Hollow zeolite microspheres have attracted considerable interest due to their unique properties and great potential applications. In this work, we report a simple and cost-effective approach for constructing hollow zeolite microspheres based on a biomass-derived template, i.e., carboxymethylcellulose sodium (CMC). As an example, a hollow ZSM-5 microsphere with a hollow core smaller than 1 μm in diameter and a complete crystal shell is synthesized. This approach overcomes most of the limitations associated with the existing methods, such as complex operations and costly spherical templates. By studying the growth process in detail, a possible formation mechanism is proposed. The crystallization of the hollow zeolite microsphere is through a “surface to core” process, in which the interaction between the CMC and the zeolite gel and the decomposition of the polymer network play the critical roles.

UiO-66 was successfully synthesized in the absence of any amide solvents and hydrochloric acid by using the dry-gel conversion (DGC) method for the first time. The prepared UiO-66 samples (denoted as UiO-66-DGC) were characterized by XRD, SEM, TGA, CO2 adsorption, NH3-TPD, and N2 adsorption. The results showed that the UiO-66-DGC-E sample synthesized by using ethanol as solvent has similar crystallinity and morphology to the UiO-66 sample prepared by the conventional solvothermal method (denoted as UiO-66-S). However, it has more linker deficiencies, indicating the presence of more defects exposed in Zr clusters. As a result, the prepared UiO-66-DGC-E sample exhibited high catalytic activity and reusability in esterification. This preparation method provides a new alternative method for the efficient and eco-friendly synthesis of metal–organic frameworks (MOFs) and modification of their properties.

•Mesoporous Mg-Al composite oxides with excellent structural and surface properties.•A highly homogeneous incorporation of Mg into the mesoporous framework of alumina.•A superior structural stability up to 1000 °C coupled with a large surface area.•A salt effect from the addition of Mg(NO3)2·6H2O to explain the formation mechanism.Highly ordered mesoporous magnesium-aluminium composite oxides (denoted as OMMA-x) with a variety of nAl/nMg ratios have been successfully synthesized via a facile strategy, and a salt effect was proposed to explain the formation mechanism. The incorporation of Mg can significantly improve the structural and surface properties of ordered mesoporous alumina (OMA) material. The resultant OMMA-x exhibited a much more ordered 2-D hexagonal mesostructure, a narrower pore size distribution, a higher specific surface area and pore volume, and a stronger basicity than those of OMA. More importantly, the highly homogeneous incorporation of Mg at the atomic level and the formation of framework MgOAl bonds could effectively suppress the formation of crystalline alumina during the calcination process. As a result, OMMA-x demonstrated a superior thermal stability. For example, the ordered mesostructure of OMMA-8 could be well maintained with a high surface area of 182 m2/g even after thermal treatment at 1000 °C.A schematic procedure to illustrate the preparation of highly ordered mesoporous Mg-Al composite oxides (OMMA-x) with highly homogeneously dispersed Mg species and enhanced structural stability.

A general and robust protocol for the synthesis of terminal α-substituted vinylphosphonates via Suzuki coupling of α-bromovinylphosphonates with organotrifluoroborates has been successfully developed. This method features a broad substrate scope, great functional group compatibilities, and easy scale-up ability. In addition to easy access of nucleophiles, a straightforward synthesis of electrophiles was also realized with diethyl α-bromoethenylphosphonate as the starting material. With a combination of Pd2(dba)3/SPhos as the catalyst, a range of α-alkyl, aryl, heteroaryl, and alkynyl substituted ethenylphosphonates could be nicely accessed under mild conditions. As a synthetic application, the terminal vinylphosphonate was utilized as an effective Michael acceptor in the visible-light-promoted Giese reaction.

Systematic periodic density functional theory computations including dispersion correction (GGA-PBE-D3) have been carried out to characterize the location, distribution and acidity of Al substitution in ZSM-5 with different Si/Al ratios (up to 8 Al atoms). The model system is the orthorhombic phase, which has a unit cell containing 96 T sites. For one Al substitution, there are two energetically equal sites (T3 and T7) as the most stable substitution configurations. On the basis of the computed relative stability of the NH3 adsorbed states, there are three and two energetically close states at the T7 and T3 sites, respectively, indicating the equilibrium and mobility of the chemisorbed NH3 (or NH4+) among these states. For 2Al substitution, the most stable substitution configuration has Al atoms at the T3 and T11 sites, and the two most stable acidic O–H groups have the same NH3 adsorption energies. For 3Al and 4Al substitutions, not all generated O–H acidic sites are available for NH3 adsorption due to the confinement effect, and higher Al substitutions might not have advantages over lower Al substitutions for ZSM-5. Among the most stable substitution configurations for 1–4 Al substitutions, the T3 site appears most frequently and should represent the active site for adsorption and reaction.

A double-chain quaternary ammonium salt of dioctyl dimethyl ammonium chloride (DDAC8) was first used as a low-cost template to prepare the mesostructured zirconia nanomaterials in an alcohol-thermal system. The material was calcinated to obtain pure tetragonal crystalline zirconia (t-zirconia) and thus has significantly improved original structure properties, including a narrow pore size distribution of 4–7 nm and a high surface area of 195 m2/g. The t-zirconia hierarchical nanoparticle aggregate material is different from the smooth microsphere material obtained using the single chain quaternary ammonium salt template. The characteristic rough surface morphology results from the grid distribution form of the DDAC8 micelles in the ethanol solution and caused the formation of more defect sites, which demonstrate the potential for possible catalytic applications. A formation mechanism of the mesoporous zirconia nanomaterial in the alcohol-thermal system of the surfactants is reasonably explained. The synthesis system may provide a new approach to the preparation of mesoporous nanomaterials.

•α-Substituted ethylphosphonates were efficiently accessible based on CuH catalysis.•Phosphono substituted alkene could be reduced in a highly selective manner.•The competitive reduction of vinylphosphonate and acrylate was investigated.An unprecedented approach toward synthesis of α-substituted ethylphosphonates based on CuH-catalyzed conjugate reduction of vinylphosphonates has been successfully developed. This protocol features mild conditions, broad substrate scope, good functional group compatibility, high overall efficiencies, and easy gram-scale synthesis. The Cu-catalyzed reduction takes place in a highly selective manner on the phosphono substituted CC bond in the case of the reaction of alkenylphosphonates bearing both phosphono and alkyl or aryl substituted alkene moieties. Furthermore, the result of competitive reaction indicates that the Cu-catalyzed conjugate reduction of vinylphosphonate is more challenging and reproducible than the corresponding acrylate’s reaction.Download high-res image (82KB)Download full-size image

The sulfated zirconia was prepared by directly impregnating ammonium persulphate on the crystalline zirconia and followed by the calcination temperatures of 300–500°C. The structural properties of the catalysts were characterized by X-ray diffraction (XRD), N2 adsorption-desorption, ammonia temperature programmed desorption (NH3-TPD), Fourier transform infrared spectroscopy (FT-IR) and a scanning electron microscope (SEM) equipped with an energy dispersive spectroscope (EDS). The experiment results demonstrated that the catalysts presented the tetragonal structure of zirconia and high crystallinity. The catalyst calcined at 500°C possessed the highest sulfur content and acidic sites in the catalysts. The catalyst exhibited high catalytic activity in transesterification of soybean oil with methanol. The yield of biodiesel achieved 84.6% because of the preferable super-acid sites on the surface of the catalyst.

