) were evaluated. The results showed that only Ni2P phase was formed in Ce-Ni2P/SAB-15 catalysts with Ce loadings of 0–5 wt%. Ni2P and Ni12P5 phases were existed in 7 wt% Ce-Ni2P/SBA-15 catalyst. The surface area and pore volume increased when Ce was added to Ni2P/SBA-15 catalyst. The strength of the acid sites and total acid amount of Ce-Ni2P/SBA-15 catalysts increased with increasing Ce loadings. Ce existed in the form of Ce3+and Ce4+, Ni existed in the form of Ni2+ and Niδ+, and P existed in the form of Pδ− and P5+. The addition of Ce to the Ni2P/SBA-15 catalyst decreased Niδ+ concentration in Ni2P/SBA-15 catalyst. The activity for HDS of DBT over Ni2P/SBA-15 catalysts was affected by the addition of Ce at 300–340 °C. The catalysts exhibited a good catalytic performance of deep hydrodesulfurization of dibenzothiophene and the conversion of DBT can reach 98.9 % at 380 °C. Biphenyl was the main product over Ce-Ni2P/SBA-15 catalysts and cyclohexylbenzene was the main product over Ni2P/SBA-15 catalyst at 380 °C.

Novel magnetically recyclable Pd/γ-AlOOH@Fe3O4 catalysts were prepared using γ-AlOOH@Fe3O4 as a magnetic supporter and nano-Pd particles as the active catalytic component. The structure of the catalysts was characterized by XRD (X-ray diffraction), TEM (transmission electron microscopy), N2 adsorption-desorption, and a VSM (vibration sample magnetometer). The catalytic activity and recyclability for the Heck coupling reaction were investigated. Results showed that the magnetic γ-AlOOH@Fe3O4 possessed a core-shell structure, as well as that the nano-Pd particles were 6–8 nm and had been well dispersed in the γ-AlOOH shell. In the Heck coupling reactions, the magnetic Pd/γ-AlOOH@Fe3O4 catalysts exhibited good catalytic activity and recyclability. For the (0.021 mol%)Pd/γ-AlOOH@Fe3O4 catalyst, the bromobenzene conversion and product yield reached about 100% and 96.3%, respectively, under a 120°C reaction temperature and 12 h reaction time. After being recycled 8 times, the conversion of bromobenzene and the recovery of the catalyst were about 90% and 93%, respectively. The nano-Pd particles were kept well dispersed in the used Pd/γ-AlOOH@Fe3O4 catalyst.

•Fe3O4 microspheres are synthesized by a CTAB-modified solvothermal process.•CTAB molecules present multifunctionality during synthesis of Fe3O4 microspheres.•The Fe3O4 exhibits narrow size distribution, monodispersity, and superparamagnetism.•The mesoporous SiO2 and sheet γ-AlOOH are directly coated on the surface of Fe3O4.•CTAB molecules can serve as nucleation seeds and templates during coating process.The Fe3O4 magnetic microspheres were prepared by a cetyltrimethyl ammonium bromide (CTAB) modified solvothermal process. Then CTAB-modified Fe3O4 microspheres were directly coated by mesoporous SiO2 and γ-AlOOH shell, respectively, and the SiO2@Fe3O4 and γ-AlOOH@Fe3O4 magnetic core–shell composites were obtained. The samples were characterized by FT-IR, XRD, Raman spectroscopy, SEM, TEM, N2 adsorption–desorption technology, and vibrating sample magnetometer (VSM). The results indicate that CTAB molecules play the roles of capping agent, dispersant, and crystal growth oriented agent during the high-temperature solvothermal process. Thus as-prepared Fe3O4 microspheres are assembled by small primary nanocrystals with uniform crystal orientation, and exhibit narrow size distribution, monodispersity, and superparamagnetism with high saturation magnetization (Ms). The formation of Fe3O4 microspheres combines oriented attachment and Ostwald ripening mechanisms. Furthermore, the adsorbed CTAB molecules can serve as nucleation seeds for precipitation of SiO2 and γ-AlOOH, and as templates for growth of mesoporous SiO2. In SiO2@Fe3O4 the mesoporous SiO2 shell presents short-range ordered pores with mean pore size of 2.1 nm. The shell of γ-AlOOH@Fe3O4 is composed of many irregular γ-AlOOH nanosheets with thickness of 3.0–5.0 nm. The BET surface areas of SiO2@Fe3O4 and γ-AlOOH@Fe3O4 reach up to 441 m2/g and 289 m2/g, respectively.