•Zeolite composite is composed by Y zeolite and single-crystal-like ZSM-5.•A composite material formed by a process like “big fish swallowing little one”.•Ratio of two zeolites in the as-synthesized sample can be adjusted.Zeolite-zeolite composite composed of Y and ZSM-5 zeolite was prepared using depolymerized Y as partial nutrients for the growth of ZSM-5. The as-synthesized samples were characterized by X-ray powder diffraction (XRD), FT-IR, scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), transmission electron microscopy (TEM), N2 adsorption-desorption measurement and Thermogravimetric analysis (TG). Chemical equilibrium at the solution-crystal interface was changed because of the partially depolymerized Y zeolite, the conditions necessary for the growth of ZSM-5 were therefore obtained. ZSM-5 zeolite crystals nucleated and grew on the interface, and Y zeolite crystals were then gradually swallowed by the growing single-crystal-like ZSM-5.Y zeolite crystals in the hydrothermal system were partially depolymerized and an ambience in favor of the formation of ZSM-5 was formed, and ZSM-5 zeolite crystals nucleated and grew up on the external surfaces of Y zeolite crystals. As a consequence, Y zeolite crystals were swallowed by single-crystal-like ZSM-5.Download high-res image (196KB)Download full-size image

•The S2O82 −/ZrO2 material is synthesized by one-pot method using ammonium persulfate.•The material with stabile S2O82 − component has extraordinarily abundant superacid.•The material has high activity and selectivity for producing biofuel even at 100 °C.•The favorable catalysis results from t-ZrO2 microcrystallites anchored more S2O82 −.•No sulfur leaching in cyclic utilization of the catalyst for the reaction.A solid super acid catalyst, S2O82 −/ZrO2, was prepared by a new synthesis route of one-pot method with ammonium persulfate via vapor phase hydrolysis to improve biodiesel production using expired soybean oil as reactant. Catalysts were characterized by X-ray diffraction (XRD), transmission electron microscope (TEM), and NH3-temperature programmed desorption (NH3-TPD) to determine the optimum pretreatment conditions and understand the role of the active sites for transesterification. S2O82 −/ZrO2 calcined at 500 °C, which showed an amorphous phase by XRD characterization, was identified as composed of tetragonal phase ZrO2 microcrystallites by TEM examination. The microcrystallites which anchored more S2O82 − had abundant super acid and displayed high catalytic activity in the transesterification under mild reaction conditions. The reaction parameters over the catalyst were optimized and both the conversion of soybean oil and selectivity of biofuel reached 100% under the conditions of 110 °C of reaction temperature, 4 h of reaction time and 20:1 of methanol to oil molar ratio. Moreover, the catalyst showed high stability in the reactions and no sulfur leaching was found in the biodiesel products in cyclic utilization.

•Preparation of a series of super-microporous alumina-zirconia materials.•The synthetic strategy is facile and benign without addition of acid or base.•The materials with narrow pore size distribution of 1.5 nm.•The materials with high thermal stability up to 800 °C.A new family of super-microporous zirconia-based alumina-zirconia materials (pore size 1–2 nm) have been synthesized successfully using an eco-friendly template via an evaporation-induced self-assembly (EISA) pathway. Moreover, no extra acid or base is added in our synthesis process. When the atomic ratio of aluminum to zirconium is 1, the as-obtained sample exhibits a surface area of 400 m2/g when calcined at 400 °C and can maintain a microporous structure with a high surface area of 216 m2/g even when treated at 800 °C, demonstrating its high thermal stability. The material has functionally support effects in the methanation of syngas.

A general and simple protocol for the synthesis of α-substituted alkenylsulfones has been developed firstly via palladium-catalyzed Suzuki reactions between α-bromo ethenylsulfones and organoborons. Using a catalyst composed of Pd(OAc)2 and SPhos, a variety of aryl, heteroaryl, and alkylboron reagents could efficiently couple with α-bromo ethenylsulfones under mild conditions. Moreover, it has been demonstrated for the first time that vinyl sulfones underwent smooth reduction by diimide generated from 2-nitrobenzenesulfonylhydrazide.

•A series of super-microporous basic magnesia-zirconia microcrystalline materials.•The facile and benign synthetic method without addition of acid or base and humidity condition.•The materials with narrow pore size distribution of 1.5 nm.•The efficient materials in the soybean oil transesterification.The super-microporous microcrystalline MgO-ZrO2 nanomaterials (pore size 1–2 nm) was prepared successfully via a facile one-pot evaporation-induced self-assembly (EISA) method and employed in the transesterification of soybean oil and methanol. X-ray diffraction, transmission electron microscope, temperature programmed desorption of CO2, and N2 adsorption porosimetry were employed to characterize the nanocomposites. Nitrogen sorption isotherms revealed that these materials had large surface areas of more than 200 m2/g. Moreover, the sample with a Mg/Zr molar ratio of 0.5 and calcined at 400 °C showed high biodiesel yield (around 99% at 150 °C).Download high-res image (107KB)Download full-size image

In order to understand the effects of the surface acid sites in mesoporous zeolites on the adsorption and diffusion of hydrocarbons, the adsorption and diffusion of n-heptane and toluene (two C7 hydrocarbons) over the mesoporous HZSM-5 zeolites (SiO2/Al2O3 = 36) were investigated. The adsorption isotherms of two C7 hydrocarbons over the mesoporous HZSM-5 zeolites showed the experimental data good fitting to dual-site Langmuir-Freundlich model (DSLF) similar to mesoporous NaZSM-5. Henry's constants and the initial heats of adsorption displayed stronger interactions in HZSM-5 than in NaZSM-5, especially for n-heptane, due to the presence of surface acid sites. The influence of acidity to the adsorbate-adsorbent interactions decreases with increasing of the mesoporosity. The investigation on the diffusion of n-heptane and toluene in mesoporous HZSM-5 samples by the zero-length column (ZLC) method showed the strong interaction of adsorbates and HZSM-5 samples by effective diffusivity and activation energy. Moreover, the diffusions of adsorbates in zeolites were advanced with the introduction of mesopores in the zeolitic samples, though the dramatic influence of mesopore to diffusion is not arisen in mesoporous NaZSM-5, reflecting larger influence of acid sites on diffusion in mesoporous HZSM-5 samples.

•Nanoporous zirconia materials with controlled pore structures.•Eco-friendly synthesis method for the materials without addition of acid or base.•The average pore diameters range from 1.2 to 4.2 nm.Microporous/mesoporous zirconia materials have been successfully synthesized by controlling hydrolysis rate without adding acid or base and calcining under mild conditions, and characterized by XRD, TEM and N2 adsorption-desorption. The results show that the as-synthesized materials are super-microporous (pore size in the range of 1–2 nm) as using dimethyl distearyl ammonium chloride as the template, but mesoporous (pore size >2 nm) when didodecyl dimethyl ammonium chloride and bisoctyl dimethyl ammonium chloride are employed. By changing the carbon chain length of the templates, the average pore sizes of the zirconia samples are tailored, and a range of pore sizes from 1.2 to 4.2 nm is obtained.

A simple and straightforward method for the synthesis of α-substituted ethylphosphonates via diimide reduction strategy is described. With K3PO4 or Na2CO3 as the basic additive, a range of terminal alkenylphosphonates underwent efficient reduction by diimide generated from 2-nitrobenzenesulfonylhydrazide (NBSH) under room temperature. The high functional group tolerance of this methodology is also demonstrated. Moreover, our method features high safety, mild reaction condition, low requirement on equipment, and high chemoselectivity.

The SBA-16 obtained by different routes of elimination of organic templates were used as the hosts for encapsulation of chiral Ru complex (1S,2S)-DPEN-RuCl2(TPP)2 (1) (DPEN = 1,2-diphenylethylene-diamine, TPP = triphenyl phosphine). The methods for removing templates had distinct effects on the amount of residual template in SBA-16, which made the SBA-16 with different surface and structure properties. 1 encapsulated in SBA-16 extracted with the mixture of pyridine and ethanol showed higher activity and enantioselectivity for acetophenone asymmetric hydrogenation.

A hierarchical ZSM-5 zeolite composed of nano-sized MFI zeolite crystals was synthesized without using secondary template by a traditional hydrothermal procedure. The as-synthesized hierarchical ZSM-5 and a reference catalyst were both characterized by XRD, SEM, FT-IR, in situ infrared (IR) spectrometry of pyridine, NH3-TPD, N2 adsorption–desorption, intelligent gravimetric analyzer, and by thermogravimetry analyses. After examining and comparing the results, it is discovered that the hierarchical ZSM-5 catalyst displays excellent catalytic performance with an improved conversion of isopropylbenzene and a longer catalytic life because of its dramatically enlarged external surfaces. The results also display that the shortened diffusion path length contributes to enhancing the stability of the hierarchical catalyst by depressing the coking deposit during the catalytic cracking of n-octane.

It has been demonstrated for the first time that α-phosphonovinyl tosylates could efficiently couple with a range of arylboronic acids to access α-arylethenylphosphonates. The unprecedented procedure exhibits excellent functional group tolerance, giving the terminal vinylphosphonates in good to excellent isolated yields (60–99%) under mild reaction conditions.

Nickel and cobalt salen complexes were simultaneously encapsulated in mesoporous zeolite A by flexible ligand method. The prepared catalyst NiCosalenA was investigated for its electrochemical behavior and electrocatalytic activity towards the oxidation of methanol on glassy carbon electrode in 0.1 M NaOH solution. Upon encapsulation in zeolite A, the NiCosalen complex exhibits the typical cyclic voltammetric response, which can be anticipated for the Ni2+Co2+(Salen)(OH)2/Ni3+Co3+(Salen)O(OH) redox couple. It also showed much higher electrocatalytic activity towards the oxidation of methanol than pure NisalenA, due to a synergetic effect that may originate from the interaction of Ni(salen) and Co(salen) and/or the formation of dinuclear salen complexes in adjacent or appropriate sites in a nano-cage through the lattice oxygen of the zeolitic host. The mechanism of electrocatalytic oxidation of methanol on NiCosalenA modified electrode was proposed to be EC process. In both the chronoamperometric and chronocoulometric studies, the reaction of methanol electrooxidation followed a Cottrellian behavior and similar diffusion coefficients (D) of methanol were found to be 3.82 × 10−7 cm2 s−1 and 3.91 × 10−7 cm2 s−1, respectively. The catalytic rate constant (kcat) was also calculated to be 5.52 × 105 cm3 mol−1 s−1 in the range of 0.005–2.0 M of methanol.

Controlled synthesis of porous metal oxides with desired morphology has been motivating scientists to explore and develop new preparation methodologies. Among them, thermal decomposition of metal–organic frameworks (MOFs) has been employed for the fabrication of several metal oxides. In this work, this strategy is employed to prepare mesoporous and tetragonal zirconia (t-ZrO2) from a metal–organic framework (UiO-66), acting as both a morphological template and a zirconium source. This process avoids the use and removal of an extra template as well as the addition of stabilizers for t-ZrO2. After thermal decomposition at 500 °C, t-ZrO2 inherited an octahedral morphology from the pristine precursor and possessed small nanoparticles with an average size of 3.1 nm. The derived t-ZrO2 had a large surface area of 174 m2 g−1 and a pore diameter of 5–8 nm. The formation mechanism of t-ZrO2 was also discussed. This simple and potentially universal strategy can be used to fabricate porous metal oxides with desired shape for many applications.

•Two kinds of metal salen complexes are simultaneously encapsulated in zeolite.•NiMnsalenA shows superior electrocatalytic activity for methanol oxidation.•Electrooxidation ability of bimetal-complexes in zeolite is higher than single one.•The rate-determining step for methanol oxidation vary with the potential.•Oxidation of methanol and desorption of intermediates are key factors in oxidation.Nickel and manganese salen complexes were simultaneously encapsulated in the supercages of the mesoporous zeolite A by using the flexible ligand method. The electrochemical behavior and electrocatalytic activity toward the electrooxidation of methanol on glassy carbon electrode coated with NiMnsalenA (NiMnsalenA/GCE) in 0.1 M NaOH solution were studied by cyclic voltammetry (CV), chronoamperometry (CA) and AC electrochemical impedance spectroscopy (EIS). The results showed that the addition of small amounts of Mn species can give rise to much higher electrocatalytic activity than the pure NisalenA toward the oxidation of methanol, mainly due to a synergetic effect that may originate from the interaction of Ni(salen) and Mn(salen) and/or the formation of dinuclear salen complexes via the lattice oxygen of the zeolitic host. Kinetic parameters such as the electron transfer coefficient α, the rate constant ks of the electrode reaction and the charge transfer coefficient of the catalytic reaction, αn were determined to be 0.40, 1.898 s−1 and 0.43, respectively, and the detection limit was found to be 97.66 μM. The mechanism of electrocatalytic oxidation of methanol on NiMnsalenA/GCE was investigated and proposed to be done by reaction with Ni3+(salen)O(OH) and also direct electro-oxidation reaction. The impedance behaviors showed different patterns at different applied potentials, indicating the changes of the rate-determining step, from the methanol electrooxidation leading to the formation of intermediates on the surface of electrode gradually to the oxidation and removal of adsorbed intermediates. The influence of methanol concentration on the impedance behaviors was also studied and the results demonstrated that the semidiameters of the Nyquist diagrams decreased with the increase of methanol concentration, signifying the acceleration of the reaction rate of methanol electrooxidation.

•Hierarchical zeolite composite fabricated by using ZSM-5 as nutrients for the growth of SAPO-34.•Incompatibility of core and shell was circumvented by using core as nutrients for the growth of shell.•Depolymerization of core contributes to the transmission of Si-species from cores to shell layers.•The tunable ZSM-5/SAPO-34 ratios offered the zeolite composite the adjustable acidity properties.•Large mesopore volumes and mesopore areas were obtained with slightly sacrificed microporosity.A series of zeolite composites with a hierarchical pore system were prepared by using ZSM-5 zeolite powder as the nutrients for the growth of SAPO-34. Factors controlling the formation of the aimed zeolite composite were investigated in details. The structural, crystalline, and textural properties of the zeolite composites, as well as the references ZSM-5, SAPO-34 and physical mixture composed of ZSM-5 and SAPO-34, were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) analyses, intrusive mercury experiments, Fourier transform infrared spectroscopy (FTIR), temperature-programmed desorption of ammonia (NH3-TPD), and nitrogen adsorption/desorption techniques. The results display that the incompatibility of the core and shell layer with the different zeolite structure types, chemical compositions and crystallization conditions can be circumvented by using ZSM-5 zeolite cores as the nutrients for the growth of SAPO-34 zeolite in the shell; acidity properties and the ratios of SAPO-34/ZSM-5 in the composites can be adjusted; a hierarchical system with a mesopore centering at about 15 nm and a macropore centering at about 150 nm was introduced into the zeolite composite samples.

A series of highly ordered mesoporous cobalt–alumina catalysts (denoted as OMCA-x) with a variety of nAl/nCo ratios have been successfully synthesized via an evaporation-induced triconstituent cooperative co-assembly method and were applied to the liquid phase selective oxidation of styrene using difficult-to-activate molecular oxygen as the oxidant at atmospheric pressure. For comparison, a cobalt catalyst with a nAl/nCo ratio of 10 supported on ordered mesoporous alumina (denoted as Co/OMA-10) was also prepared by a traditional incipient wetness impregnation (IWI) method. Although both kinds of catalysts retained a unidimensionally ordered mesoporous structure, the textural and catalytic properties of the catalysts were significantly affected by the preparation methods. The characterisation and catalytic results confirmed that the OMCA-x catalysts exhibited a much more highly ordered hexagonal mesostructure, a narrower pore-size distribution, a higher Brunauer–Emmett–Teller surface area and pore volume, and higher catalytic activity and selectivity towards styrene oxide than those of Co/OMA-10. The improved catalytic activity of the OMCA-x catalysts can be attributed to the highly homogeneous dispersion of the Co species within the mesoporous alumina framework in the form of tetrahedrally coordinated divalent Co-oxide moieties, which can efficiently activate molecular oxygen into peroxo and superoxo radical-type active oxygen species. In addition, the incorporation of Co into the mesoporous framework of alumina and the formation of Co–O–Al bonds can effectively increase the content of tetra- and penta-coordinated framework aluminum, and further facilitate the formation of tetrahedrally coordinated Ia type Al–OH species as catalytic centers for styrene epoxidation, which is advantageous in improving the selectivity towards styrene oxide.

•The nanocrystalline alumina with high BET surface area and extremely high thermal stability.•The super-microporous alumina transforming to mesoporous by varying the mixed templates.•A facile synthetic route for alumina with controlled pore structures.We report a facile synthesis of porous alumina (PA) which enables control of pore structure using a mixture of fatty alcohol polyoxyethylene ether (AEO-7) and poly (alkylene oxide) triblock copolymers (P123) as the template via an evaporation-induced self-assembly (EISA) pathway associated with thermal treatment. N2 adsorption–desorption results show that using over 80 wt% AEO-7, the obtained materials are super-microporous (pore size in the range of 1–2 nm), then if further decrease in the AEO-7 content will transform to mesopore (pore size >2 nm). When the mass fraction of P123 is less than 20 wt%, the material has a large surface area (more than 650 m2/g) and nanocrystalline phase is obtained at 400 °C. Even after calcination at 750 °C for 1 h, the sample of mass fraction 20 wt% P123 still exhibits a high specific area of 450 m2/g with large microporosity.