A series of AAl12O19 (A = La, Sr, Ba, Ca, Ce), AMAl11O19 (A = La, Sr; M = Cu, Mn, Fe, Ni, Mg) and Sr1−xLaxMnAl11O19 (x = 0.2–0.8) hexaaluminates were prepared successfully using urea combustion method. The influences of the molar ratio (R) of urea to the total metal ions in hexaaluminates and the urea combustion temperature on the formation of the hexaaluminates were investigated. The structure of the hexaaluminates was characterized using X-ray powder diffraction (XRD) and temperature-programmed reduction (TPR). The catalytic activity for methane combustion was evaluated. The results indicated that the preparation conditions were: for LaAl12O19, the value of R was 3, the combustion time was in the range from 40 to 60 min, and the combustion temperature was not less than 500 °C; For LaFeAl11O19 and LaMnAl11O19, the value of R was 3–7, the combustion time was 40 min, and the combustion temperature was less than 500 and 400 °C, respectively; for AAl12O19 (A = Sr, Ba, Ca, Ce), LaMAl11O19 (M = Cu, Ni, Mg), SrMAl11O19 (M = Cu, Mn, Fe, Ni, Mg) and Sr1−xLaxMnAl11O19 (x = 0.2–0.8), the value of R was 3, the combustion time was 40 min, and the combustion temperature was 500 °C. The prepared hexaaluminates had pure hexaaluminate phase structure and excellent catalytic activity in the methane combustion.A series of AAl12O19 (A = La, Sr, Ba, Ca, Ce), AMAl11O19 (A = La, Sr; M = Cu, Mn, Fe, Ni, Mg) and Sr1−xLaxMnAl11O19 hexaaluminates were prepared successfully by the urea combustion method. The prepared hexaaluminates had a pure and complete phase structure and an excellent catalytic activity for methane combustion. The method is a new, simple and environment friendly preparation method of hexaaluminates.

A series of Mo2C/SBA-15 catalysts with different Mo contents were prepared by temperature-programmed carburization (TPC). The materials obtained and their oxide precursors (MoO3/SBA-15) were characterized by Nitrogen adsorption-desorption isotherms, X-ray diffraction (XRD), and Fourier transform-infrared (FT-IR) spectroscopy. The activities of the catalysts for deep hydrodesulfurization (HDS) of thiophene were evaluated. The results of N2 adsorption-desorption isotherms indicated that the surface area and pore diameter of the oxide precursors increase after carburization. The XRD patterns show that Mo2C particles are highly dispersed in the SBA-15 ordered mesoporous. The test results show that Mo2C/SBA-15 catalysts have an excellent performance for the deep HDS under the lower temperature region.

In this work, syngas methanation over Ni-W/TiO2-SiO2 catalyst was studied in a fluidized-bed reactor (FBR) and its performance was compared with a fixed-bed reactor (FIXBR). The effects of main operating variables including feedstock gases space velocity, coke content, bed temperature and sulfur-tolerant stability of 100 h life were investigated. The structure of the catalysts was characterized by XRD, N2 adsorption-desorption and TEM. It is found that under same space velocity from 5000 h−1 to 25000 h−1 FBR gave a higher CH4 yield, lower coke content, and lower bed temperature than those obtained in FIXBR. Ni-W/TiO2-SiO2 catalyst possessed excellent sulfur-tolerant stability on the feedstock gases less than 500 ppm H2S in FBR. The carbon deposits formed on the spent catalyst were in the form of carbon fibers in FBR, while in the form of dense accumulation distribution appearance in FIXBR.