•A novel strategy for preparing metal complex functionalized LDH was proposed.•The immobilized metal complexes can be neutral or positive.•The hybrids with high metal complex loading can be prepared by this strategy.In order to immobilize neutral or positive metal complexes on layered double hydroxides (LDHs) and increase the amount of immobilized metal complexes, a novel strategy for the preparation of metal complex functionalized LDHs is proposed. This strategy involves exfoliating glycine-intercalated MgAl LDH in formamide under an ultrasound treatment, and then grafting silylated metal complexes on MgAl LDH nanosheets, as exemplified by immobilization of Co Schiff-base on MgAl LDHs. The prepared hybrids were characterized by XRD, AFM, FT-IR, TG, N2 adsorption–desorption and ICP techniques and their catalytic performances were investigated in H2O2 decomposition and styrene epoxidation with O2. The results showed that the hybrid prepared by this strategy had higher Co Schiff-base loading than the sample prepared by directly grafting silylated Co Schiff-base on glycine-intercalated MgAl LDHs due to the more accessible grafting sites on the exfoliated MgAl LDH nanosheets. Additionally, it was found that the grafted complexes could effectively impede the restack of LDH nanosheets after removal of the solvent. Thus, the prepared hybrid exhibited higher surface area and more accessible active centers, which made the prepared hybrid exhibit high catalytic activity in H2O2 decomposition and styrene epoxidation with O2. This work gives us a new way to prepare LDH hybrids functionalized with various metal complexes.

Nickel and zinc salen complexes were simultaneously encapsulated in the supercages of the mesoporous zeolite A by using the flexible ligand method. This heterogeneous catalyst NiZnsalenA was characterized by X-ray diffraction, infrared spectroscopy, diffuse reflectance UV-vis spectroscopy, elemental analysis, and N2 adsorption/desorption experiments. The techniques of cyclic voltammetry (CV) and chronoamperometry (CA) were employed to investigate the electrochemical behavior and electrocatalytic activity toward the oxidation of methanol on NiZnsalenA glassy carbon electrode (GCE) in 0.1-M NaOH solution. The CV results presented a pair of redox peaks associated with the Ni2+(salen)(OH)2/Ni3+(salen)O(OH) redox couple. NiZnsalenA also showed the superior electrocatalytic activity to the oxidation of methanol than pure Ni-modified electrode, mainly due to a synergetic effect in NiZnsalenA. This synergetic effect may originate from the interaction of Ni(salen) and Zn(salen) and/or the formation of dinuclear salen complexes via the lattice oxygen of the zeolitic host. The effects of the scan rate, methanol concentration, and OH− concentration on methanol oxidation are investigated, and a possible mechanism is proposed that the oxidation of methanol is done by reaction with Ni3+(salen)O(OH) and also direct electrooxidation reaction. The kinetic parameters such as the electron transfer coefficient α and the rate constant ks of the electrode reaction were estimated to be 0.39 and 1.59 s−1, respectively. In both the CA and CC studies, the process of methanol oxidation followed a Cottrellian behavior, and the diffusion coefficients DCA and DCC of methanol represented the similar tendency, where an initial sharp drop was terminated to a very slow change as the concentration of methanol was approaching 0.7 M. The catalytic rate constant kcat increased rapidly until the concentration of methanol was increased above 0.7 M, and then the values of kcat remained almost constant.

A mesoporous beta zeolite was hydrothermally prepared directly by silanizing silica without any mesoporous template via the bond-blocking principle. Si–C bond-blocking arose during the crystalline growth. The crystallization took more than 10 days, but the material had a fairly stable structure and could even be processed up to 32 days later in the hydrothermal system. XRD, N2-adsorption/desorption and TEM/SEM characterization of the materials indicated that the beta zeolite is truly a sponge-like mesoporous zeolite with a BEA topological structure, which consists of self-sustaining macroscopic sized zeolitic aggregates assembled from nanosized crystalline domains of beta zeolite with intracrystalline mesopores. The mesoporous beta zeolite possessed an extremely large external surface area and adjustable mesoporosity. Compared to conventional beta zeolite, FTIR results of pyridine (Py) and 2,6-di-tert-butylpyridine (DTBPy) demonstrated an increase of the Lewis-site contribution and a large improvement for the accessibility of bulky molecules in the mesoporous beta zeolite. Finally the mesoporous beta zeolite exhibited significant activity in the transesterification reaction of triolein to afford methyl oleate (biodiesel) due to the accessibility increase and diffusion-limitation reduction of large lipids to acid sites in the H-beta zeolite framework.

ZSM-5 zeolites with different mesoporosities were prepared by alkaline treatment and characterized by powder XRD and nitrogen adsorption. Two C7 hydrocarbons of n-heptane and toluene were employed as probe molecules to investigate the effects of the introduction of mesopore on the adsorption and diffusion properties of ZSM-5 zeolites by comparing the experimental results of the samples treated and untreated by using NaOH. Adsorption isotherms were measured gravimetrically in the pressure range 0–32 mbar and from 293 to 338 K. The isotherms of microporous and mesoporous ZSM-5 were successfully fitted by using the Langmuir–Freundlich model and the dual-site Langmuir–Freundlich model, respectively. Henry’s constants and the initial heats of adsorption calculated from the adsorption isotherms as well as the fitting parameters displayed that the interactions between adsorbent and adsorbate were weakened after the introduction of mesopore, and the interactions between the adsorbates with microporous surface are much stronger than that between them with the mesoporous surface. Diffusion measurements were undertaken using the zero length column (ZLC) technique at partial pressure of p/p0 < 0.000 15 from 333 to 393 K. The results showed that the effective diffusion constants (Deff/R2) of the two C7 hydrocarbons increased greatly in the presence of mesopores, while the corresponding activation energy decreased due to the reduced diffusion resistance and the shortened diffusion path in the mesoporous zeolites. Also, higher and much more dramatic enhancement of the efficient diffusivities as a function of mesoporous volume for toluene relative to that for n-heptane were found, indicating that the diffusion of n-heptane is controlled by the micropore diffusion and that the diffusion of toluene is exclusively determined by mass transfer through the mesopores.

The growth-controlled zirconia nanocrystals were successfully synthesized via vapor phase hydrolysis without using any capping agents. This method provided the advantage of no high hydrolysis reactivity of precursors. The resultant ZrO2 nanocrystals exhibited the ultrafine nanoscale size of less than 5 nm and a high specific surface area ranging from 400 m2 g−1 to 450 m2 g−1, which could be well controlled by changing the reaction temperature, the reaction time, or the solvent.

•A highly ordered mesoporous alumina with high BET surface area and extremely high thermal stability.•A new synthetic route for preparing ordered mesoporous alumina.•The solvothermal pre-hydrolysis process to obtain more Al-OH species.•The inexpensive and easily available inorganic aluminum nitrate as precursor.By using the inexpensive aluminum nitrate as precursor, a highly ordered mesoporous alumina with high thermal stability has been synthesized successfully via an evaporation-induced self-assembly pathway associated with solvothermal pre-hydrolysis process. The resultant mesoporous alumina maintains the ordered hexagonal mesostructure, narrow pore-size distribution, high BET surface area and large pore volume even after thermal treatment at 900 °C.

•A super-microporous zirconia–alumina material.•The material with high surface area and thermal stability.•The material with narrow pore size distribution of 1.5 nm.•The material was synthesized by an economic template AEO-7.A super-microporous zirconia–alumina (pore size in the range of 1–2 nm) with narrow pore size distribution has been synthesized successfully by using an inexpensive nonionic surfactant fatty alcohol polyoxyethylene ether (AEO-7) as the template in ethanol solvent. As the Zr/Al molar ratio is 0.1, the material has high surface area of 413 m2/g and a large pore volume of 0.17 cm3/g after calcination at 400 °C. Even after calcination at 900 °C, the microporous structure remained, exhibiting a significant thermal stability.