A series of Ni/SBA-15 catalysts with Ni contents ranging from 5 wt% to 15 wt%, as well as another series of 10%Ni/MgO/SBA-15 catalysts, in which the range of the MgO content was from 1 wt% to 7 wt%, were prepared, and their catalytic performances for the reaction of combined steam and carbon dioxide reforming of methane were investigated in a continuous flow microreactor. The structures of the catalysts were characterized using the XRD, H2-TPR and CO2-TPD techniques. The results indicated that the CO selectivity for this reaction was very close to 100%, and the H2/CO ratio of the product gas could be controlled by changing the H2O/CO2 molar ratio of the feed gas. The simultaneous and plentiful existing of steam and CO2 had a significant influence on the catalytic performance of the 10%Ni/SBA-15 catalyst without modification. After reacting at 850 °C for 120 h over this catalyst, the CH4 conversion dropped from 98% to 85%, and the CO2 conversion decreased from 86% to 53%. However, the 10%Ni/3%MgO/SBA-15 catalyst exhibited a much better catalytic performance, and after reacting for 620 h, the CO2 conversion over this catalyst dropped from 92% to around 77%, while the CH4 conversion was not decreased. Oxidation of the Ni0 species as well as carbon deposition during the reaction were the main reasons for the deactivation of the catalyst without modification. On the other hand, modification by the MgO promoter improved the dispersion of the Ni0 species, and enhanced the CO2 adsorption affinity which in turn depressed the occurring of carbon deposition, and thus retarded the deactivation process.

A three-dimensional geometric model was set up for the oxidative coupling of methane (OCM) fixed bed reactor loaded with Na3PO4–Mn/SiO2/cordierite monolithic catalyst, and an improved Stansch kinetic model was established to calculate the OCM reactions using the computational fluid dynamics method and Fluent software. The simulation conditions were completely the same with the experimental conditions that the volume velocity of the reactant is 80 ml·min− 1 under standard state, the CH4/O2 ratio is 3 and the temperature and pressure is 800 °C and 1 atm, respectively. The contour of the characteristic parameters in the catalyst bed was analyzed, such as the species mass fractions, temperature, the heat flux on side wall surface, pressure, fluid density and velocity. The results showed that the calculated values matched well with the experimental values on the conversion of CH4 and the selectivity of products (C2H6, C2H4, CO, CO2 and H2) in the reactor outlet with an error range of ± 4%. The mass fractions of CH4 and O2 decreased from 0.600 and 0.400 at the catalyst bed inlet to 0.445 and 0.120 at the outlet, where the mass fractions of C2H6, C2H4, CO and CO2 were 0.0245, 0.0460, 0.0537 and 0.116, respectively. Due to the existence of laminar boundary layer, the mass fraction contours of each species bent upwards in the vicinity of the boundary layer. The volume of OCM reaction was changing with the proceeding of reaction, and the total moles of products were greater than reactants. The flow field in the catalyst bed maintained constant temperature and pressure. The fluid density decreased gradually from 2.28 kg·m− 3 at the inlet of the catalyst bed to 2.18 kg·m− 3 at the outlet of the catalyst bed, while the average velocity magnitude increased from 0.108 m·s− 1 to 0.120 m·s− 1.A three-dimensional geometric model was set up for the oxidative coupling of methane (OCM) fixed bed reactor loaded with Na3PO4–Mn/SiO2/cordierite monolithic catalyst using the computational fluid dynamics method and Fluent software. The contour of the characteristic parameters in the monolithic catalyst bed, such as species mass fractions, temperature, the heat flux on side wall surface, pressure, fluid density and velocity was analyzed by an improved Stansch kinetic model.Download full-size image

A series of Pd/SiO2 and Pd/CexZr1-xO2/SiO2 (x = 0–1) catalysts with Pd loading from 0.1% to 1.0% were prepared by impregnation and characterized using X-ray powder diffraction and H2-temperature-programmed reduction. Their performance in catalytic methane combustion was evaluated in a conventional quartz reactor. The effects of CeO2 and CeZrO2 solid solutions on the performance of Pd/SiO2 were investigated. The results indicated that Pd/SiO2 exhibit good catalytic activity in methane combustion, and the addition of CexZr1-xO2 can further markedly enhance its catalytic activity. CexZr1-xO2 can promote the dispersion and reducibility of PdO in Pd/CexZr1-xO2/SiO2. The molar ratio of Ce to Zr in CexZr1-xO2 plays an important role on the catalytic activity of Pd/CexZr1-xO2/SiO2.

A dual-bed reactor was constructed comprising of a 5%Na2WO4-2%Mn/SiO2 particle catalyst and a 4%Ce-5%Na2WO4-2%Mn/SiO2/cordierite monolithic catalyst. The reaction performance of the oxidative coupling of methane (OCM) over the dual-bed reactor system was evaluated. The effects of the bed height and operation mode, as well as the reaction parameters such as reaction temperature, CH4/O2 ratio and flowrate of feed gas, on the catalytic performance were investigated. The results indicated that the suggested dual-bed reactor exhibited a good performance for the OCM reaction when the feed gases firstly passed through the particle catalyst bed and then to the monolithic catalyst bed. A CH4 conversion of 38.2% and a C2H4 selectivity of 43.3% could be obtained using the dual-bed reactor with a particle catalyst bed height of 10 mm and a monolithic catalyst bed height of 50 mm. Both the CH4 conversion and C2H4 selectivity have increased by 2.5% and 12.8%, respectively, as compared with the 5%Na2WO4-2%Mn/SiO2 particle catalyst in a conventional single-bed reactor and by 12.9% and 23.0%, respectively, as compared with the 4%Ce-5%Na2WO4-2%Mn/SiO2/cordierite monolithic catalyst in a single-bed reactor. The catalytic performance of the OCM in the dual-bed reactor system has been improved remarkably.

The core-shell structured TiO2/SiO2@Fe3O4 photocatalysts were prepared using Fe3O4 as magnetic core, tetraethoxysilane (TEOS) as silica source and tetrabutyl titanate (TBOT) as titanium sources. The as-obtained structure was composed of a SiO2@Fe3O4 core and a porous TiO2 shell. The diameter of SiO2@Fe3O4 core was about 205 nm with thickness of porous TiO2 of about 5-6 nm. The 9%TiO2/6% SiO2@Fe3O4 microspheres possess the highest BET surface area and the BJH pore volume, which are 373.5 m2·g−1 and 0.28 cm3·g−1, respectively. The 9%TiO2/6%SiO2@Fe3O4 photocatalyst exhibited an excellent performance for the degradation of methyl orange and methylene blue dyes. Two different dyes were completely decolorized in 60 min under UV irradiation. The photocatalytic activity and the amount of catalyst were almost not decrease after recycling for 6 times by using external magnetic field.

A series of Co-Ni2P/SBA-15 catalysts with various Co contents, Ni2P contents and P/Ni molar ratios were prepared by impregnating nickel nitrate, diammonium hydrogen phosphate, and then cobalt nitrate into SBA-15 support followed by temperature-programmed reduction in a H2 flow. The catalyst structure was characterized by X-ray diffraction (XRD), high resolution-transmission electron microscopy (HR-TEM) and N2 adsorption-desorption techniques and their catalytic performance of the hydrodesulfurization (HDS) of dibenzothiophene (DBT) was evaluated. The effects of Co contents, Ni2P contents and P/Ni molar ratios on the catalyst structure and HDS of DBT over the Co-Ni2P/SBA-15 catalyst were investigated. The results indicated that the mesoporous structure was mainly maintained and the nickel phosphides were well dispersed in all of the characterized catalysts. The 4Co-25Ni2P/SBA-15 (P/Ni = 0.8) catalyst with the Co and Ni2P contents of 4 wt% and 25 wt%, respectively, and the P/Ni molar ratio of 0.8 showed the highest catalytic performance for HDS of DBT. Under the reaction conditions of 380°C and 3.0 MPa, the DBT conversion can reach 99.62%. The HDS of DBT proceeded mainly via the direct desulfurization (DDS) pathway with biphenyl (BP) as the dominant product on all of the catalysts and the BP selectivity was slightly enhanced after the introduction of Co promoters.The 4Co-25Ni2P/SBA-15 (P/Ni=0.8) catalyst exhibited higher DBT conversion than the un-promoted counterpart while the catalysts with other Co contents displayed a diminished activity. An enhanced DDS selectivity was observed in all of the Co-Ni2P/SBA-15 catalysts.Download full-size image