•A granular X-type zeolite/activated carbon composite from elutrilithe.•The composite has a hierarchical porous structure of zeolite and activated carbon.•The high specific surface area, total pore volume, and high mechanical strength.•A new reasonable way for the resource recovery of elutrilithe.The preparation of granular X-type zeolite/activated carbon composites from a locally available elutrilithe by adding pitch powder and solid SiO2 was studied, and the variations in the synthesis process of zeolite X were investigated. The preparation steps of the composite involved (1) calcination of pre-shaped mixture (2) activation of the carbonaceous material from elutrilithe and pitch to prepare activated carbon and (3) hydrothermal conversion (zeolitisation) of aluminosilicate in elutrilithe and additional SiO2 to zeolite X in alkaline medium. The adding of additional SiO2 in the reaction system to adjust SiO2/Al2O3 ratio of the reaction mixture was necessary for the formation of zeolite X. The characterization of XRD, SEM and N2 adsorption of the resulting composites had a hierarchical pore structure, which shows that pure X-type zeolite phase with high crystallinity could be obtained regardless of the content of carbon in the composites.

•Asymmetric chiral Ru(II) complexes were encapsulated in zeolite MY.•The complex encapsulated in LiY has higher ee selectivity than the homogenous.•The alkali metal cation exchanged Y has different host effect to the complex.•The reactivity was supported by DFT calculation and UV–vis spectra ananlysis.Chiral Ru complex, (1S,2S)-DPEN-Ru(TPP)2, has been encapsulated within the supercages of alkali metal cation exchanged zeolite Y by the flexible ligand method. A dramatic blue shift of the charge transfer band observed in the diffuse reflectance UV–vis spectroscopy of the encapsulated Ru complex indicates that chiral Ru complex undergoes distortion upon encapsulation in the zeolite matrix and the distortion degree increases as the size of the alkali metal cation increases. The chiral Ru complexes encapsulated in LiY are found to be more enantioselective than the homogenous and active enantioselective than that in NaY, KY, or CsY in the asymmetric hydrogenation of acetophenone. Density functional theory (DFT) calculation reveals that the exchangeable alkali metal cations greatly influence the interactions of acetophenone/DPEN with zeolite hosts and a weaker interaction between acetophenone/DPEN and LiY is found.

Microspherical MFI mesoporous zeolites (MMZ-5) with different mesopore volumes and similar silica-alumina ratios were prepared by the bond-blocking principle and confirmed by physical methods. The zeolite materials with high external surface areas contained inter- and intra-crystalline mesostructures. NH3-TPD and in situ FT-IR spectra techniques were used to characterize the acidic properties of the mesoporous zeolites. The results showed that the Py-Brönsted acid sites of the MMZ-5 samples are very similar to that of the conventional ZSM-5 zeolite, but the latter Py-Lewis acid sites are greatly larger than the former. Further, the concentration of DMPy-Brönsted acid sites in the mesoporous zeolites arrived at 70 μmol/g, namely, the 2,6-dimethylpyridine (DMPy) molecule can probe 97 % of the Py-Brönsted acid sites in the MMZ-5 zeolites. The introduction of the mesoporous structure into the MMZ-5 zeolites increased strongly the accessibility of the more bulky molecules, such as the DTBPy molecules. As expected, HMMZ-5-2 sample as an acid catalyst displayed a high reaction activity and an uniform product selectivity in the benzylation of p-xylene with benzyl chloride.

A series of MgAl hydrotalcites (HTs) was synthesized in the presence of glucose and used as the precursors for the preparation of MgAl mixed oxides. The as-synthesized MgAl HTs and their corresponding MgAl mixed oxides were characterized by XRD, TG, SEM, N2-adsorption/desorption, FTIR, Raman spectroscopy, ICP and CO2 TPD. The results show that MgAl mixed oxides derived from MgAl HTs prepared in the different synthesis systems have different textural characteristics, basic properties, and catalytic performances. The glucose in MgAl HT synthesis system was transformed into amorphous carbon during the process of MgAl HT crystallization, and the in-situ formed highly dispersed carbon in the as-synthesized MgAl HT matrices can act as a mesoporous template. MgAl mixed oxides derived from MgAl HTs prepared in the presence of glucose have higher surface areas, more uniform mesoporous pores, stronger basic sites as well as higher activities in transesterification of tributyrin with methanol than that from MgAl HT prepared in the absence of glucose.Highlights► A series of hydrotalcites (HTs-x) were synthesized in the presence of glucose. ► The calcined HTs-x showed stronger basic sites than calcined HTs. ► The calcined HTs-x showed uniform mesoporous. ► The calcined HTs-x exhibited high catalytic activity in transesterification.

Composite zeolites composed of MOR and FAU (denoted as MFZ) were synthesized by a two-step hydrothermal crystallization procedure, in which the mixture of pre-synthesized mordenite zeolite acts as the nutrients for the growth of post-synthesized Y zeolite. The structural, crystalline, and textural properties of the as-synthesized materials, as well as the references Y and mordenite zeolite samples, were characterized by XRD, FT-IR, in situ IR spectrometry of pyridine, NH3-TPD, N2 adsorption–desorption and SEM; the composite zeolites and the corresponding physical mixture were investigated during isopropylbenzene catalytic cracking. The results show that the ratio of MOR to FAU in the as-synthesized composite zeolites largely depends on the second-step crystallization time. When the crystallization time is 10–17 h, a composite with different ratio of MOR to FAU can be obtained; as compared with the corresponding physical mixture, the composite sample has a higher isopropylbenzene conversion and a longer catalytic life due to the introduced hierarchical pores system. The catalytic activity of isopropylbenzene cracking over the catalysts has a linear dependence with the revised hierarchy factor (HF′).Graphical abstractHighlights► Hierarchically structured composite zeolites composed of MOR and FAU were prepared. ► Excessive introduction of mesopores into composite zeolites is not beneficial. ► Penalty paid in micropore volume and areas results in a less efficient catalyst.

By using zirconia as promoter, a highly ordered mesoporous alumina with extremely high thermal and hydrothermal stability has been synthesized successfully via an evaporation-induced self-assembly (EISA) pathway associated with thermal treatment. In comparison to pure mesoporous alumina, the resultant mesoporous zirconia–alumina nanomaterials maintain the ordered hexagonal mesostructure, narrow pore-size distribution, high BET surface area and pore volume even after thermal treatment at 1000 °C or boiling water treatment for 6 h. Our contribution provides an important approach to synthesize ordered mesoporous Zr–Al nanomaterials with high thermal and hydrothermal stability, which can find potential application for the catalytic applications in the petroleum industry.Highlights► Highly ordered mesoporous Zr–Al composite nanomaterials. ► Extremely high thermal and hydrothermal stability. ► High zirconium content (Zr/Al atom ratio is 0.2) in the materials. ► New synthesis method to introduce heteroatoms into mesoporous alumina materials.

An ordered mesoporous zeolite LTA is prepared by using organofunctionalized silica as Si-source. The mesoporous zeolite LTA has nano-cages of 3 nm interconnected to each other through 0.8–1.2 nm channels. A Jacobsen salen complex can be encapsulated successfully in the supercages of the zeolite. 29Si, 27Al-MAS NMR and in situFT-IR spectra reveal a new crystallization mechanism. The mesostructure and nano-supercages in the zeolite result from the bond-blocking action during the crystal growth. The zeolite has connatural micropore and ordered mesopore systems within the zeolite particles. The mesoporosity of the mesoporous zeolite can be rationally controlled by the degree of silanizing. The diffusion rate of hydrated Mg2+ in the synthesized submesoporous zeolite is 170 times higher than in a traditional zeolite at 308 K.

Liquid-phase epoxidation of styrene with atmospheric O2 was conducted over CoAPO-5 molecular sieves. The catalytic performance of CoAPO-5 can be significantly improved by alkali metal salt impregnated on it, and styrene conversion and selectivity to styrene oxide reached 85% and 69% respectively when CsCl was impregnated on it. The catalyst was recyclable and exhibited similar catalytic activity and selectivity even after three catalytic reaction cycles.

A series of nanosized ZSM-5 zeolite samples with intracrystalline mesopores has been synthesized using organosilane functioned fumed silica as silica source and tetrapropylammonium hydroxide as microporous structure directing agent. The organic moiety linked on the surface of fumed silica blocks the growth of zeolite crystal, forming the nanosized zeolite crystal and intracrystalline defects inside the nano-crystal. The formation of the mesopores is by bond-blocking function in crystallization. The XRD results indicate that the samples are high crystalline ZSM-5 and the TEM images show that the samples are nanosized with the size ca. 20 nm and the intracrystalline mesopores about 3 nm exist inside the nanosized crystal.Highlights► Nanosized ZSM-5 zeolite with intracrystalline mesopores was first prepared. ► The formation of the mesopores is by bond-blocking function in crystallization. ► The intracrystalline mesopores result in a spread hierarchical zeolite. ► The organic functioned silica source is essential for such material.

A zeolite composite composed of ZSM-5 and β-zeolites has been synthesized by a procedure of the nucleation and crystallization of ZSM-5 zeolite in the hollow β-zeolite. The property of β-zeolite crystals with aluminum-poor interior and aluminum-rich outer rim results in silicon extraction favorably in the aluminum-poor bulk rather than the aluminum-rich external surface. Subsequently, alkaline treatment of β-zeolite crystals during the second-step synthesis leads to a preferential dissolution of the aluminum-poor center and the formation of hollow β-zeolite crystals. ZSM-5 zeolite crystals are therefore embedded and grown within the hollow β-zeolite. The catalytic activities of Co-Hβ, Co-HZSM-5 and Co-HZSM-5/BEA are investigated during the reaction of methane catalytic reduction NO in the presence of O2.

A series of CoOx/SiO2 catalysts has been prepared by the sol–gel method and characterized with XRD, N2 adsorption/desorption, diffuse reflectance UV–vis spectroscopy, Raman spectroscopy as well as TPR techniques. This type of material is highly active and selective for the epoxidation of cyclooctene with atmospheric molecular oxygen. Although all the catalysts attained at different pH values are amorphous, their catalytic activities are remarkably different because the pH values influence not only the coordination state of Co species but also the textural structures of the prepared catalysts, in which CoOx/SiO2 obtained at pH below 5 is highly active and selective for the epoxidation of cyclooctene with atmospheric O2. The prepared CoOx/SiO2 catalysts are highly stable and can be recycled at least four times without significant loss of activity and selectivity.

A hierarchical porous zeolite composite possessing β-zeolite cores and Y-zeolite polycrystalline shells (denoted as BFZ) is synthesized by a two-step hydrothermal crystallization procedure and characterized by X-ray diffraction (XRD), N2 adsorption−desorption, scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM), selected area electron diffraction (SAED), energy-dispersive spectrometry (EDS), NMR, intelligent gravimetric analyzer (IGA), and in situ infrared (IR) spectrometry of pyridine. The results show that a hierarchical pore structure with the pore size centered around 6.9, 10.3, and 16 nm is created in the composite. A more than 2 orders of magnitude gas transport improvement is, therefore, achieved in the composite as compared with the corresponding physical mixture. The conversion of liquid-phase hydrogenation of benzene over H-BFZ supported by 3 wt % Ru is much higher than those over H-Y or H-β-zeolites supported by the same Ru loading due to the improved diffusion and acid accessibility as well as the enhanced Ru dispersion because of the introduction of hierarchical pores.

Cu-based adsorbents for CO adsorption were efficiently prepared by impregnation activated carbon (AC) with aqueous solution of copper (II) chloride and copper (II) carboxylate. The effects of preparation condition on CO adsorption capacity of the adsorbents were investigated. Characterization of the adsorbents by XRD and N2 adsorption at 77 K showed that cupric salts were completely converted to highly dispersed CuCl on activated carbon after pre-activation, resulting in the stoichiometric adsorption by the coordination of CO with Cu(I). The resulting adsorbents displayed high adsorption selectivity and good adsorption–desorption reversibility for CO with the small adsorption heat, and exhibited broad prospects for the selective separation of CO from mixture gas containing CO2, CH4 and N2 by pressure swing adsorption.Graphical abstractThe high CO adsorption selectivity on the Cu-AC adsorbent has promised the effective separation of CO from mixture gas containing CO2, CH4 and N2 by PSA.Research highlights▶ A CuCl/AC adsorbent was prepared by stoichiometrically reaction of copper (II) salts. ▶ Monolayer CuCl was dispersed on activated carbon to capture CO selectively. ▶ The Cu-based adsorbent has the superior adsorption/desorption capability for CO. ▶ The preparation route is suited to industrial manufacture of the adsorbent.

Zeolite-encapsulated transition metal complexes of SALEN [N, N′-bis(salicylidene) ethylenediamine] have been used as catalysts of oxidation reactions of hydrocarbons with oxidants including dioxygen. But in these processes molecular oxygen as oxidant did not show good activity compared with other oxidants such as TBHP, PhIO and H2O2. In order to evaluate the catalytical effect of the hybrid materials on the process of activating molecular oxygen, zeolite-encapsulated M(Co, Fe, Mn)(SALEN) complexes modified glassy carbon electrodes [M(SALEN)/Y/GCEs (M = Mn, Fe, Co)] were prepared and used as electrocatalysts of oxygen reduction reaction (ORR). The electrocatalytic reduction of dioxygen, thus, was investigated by cyclic voltammetry (CV) and chronocoulometry (CC) at glassy carbon electrodes (GCEs) modified with metal (Co, Fe, Mn) complexes of SALEN encapsulated inside NaY in pH 6.90 aqueous solutions. The results have shown that the M(SALEN)/Y/GCEs (M = Mn, Fe, Co) exhibited efficient electrocatalytic activity towards dioxygen reduction with reduced overpotentials of about 505 mV, 393 mV and 397 mV for Co(SALEN)/Y, Fe(SALEN)/Y and Mn(SALEN)/Y, respectively, lower than bare GC electrode and enhanced peak currents. The electroreduction of O2 on these modified GCEs is an irreversible and diffusion-controlled process. The transferred number of electrons and the transfer coefficient for dioxygen reduction reaction were determined by CV and CC. These results suggest that zeolite-encapsulated M(Co, Fe, Mn)SALEN complexes can efficiently activate molecular oxygen by decreasing the overpotential and increasing current of oxygen reduction reaction. And dioxygen is reduced to form water in the process. The significance of this work lies in evaluating the catalysis of the hybrid catalysts for oxidation reaction by electrochemical techniques.

A granular composite material containing zeolite and activated carbon was prepared from elutrilithe and pitch powder. The process consisted of the following steps: pyrolysis of pre-shaped raw material, carbon dioxide activation, and subsequent hydrothermal transformation of aluminosilicate in alkaline solution. The resulting material exhibited hierarchical pore structure with high surface area and porosity as characterized by X-ray diffraction and nitrogen adsorption. The addition of pitch powder enhanced mechanical strength of the granular composite and adjusted zeolite-to-carbon ratio. Further, effects of preparation parameters on porosity of activated carbon and phase composition of zeolite were investigated. During carbon dioxide activation, porosity evolution resulted in the formation of new micropores in the carbon precursor and further enlarged original micropores; and the textural characteristics of activated carbon mainly depended on temperature and activation time. Zeolite with high crystallinity was obtained with appropriate alkalinity, temperature and hydrothermal synthesis time.

A chiral ruthenium complex [(1S, 2S)-DPEN]–RuCl2(PPh3)2 (DPEN = 1,2-diphenylethylenediamine, PPh3 = triphenylphosph-ine) was encapsulated in the channel of Al-MCM-41 by electrostatic adsorption and 1,1-dichlorosilacyclobutane modification. The prepared heterogeneous catalyst showed the same catalytic activity and enantioselectivity as the corresponding homogeneous catalyst in the asymmetric hydrogenation of acetophenone, and could be reused at least seven times without significant loss of catalytic activity and enantioselectivity.

A zeolite composite with MFI and MOR zeolite structures (denoted as MMZ) was prepared by a two-step hydrothermal crystallization, and characterized by X-ray powder diffraction, nitrogen adsorption–desorption, scanning electron microscopy and in situ IR spectrometry of pyridine and 2,6-dimethyl pyridine. The acid catalysis of the composite MMZ was investigated during the catalytic cracking of n-octane and cumene. The results showed that a hierarchical pore system was created in the zeolite composite improving the accessibility of acid sites and diffusivity in the composite material. The diffusivity in the composite was about seven times higher than in the corresponding physical mixture, and the acid accessibility in the composite was 3.4 times as much as in the physical mixture when 2,6-dimethyl pyridine was used as the probe molecule. The conversion of cumene on H-MMZ was three times larger than that on the physical mixture at 423 K.