A series of phosphorus-modified PITQ-13 catalysts was prepared by wet impregnation of NH4H2PO4 solution into an HITQ-13 parent. The catalysts were characterized using XRD, N2 adsorption, MAS NMR and NH3-TPD. Their catalytic performance in 1-butene catalytic cracking was evaluated in a fixed fluidized bed reactor. The results showed that the crystallinity, surface area and pore volume of P-modified PITQ-13 catalysts decreased with the increasing amounts of P. The number of weak acid sites increased, whereas that of strong acidity decreased. The selectivity to propylene in 1-butene cracking reactions increased because of the decrease in strong acidity. The yield of propylene achieved 41.6% over PITQ-13-2 catalyst with a P content of 1.0 wt%, which was 5.1% greater than that achieved over HITQ-13 catalyst.A series of phosphorus-modified PITQ-13 catalysts were prepared and the structure was characterized. The catalysts exhibited good performance for 1-butene catalytic cracking to the propylene.Download full-size image

AbstractA series of Ni/SBA-15 catalysts with Ni contents ranging from 5wt% to 20wt% as well as 10wt%Ni/10wt%CexZr1_x:O2/SBA-15 (x=0, 0.5, 1) were prepared. The structures of the catalysts were characterized using XR.D, TPR, TEM and BET techniques. The catalytic activities of the catalysts for steam reforming of methane were evaluated in a continuous flow microreactor. The results indicated that both the Ni/SBA-15 and the Ni/CexZr1_x;O2/SBA-15 catalysts had good catalytic activities at atmospheric pressure. The 10wt%Ni/SBA-15 catalyst exhibited excellent stability at 800 °C for time on stream of 740 h. After the reaction, carbon deposits were not formed on the surface of the catalyst. There existed a regular hexagonal mesoporous structure in the Ni/SBA-15 and the Ni/CexZr1_x;O2/SBA-15 catalysts. The nickel species and the CexZr1_x;O2 component were all confined in the SBA-15 mesopores. The CexZr1_x;O2 could promote dispersion of the nickel species in the Ni/CexZr1_x;O2/SBA-15 catalysts.

A novel particle/metal-based monolithic catalysts dual-bed reactor with beds-interspace supplementary oxygen is constructed comprising of the upper-layer 5 wt%Na2WO4-2 wt%Mn/SiO2 particle catalyst and the under-layer 3 wt%Ce-5 wt%Na2WO4-2 wt%Mn/SBA-15/Al2O3/FeCrAl metal-based monolithic catalyst as well as a side tube in the interspaces of two layers for supplementing O2. The reaction performance of oxidative coupling of methane (OCM) in the dual-bed reactor system is evaluated. The effects of the reaction parameters such as feed CH4/O2 ratio, reaction temperature and side tube feed O2 flowrate on the catalytic performance are investigated. The results indicate that the suggested mode of dual-bed reactor exhibits an excellent performance for OCM. CH4 conversion of 33.2%, C2H4 selectivity of 46.5% and C2 yield of 22.5% could be obtained, which have been increased by 6.4%, 4.1% and 5.5%, respectively, as compared with 5 wt%Na2WO4-2 wt%Mn/SiO2 particle catalyst in a single-bed reactor and increased by 10.7%, 31.9% and 17.7%, respectively, as compared with 3 wt%Ce-5 wt%Na2WO4-2 wt%Mn/SBA-15/Al2O3/FeCrAl metal-based monolithic catalyst in a single-bed reactor. The effective promotion of OCM performance in the reactor would supply a valuable reference for the industrialization of OCM process.

A series of Ni/SBA-15 catalysts with Ni contents from 5 wt%-20 wt% and CaO-12.5%Ni/SBA-15 catalysts with CaO contents from 1.4 wt%-9.8 wt% have been prepared. The structure of the catalysts was characterized using X-ray diffraction (XRD), N2 adsorption-desorption, transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). The performance of catalytic steam reforming of the poplar leaves to the hydrogen-rich syngas was tested in a fixed-bed reactor. The results indicate that the 7.0wt%CaO-12.5wt%Ni/SBA-15 catalyst exhibits the best performance for the catalytic steam reforming of poplar leaves to hydrogen-rich syngas. The ratio of H2:CO can reach ca 5:1 in the hydrogen-rich syngas. The yield of H2 can reach 273.30 mL/g (poplar leaves). In the CaO-Ni/SBA-15 catalyst, Ni active component mainly fills the role of catalytic steam reforming of the poplar leaves, and CaO active component mainly plays the role as water-gas shift and CO2 sorbent.

A series of Ni/SBA-15 catalysts with Ni contents from 7.5 wt% to 15 wt% were prepared by impregnation method. The effect of O2 and H2O on the combined reforming of the simulated biogas to syngas was investigated in a continuous flow fixed-bed micro-reactor. The stability of the catalyst was tested at 800 °C. The results indicated that 10wt%Ni/SBA-15 catalyst exhibited the highest catalytic activities for the combined reforming of the simulated biogas to syngas. Under the reaction conditions of the feed gas molar ratios CH4/CO2/O2/H2O = 2/1/0.6/0.6, GHSV = 24000 ml·gcat−1·h−1 and the reaction temperature T = 800 °C, the conversions of CH4 and CO2 were 92.8% and 76.3%, respectively, and the yields of CO and H2 were 99.0% and 82.0%, respectively. The catalytic activities of the catalyst did not decrease obviously after 100 h reaction time on stream.

A three-dimensional geometric model of the oxidative coupling of methane (OCM) packed-bed reactor loaded with Na2WO4-Mn/SiO2 particulate catalyst was set up, and an improved Stansch kinetic model was established to calculate the OCM reactions using the computational fluid dynamics method and Fluent software. The simulation conditions were completely the same with the experimental conditions that the volume velocity of the reactant was 80 mL/min under standard state, the ratio of CH4/O2 was 3, the temperature and pressure were 800 °C and 1 atm, respectively. The contour of the characteristics parameters in the catalyst bed was analyzed, such as the species mass fractions, temperature, the heat flux on side wall surface, pressure, fluid density and velocity. The results showed that the calculated values matched well with the experimental values on the conversion of CH4 and the selectivity to products (C2H6, C2H4, CO2, CO) in the reactor outlet with an error range of ±2%. The mass fractions of CH4 and O2 decreased from 0.6 and 0.4 in the catalyst bed inlet to 0.436 and 0.142 in the outlet, where the mass fractions of C2H6, C2H4, CO and CO2 were 0.035, 0.061, 0.032 and 0.106, respectively. Due to the existence of laminar boundary layer, the contours of each component bent upwards in the vicinity of the boundary layer. This OCM reaction was volume increase reaction and the total moles of products were greater than those of reactants. The flow field in the catalyst bed maintained constant temperature and pressure. The fluid density decreased gradually from 2.28 kg/m3 in the inlet of the catalyst bed to 2.22 kg/m3 in the outlet of the catalyst bed, while the velocity increased from 0.108 m/s to 0.115 m/s.A three-dimensional geometric model of OCM packed-bed reactor was set up and the contour of the characteristics parameters in the catalyst bed was calculated using the computational fluid dynamics method and Fluent software.Download full-size image

A series of Ni/SBA-15 catalysts with 5wt% to 15wt% Ni content as well as a series of 12.5%Ni/Cu/SBA-15 catalysts with 1% to 10% copper content were prepared by the impregnation method. The catalytic performance for partial oxidation of methane was investigated in a continuous flow microreactor under atmospheric pressure. The textural and chemical properties of the catalysts were characterized by XRD, TEM, BET and H2-TPR techniques. The results indicated that the catalysts modified with Cu promoter showed better performance than those without modification. For the 12.5%Ni/2.5%/Cu/SBA-15 catalyst, at 850 °C the conversion of CH4 reached 97.9% and the selectivity of CO and H2 reached 98.0% and 96.0%, respectively. In XRD patterns of the Ni/Cu/SBA-15 catalyst with 7.5 to 10% Cu contents there were CuO characteristic peaks beside NiO characteristic peaks. The mesoporous structure of SBA-15 was retained in all of the catalysts. TPR analysis of the catalysts revealed that a strong interaction between Ni, Cu promoter and SBA-15 support may be existed. This interaction enhanced significantly the redox properties of the catalysts resulting in the higher catalytic activity.