A superacid mesostructured catalyst was directly synthesized by adding sulfuric acid to mesoporous zirconia–silica synthesis mixtures, and was characterized by HRTEM, XRD, UV–Vis, nitrogen sorption, NH3–TPD, and Pyridine–FTIR. The XRD patterns and electron diffraction micrographs of the calcined samples showed the ordered mesoporous structure and tetragonal crystalline in frameworks. The ammonia TPD, pyridine in situ FTIR, and paraffin isomerization illustrated a new acidic property of the samples. The synthesis of the mesoporous materials, which have stable crystalline frameworks, high surface area, and strong acidity, is very likely to have important technological implications for catalytic reactions of large molecules.TEM images of the calcined mesoporous catalyst MSCx (x=1.1), in which no aggregated ZrO2 particles can be observed. The corresponding electron diffraction (insets in figures) indicated the final product was a mesoporous material with a crystalline framework.

The new macroscopic-scale SBA-15 spheres with diameter of 0.2–0.5 mm are prepared by a sol–gel method, in which the tetrabutylorthosilicate (TBOS) is used as silicon source and triblock copolymer (P123) and polyoxyethylene octylphenol ether (OP-10) are used as templates. The resulting spherical samples are characterized by XRD, N2 adsorption–desorption, TEM and SEM methods. The results show that the inner structure of SBA-15 macrospheres has macroporous channels (0.5 μm) and mesoporous skeleton (4–5 nm). These SBA-15 macrospheres with the hierarchical pore structure demonstrate high absorption capacity for Emodin molecules.

A zeolite composite Y/Beta with core-shell structure was synthesized by adding tetraethylammonium bromide (TEABr) exchanged NaY zeolite into the pre-reacted mixture used to prepare Beta zeolite. The composite was characterized by XRD, N2 adsorption, SEM, and FTIR spectra of pyridine. The results show that the composite is composed of a core zeolite Y and a shell of intergrown zeolite Beta crystals, representing dual microporous structures of both Y and Beta zeolites and a new mesoporous structure. The composite has a high activity in n-octane catalytic cracking because of the formation of intergrowths and the change of acidity due to the distorted interface and surface defects.

Super-acid catalyst, SO42−/ZrO2–SiO2, with high zirconium loading was synthesized and the nature of the surface acid was investigated by FT-IR of pyridine adsorption. With the increasing ZrO2 content, the Lewis and Brønsted acid sites increased and reached the maximum when Zr/Si (molar ratio) = 1.3. The sample with Zr/Si = 1.3 showed the strongest IR adsorption band in the S=O stretching region (1,300–1,400 cm−1). Pyrosulfate and monosulfate species existed on the surface of the catalysts and the acidic strength could be enhanced by induction effect of their S=O groups. And there were two kinds of Brønsted acid sites on the surface of the catalysts.

Mesoporous silica-pillared montmorillonites (SPMs) were prepared based on cation-exchange, gallery-templated synthesis method, and the post-synthesis treatment using ammonia, and characterized by powder X-ray diffraction (PXRD), thermogravimetric analysis (TGA), and N2 adsorption–desorption. The results showed that ammonia played a very important role in the formation of the mesoporous materials; the calcined SPMs indicated a BET surface area of 511 m2/g and average pore size of 3.1 nm by adjusting the ammonia treating temperature at 110 °C. The formation of SPMs was discussed and its progressing mechanism was suggested.

Zeolite-activated carbon (ZEOAC) extrudates were synthesized from natural elutrilithe through a two-step process consisting of the chemical activation of elutrilithe with K2CO3 at 800°C followed the hydrothermal transformation in NaOH solution. During the chemical activation, carbon in elutrilithe was activated, and the kaliophilite crystalline phase with framework structure of linked (Si, Al)O4 tetrahedra was formed simultaneously, which was then converted into zeolite A in alkaline medium. The as-synthesized samples were characterized by thermal gravimetric and differential thermal analyses (TG/DTA), N2 adsorption, X-ray diffraction (XRD), scanning electron microscopy (SEM) and adsorptive capacities for water and hexane. The results show that this new material ZEOAC possesses the typical characteristics of zeolite and activated carbon, micro- and mesoporous structure, hydrophilic and hydrophobic properties.

The Zr-SBA-15 mesoporous materials with high Zr/Si ratio (0–2.32) were first synthesized directly using zirconium nitrate and tetraethyl orthosilicate as precursor, displaying higher thermal stability after activated at 600 °C. 29Si NMR spectra revealed the part existance of ZrO2 in the framework of SBA-15. After sulfated, the SO42-/Zr-SBA-15 exhibited high activity in the isomerization of n-pentane at 35 °C, and the conversion of n-pentane reached 93.9% after reacting 180 min with the SO42-/Zr-SBA-15 of Zr/Si = 1.3, which was higher compared with the bulk sulfated zirconia material and the SBA-15 modified with SO42-/ZrO2 by incipient wetness method.

Zirconium-based MOFs of the UiO family have attracted considerable attention due to their high thermal, chemical and mechanical stability. With the aim of further exploring the applications of zirconium-based UiO-66 in acid-catalyzed reactions and elucidating the effects of the defects in UiO-66 materials on their catalytic performances, in this work, a series of zirconium-containing UiO-66 samples were synthesized by varying the synthesis temperatures and BDC/Zr (terephthalic acid/ZrCl4) ratios in the synthesis system. The synthesized UiO-66 samples were characterized by X-ray diffraction (XRD), N2 adsorption-desorption, scanning electron microscopy (SEM), thermogravimetrical analysis (TGA), temperature-programmed desorption of NH3 (NH3-TPD). Their catalytic performances were investigated in transesterification of tributyrin and soybean oil with methanol. The results showed that UiO-66 samples with different amounts of defects could be successfully prepared by varying the synthesis temperatures and/or the BDC/Zr ratios used in the synthesis system. The catalytic activities of the UiO-66 materials greatly depended on their linker defects and enhanced with the increase of the defect amount. The UiO-66 was an efficient catalyst for transesterification of tributyrin and soybean oil with methanol under mild reaction conditions and its catalytic activity was comparable to other solid acid catalysts reported in the literatures. The UiO-66 catalyst was relatively stable and could be reused.Download high-res image (124KB)Download full-size imageUiO-66 is an efficient and reused catalyst for transesterification of tributyrin and soybean oil with methanol.

Ordered mesoporous copper incorporated Al2O3 (Cu/Al2O3) with high Cu dispersion were prepared by a facile solution combustion synthesis method using aluminum nitrate and copper nitrate as oxidants and urea as fuel. It is a facile and green route to synthesize catalysts for dimethyl ether directly from syngas. Cu/Al2O3 catalysts were characterized by XRD, N2 adsorption–desorption, SEM-EDS, and H2-TPR. The results indicate that the catalysts obtain an ordered mesoporous structure and copper is homogenously dispersed. The mesoporous Cu/Al2O3 catalysts were utilized as bifunctional catalysts in syngas to dimethyl ether reaction (STD). The copper content affects the catalytic performance in STD reaction. The CO conversion and DME selectivity of Cu/Al2O3 with 15% copper molar ratio achieve 52.9% and 66.1%, respectively. Moreover, the mesoporous Cu/Al2O3 catalysts show excellent stability in STD reaction.Highly dispersed copper incorporated Al2O3 was synthesized by a solution combustion synthesis method and utilized for syngas to dimethyl ether reaction.Download high-res image (149KB)Download full-size image

•The sulfated zirconia catalyst was prepared by a novel one-pot synthesis route.•The more acid sites were found to attach on the surface of tetragonal zirconia.•The catalyst exhibited excellently catalytic activity.•The catalysts calcined at 500 °C showed 100% yields for the transesterification.•The catalysts were well applied in biodiesel production.A sulfated zirconia catalyst has been prepared by a novel one-pot vapor-controlled synthesis route using ammonium persulphate as sulfate agent. A possible formation mechanism of the catalyst is proposed. The effect of calcination temperature and S/Zr molar ratio on the structural, textural and catalytic properties of the prepared catalyst were investigated in detail using X-ray diffraction (XRD), N2 adsorption–desorption, ammonia temperature programmed desorption (NH3-TPD), Fourier transform infrared spectroscopy (FTIR) and a scanning electron microscope (SEM) which was equipped with an energy dispersive spectroscope (EDS). The results indicated that the samples calcined at 500 °C possessed zirconia of pure tetragonal structure, more content of sulfur and better distribution of acid sites on the surface of zirconia compared with the samples calcined at 600  °C at fixed S/Zr molar ratio. Moreover, they showed excellent catalytic activity with 100% yields of biodiesel for the transesterification of soybean oil with methanol.