A series of B-Ni2P/SBA-15/cord monolithic catalysts were prepared by coating the slurry of the B-Ni2P/SBA-15 precursors on a pretreated cordierite support, and followed by temperature-programmed reduction in a H2 flow. The samples were characterized by X-ray diffraction (XRD) and N2 adsorption–desorption technique. The catalytic activities for the hydrodesulfurization (HDS) of dibenzothiophene (DBT) were evaluated. The results showed that Ni2P phase was present in all B-Ni2P/SBA-15/cord monolithic catalysts. The specific surface areas (SBET) of the B-Ni2P/SBA-15/cord monolithic catalysts was first increased to 167 m2·g− 1, and then decreased to 155 m2·g− 1 with the increase of boron contents. The catalytic activity also showed the similar trend with the increase of boron contents. The 1.75% (by mass) B-Ni2P/SBA-15/cord monolithic catalysts exhibited the highest DBT conversion of 98.4% at 380 °C. The cordierite-based monolithic catalysts showed better low temperature sensitivity for HDS of DBT in comparison with the particle catalysts. Moreover, two HDS routes, direct desulfurization (DDS) and hydrogenation (HYD), proceeded independently over B-Ni2P/SBA-15/cord monolithic catalysts and the main pathway was DDS.A series of B-Ni2P/SBA-15/cord monolithic catalysts with different B contents were prepared by coating the slurry of the B-Ni2P/SBA-15 precursors on a pretreated cordierite support, and followed by temperature-programmed reduction in a H2 flow. The structure of monolithic catalysts was characterized and the catalytic activities for the hydrodesulfurization (HDS) of dibenzothiophene (DBT) were evaluated. The cordierite-based monolithic catalysts exhibited the better catalytic activities and low temperature sensitivity for HDS of DBT. Two HDS routes, direct desulfurization (DDS) and hydrogenation (HYD), proceeded independently in the cordierite-based monolithic catalysts and the main pathway was DDS.Download full-size image

The TiO2/SiO2@Fe3O4 photocatalysts were synthesized via two steps. First, the SiO2@Fe3O4 particles were synthesized using Fe3O4 as the core and tetraethoxysilane (TEOS) as silica source. Second, the anatase TiO2 was coated on the SiO2@Fe3O4 particle surface using tetrabutyl titanate (TBOT) as titanium source. The synthesized samples were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), N2 adsorption–desorption techniques and vibration sample magnetometer (VSM). The catalytic activity of TiO2/SiO2@Fe3O4 catalysts for the photocatalytic degradation of Rhodamine (RhB) was evaluated under ultraviolet (UV) irradiation. The results indicated that the mean size of the 6%SiO2@Fe3O4 particles was about 75–80 nm and thickness of the homogeneous SiO2 layer was about 2–3 nm. The diameter of 50%TiO2/6%SiO2@Fe3O4 microspheres was about 100 nm and thickness of the homogeneous anatase TiO2 layer was about 8–10 nm. The saturation magnetization and specific surface area of 50%TiO2/6%SiO2@Fe3O4 catalysts were 48.6 emu/g and 495.3 m2/g, respectively. The 50%TiO2/6%SiO2@Fe3O4 microspheres exhibited the best photocatalytic performance. The conversion of RhB achieved up to 98.1% after 60 min UV irradiation, and the photocatalytic reaction apparent rate constant ka was 0.05288 min−1. After used for 8 times, it also maintained high degradation rate and catalyst recovery.Graphical abstractThe core-shell TiO2/SiO2@Fe3O4 magnetic microspheres photocatalysts were synthesized by a simple sol–gel method. The magnetic microspheres possessed the higher BET surface area and the stronger superparamagnetism. The photocatalysts have an excellent photocatalytic performance for the photocatalytic oxidation degradation of Rhodamine and reusability.Download high-res image (177KB)Download full-size imageHighlights► Core-shell TiO2/SiO2@Fe3O4 magnetic microspheres photocatalysts were synthesized by a simple sol–gel method. ► The TiO2/SiO2@Fe3O4 possessed the high BET surface area up to 495.3 m2 g−1 and the strong superparamagnetism up to 48.6 emu/g. ► The TiO2/SiO2@Fe3O4 photocatalysts showed the excellent photocatalytic performance for the photocatalytic oxidation degradation of Rhodamine and the reusability.