Hierarchically porous composite zeolite (BFZ, with Beta zeolite cores and Y zeolite polycrystalline shells) was employed as the methanol dehydration catalyst in the direct synthesis of dimethyl ether (DME) from syngas in a fixed-bed reactor. The correlation between the catalytic activity and the textural and acid properties of the dehydration catalyst was investigated. The results indicate that the composite zeolite of H-form (HBFZ) exhibits moderate acid strength and meso-porosity, which is responsible for the high activity of CO hydrogenation. For the direct synthesis of DME from CO hydrogenation over the physical mixture of commercial CuO/ZnO/Al2O3 catalyst (CZA) and the H-form zeolites (HBFZ or HY), CZA/HBFZ exhibits higher activity and stability than CZA/HY. Under 250°C, 5.0 MPa and 1500 h−1, the conversion of CO and the selectivity to DME over CZA/HBFZ achieve 94.2% and 67.9%, respectively.

Selective catalytic reduction of NO by methane in the presence of excess oxygen over CoH-FBZ zeolite composite catalyst has an advantage over the physical mixture of CoH-Y and CoH-Beta. The interaction between NO or NO+O2 and the catalyst revealed by adsorption and temperature-programmed desorption (TPD) technique, results directly in the effect of the topological structure of supports upon the stability of N- and O- species on the surface of the catalysts. The NO+O2-TPD profile of the CoH-FBZ catalyst exhibits two NO2 desorption peaks at 630 K and 660 K, respectively. This indicates that new adsorption centers for –NOy are formed over the CoH-FBZ and adsorbed more stably on CoH-FBZ than on CoH-Y or CoH-Beta. The synergism of the newly formed Co sites and the new strong acidic sites contributes to the novel CH4-SCR catalytic properties of the CoH-FBZ catalysts.

A series of solid acid SO42−/ZrO2-SiO2 catalysts with a fixed Zr/Si molar ratio of 1.1 were successfully synthesized in one-pot through changing the H2SO4/HCl volume ratio during the self-assembly process. X-ray diffraction (XRD), UV-visible DRS, and high resolution transmission electron microscopy (HRTEM) results demonstrate that all the resultant catalysts exhibit a highly ordered 2D hexagonal mesostructures with zirconia particles of homogenously distributed tetragonal nanocrystallites in mesoporous walls. N2 adsorption and pyridine in-situ Fourier-transformed infrared spectra (FT-IR) further reveal that the surface area, pore volume, pore diameter and the relative strength of Lewis and Brønsted acidic sites of resultant catalysts can be controlled by tuning the H2SO4/HCl volume ratio during the synthesis. Different from pure mesoporous SBA-15 material, the mesoporous SO42−/ZrO2-SiO2 materials prepared in this work exhibit high structural stability and catalytic activity in n-pentane isomerization, which is attributed not only to hydrochloric acid that facilitates the formation of mesoporous silica but also to sulfuric acid that helps to stabilize the structure of catalysts and produce acid sites. The methods proposed in this work provide an important approach to synthesize ordered solid acid catalysts with high stability and potential applications in various acidic-catalyzed reactions.

The activity and stability of the Co-Beta catalyst were investigated for the selective catalytic reduction (SCR) of NO by CH4 with and without the presence of SO2. The Co-Beta catalyst exhibited good stability during a long-term test of 30 h for the SCR reaction in the absence of SO2. The addition of 78 ppm SO2 caused a decrease in NO conversion, but the loss of catalytic activity was completely reversible after removal of SO2 from the feed. The characterization of fresh and used Co-Beta catalyst samples by XRD, UV–vis spectroscopy, H2-TPR, NO-TPD and FTIR spectroscopy was carried out to study the effect of SO2 on Co sites. UV–vis spectroscopy and H2-TPR analyses showed that the main Co species present in the catalyst were negligibly reducible Co2+ ions located at ion exchange sites and easily reducible polynuclear and/or nanosized Co oxide phases. The poisoning effects of SO2 on the different Co species were different. The poisoning of SO2 was irreversible for the Co2+ ions at the exchange sites but was completely reversible for the polynuclear and/or nanosized Co oxide species. The reversible deactivation was strongly related to the redox properties of the surface Co species. The polynuclear and/or nanosized Co oxide species were found to be active sites in the SCR reaction.Graphical abstractDownload high-res image (78KB)Download full-size imageHighlights► Co-Beta catalyst exhibited good stability in the SCR of NO with methane. ► The poisoning of SO2 on different Co species has different poisoning mechanism. ► The poisoning of SO2 on nanosized Co oxide species was completely reversible. ► The Co oxide species are found to be active sites in the SCR reaction.

•A super-microporous crystalline alumina material.•The material with high surface area and thermal stability.•The material with narrow pore size distribution of 1.7 nm.•The material was synthesized by an economic template AEO-7.•High CH4 -SCR-NO activity.Super-microporous alumina (pore size between 1 and 2 nm) with polycrystalline walls and high surface area (more than 650 m2/g) was synthesized successfully via an evaporation induced self-assembly (EISA) pathway using readily available and inexpensive nonionic surfactant fatty alcohol polyoxyethylene ether (AEO-7) as the template. N2 adsorption-desorption results showed that the obtained materials are super-microporous when removing the template at 400 °C, then if the calcination temperature increase from 600 °C to 1000 °C, a breakdown of the walls separating adjacent pores allows the transformation to mesopores (pore size > 2 nm). FTIR pyridine adsorption and NH3-TPD measurement suggested the presence of strong Lewis acid sites. Transmission electron microscopy (TEM) measurements indicated that the alumina possesses the disordered “wormhole-like” super-microporous structure with polycrystalline walls. Loaded with copper, the catalyst exhibited outstanding activity in the selective catalytic reduction of NO with methane and could achieve a NOx conversion 100% when the reaction temperature is over 600 °C.

An ordered mesoporous zeolite LTA is prepared by using organofunctionalized silica as Si-source. The mesoporous zeolite LTA has nano-cages of 3 nm interconnected to each other through 0.8–1.2 nm channels. A Jacobsen salen complex can be encapsulated successfully in the supercages of the zeolite. 29Si, 27Al-MAS NMR and in situFT-IR spectra reveal a new crystallization mechanism. The mesostructure and nano-supercages in the zeolite result from the bond-blocking action during the crystal growth. The zeolite has connatural micropore and ordered mesopore systems within the zeolite particles. The mesoporosity of the mesoporous zeolite can be rationally controlled by the degree of silanizing. The diffusion rate of hydrated Mg2+ in the synthesized submesoporous zeolite is 170 times higher than in a traditional zeolite at 308 K.

A mesoporous beta zeolite was hydrothermally prepared directly by silanizing silica without any mesoporous template via the bond-blocking principle. Si–C bond-blocking arose during the crystalline growth. The crystallization took more than 10 days, but the material had a fairly stable structure and could even be processed up to 32 days later in the hydrothermal system. XRD, N2-adsorption/desorption and TEM/SEM characterization of the materials indicated that the beta zeolite is truly a sponge-like mesoporous zeolite with a BEA topological structure, which consists of self-sustaining macroscopic sized zeolitic aggregates assembled from nanosized crystalline domains of beta zeolite with intracrystalline mesopores. The mesoporous beta zeolite possessed an extremely large external surface area and adjustable mesoporosity. Compared to conventional beta zeolite, FTIR results of pyridine (Py) and 2,6-di-tert-butylpyridine (DTBPy) demonstrated an increase of the Lewis-site contribution and a large improvement for the accessibility of bulky molecules in the mesoporous beta zeolite. Finally the mesoporous beta zeolite exhibited significant activity in the transesterification reaction of triolein to afford methyl oleate (biodiesel) due to the accessibility increase and diffusion-limitation reduction of large lipids to acid sites in the H-beta zeolite framework.