Some novel half titanocene catalysts containing phosphodiesterase isooctyl (p204) were synthesized and their catalytic performances for the copolymerization of ethylene-propylene were investigated. The results showed that the half titanocene catalysts had a good catalytic activity in the copolymerization of ethylene-propylene. The catalytic properties of the catalysts were effected by the ligand p204, the mass of propylene in gas reactants, the reaction temperature and the pressure of copolymerization reaction, and the ratio of methylaluminoxane (MAO)/Ti.

A series of Ni/SBA-15/Al2O3/FeCrAl metal monolith catalysts with different Ni contents (5 wt%, 10 wt% and 15 wt%) as well as 10% Ni/CexZr1−xO2/SBA-15/Al2O3/FeCrAl (x = 0, 0.5 and 1) metal monolith catalysts with CexZr1−xO2 of 1.7 wt% were prepared and characterized by X-ray diffraction (XRD) and temperature-programmed reduction (TPR). The catalytic activity and stability of these catalysts for steam reforming of methane (SRM) were evaluated in a continuous flow microreactor. The results showed that Ni/SBA-15/Al2O3/FeCrAl metal monolith catalysts with Ni loading above 10 wt% had good catalytic activities under atmospheric pressure. For 10% Ni/CexZr1−xO2/SBA-15/Al2O3/FeCrAl (x = 0, 0.5 and 1) metal monolith catalysts, CeO2 and Ce0.5Zr0.5O2 as promoters can improve the activity and stability of metal monolith catalysts, while the addition of ZrO2 can lead to the decrease of catalytic activity and stability. The 10% Ni/Ce0.5Zr0.5O2/SBA-15/Al2O3/FeCrAl metal monolith catalyst exhibited excellent activity and stability at 800 °C for 110 h on stream. The activity of 10% Ni/SBA-15/Al2O3/FeCrAl metal monolith catalyst gradually decreased at 800 °C after 60 h on stream. The reason for this phenomenon is probably the formation of NiAl2O4 on the surface of catalyst.

A series of Pd/SBA-15 and Pd/5% Ce1−xZrxO2/SBA-15 (x=0–1) catalysts with Pd content ranging from 0.05% to 1% were prepared. The activity and stability of the catalysts for the combustion of methane were evaluated. The catalysts were characterized by X-ray diffraction (XRD), N2 adsorption–desorption, CO chemisorption, transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and temperature-programmed reduction (TPR). Deactivation behavior of the catalysts for the catalytic combustion of methane was investigated. The results show that all of the catalysts retained the SBA-15 mesoporous structure, with PdO and Ce1−xZrxO2 being confined in the channels. It is proposed that deactivation of the catalysts is associated with accumulation of Pd0, which cannot be efficiently reoxidized to PdO or PdO2, due to the limited oxygen-transfer ability of the catalysts. The incorporation of the ZrO2 as a promoter leads to an increase in the oxygen storage capacity and oxygen mobility of the catalysts, which in turn increases the rate of oxidation of Pd0 and mitigates deactivation of the catalyst.

An LaFe0.5Mg0.5O3/Al2O3/FeCrAl metallic monolith catalyst for the exothermic catalytic combustion of methane and an Ni/SBA-15/Al2O3/FeCrAl metallic monolith catalyst for the endothermic reforming of methane with CO2 have been prepared. A laboratory-scale tubular jacket reactor with the Ni/SBA-15/Al2O3/FeCrAl catalyst packed into its outer jacket and the LaFe0.5Mg0.5O3/Al2O3/FeCrAl catalyst packed into its inner tube was devised and constructed. The reactor allows a coupling of the exothermic and endothermic reactions by virtue of their thermal matching. An experimental study in which the temperature difference between the chamber of the external electric furnace and the metallic monolith catalyst bed in the jacket was kept very small, by adjusting the power supply to the furnace, confirmed that the heat absorbed in the reforming reaction does indeed partly come from that evolved in the catalytic combustion of methane, and that the direct thermal coupling of the two reactions in the reactor can be realized in practice. When the temperature of the electric furnace chamber was 1088 K, and the gas hourly space velocities (GHSVs) of the reactant mixtures passed through the inner tube and the jacket were 382 h−1 and 40 h−1, respectively, the conversions of methane and CO2 in the reforming reaction were 93.6% and 91.7%, respectively, and the heat efficiency reached 81.9%. Stability tests showed that neither catalyst underwent deactivation during 150 h on stream.