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A feasible approach was developed for the synthesis of ordered mesoporous SBA-15-type materials using coal fly ash (CFA) as raw material. In the proposed approach, CFA was, firstly, activated by subcritical water with the addition of NaOH, which allowed an efficient extraction of silicon species from CFA under strong acidic conditions at near room temperature. Subsequently, in the synthesis system, using silicon extraction solution as the silicon precursor, the introduction of anhydrous ethanol as a co-solvent effectively inhibited the polymerization of silanol species and promoted their collaborative self-assembly with surfactant molecules by enhancing the hydrogen bond interactions. The resultant SBA-15 material had a high purity, high specific surface area (1014 m2/g) and pore volume (1.08 cm3/g), and a highly ordered mesostructure, and, therefore, exhibited an excellent removal efficiency (90.5%) and adsorption capacity (160.8 mg/g) for methylene blue (MB) from simulated wastewater. Additionally, the generation of surface acid sites from the homogenous incorporation of Al atoms onto the mesoporous walls of SBA-15 combined with the perfect retention of the ordered mesostructure endowed the obtained Al-SBA-15 material with a further boost in the removal performance of MB. The MB removal efficiency can reach ~100%, along with a maximum adsorption capacity of 190.1 mg/g. [ABSTRACT FROM AUTHOR]

Mesoporous alumina (MA) materials with outstanding textural properties have been synthesized by a facile approach, and were evaluated as supports of Pt-based catalyst for methylcyclohexane dehydrogenation. At 300 °C, the resultant catalyst demonstrates a much higher activity with a maximum hydrogen evolution rate of 2081 mmol/g Pt /min in comparison with the state-of-the-art alumina supported Pt catalysts. Interestingly, even after a long-time reaction of 100 h or regeneration, more than 80% of original activity was still maintained. The superior catalytic performance of the obtained catalyst is associated with the high specific surface area and large mesoporous size of support MA, thus benefiting the increase in the number of Pt active sites and efficiently inhibiting the formation of coke deposition during the reaction. Our contribution has provided a rational design strategy for highly efficient and stable dehydrogenation catalysts, which is a key for the utilization of methylcyclohexane-toluene system in hydrogen storage technology. [Display omitted] • A confined hydrolysis-condensation approach. • Mesoporous alumina with excellent textural properties. • Pt-based catalyst with highly homogenous dispersion of Pt. • Improved catalytic performance for dehydrogenation of methylcyclohexane at low temperature. [ABSTRACT FROM AUTHOR]

A solvothermal-assisted evaporation-induced self-assembly (SA-EISA) approach has been developed for the synthesis of ordered mesoporous alumina (OMA) materials with high thermal stability and improved performance in catalysis. In conventional EISA process, the evaporation step is accompanied by the hydrolysis of organic aluminum precursors, thus the evaporation conditions have significant influences on the reaction and the final structure of OMA. In our approach, the solvothermal treatment step promotes the complete hydrolysis of aluminum precursors and produces partially condensed cluster-like aluminum hydroxyl species, which allows the formation of OMA in a broad range of evaporation conditions. Compared to mesoporous alumina obtained by conventional EISA process, OMA materials prepared by SA-EISA approach exhibit higher specific surface area, pore volume and thermal stability. When used as supporting material s for vanadium oxide catalyst, OMA materials obtained by the SA-EISA approach exhibit excellent activity, selectivity and stability for ethylbenzene dehydrogenation with carbon dioxide as a mild oxidant. Our contribution has provided new understanding in the synthesis of OMA materials with improved performance for catalytic applications. [ABSTRACT FROM AUTHOR]

Abstract Ordered mesoporous Mg Al composite oxide-supported K catalysts (x K/OMMA) were prepared and used for soybean oil transesterification with methanol. The prepared x K/OMMA demonstrated a much higher soybean oil conversion (up to 97.0%) along with a 99.8% selectivity to fatty acid methyl ester and a desirable reusability, compared with K-based catalysts prepared with the same K loading and using ordered mesoporous alumina or mesoporous Mg Al mixed oxide as support. The superior catalytic performance of x K/OMMA is associated with the excellent structural and surface properties of support OMMA, thus benefiting the generation of catalytically active sites and their highly homogenous dispersion. Graphical abstract Unlabelled Image Highlights • Ordered mesoporous Mg Al composite oxide-supported potassium for biodiesel production. • Excellent support properties benefiting the generation of basic K species. • A highly homogenous dispersion of catalytically active sites on the surface of support. • A superior catalytic activity for soybean oil conversion along with a desirable reusability. [ABSTRACT FROM AUTHOR]

Ordered macro-mesoporous Mg-Al composite oxides (denoted as OMM-MA-x) with tunable macropore size and highly homogenous distribution of Mg have been synthesized via a confined evaporation induced self-assembly method, in which triblock copolymer F127 and polystyrene colloidal crystals are utilized as templates for ordered mesoporous and macroporous structures, respectively. The resultant OMM-MA-x materials exhibit a much more ordered 2D hexagonal mesostructure constituting wall skeleton of ordered macropores and more excellent textural properties than those of ordered macro-mesoporous alumina materials. More importantly, both ordered mesostructure and macroporous structure of OMM-MA-x can be well maintained even after thermal treatment at 900 °C or pressure treatment at 15 MPa. [ABSTRACT FROM AUTHOR]

Highly ordered mesoporous magnesium-aluminium composite oxides (denoted as OMMA-x) with a variety of n Al / n Mg 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 Mg O Al 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 m 2 /g even after thermal treatment at 1000 °C. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

[Display omitted] • Ordered mesoporous Ti-Al composite oxides with highly homogenous dispersion of Ti. • Improved catalytic performance for oxidative dehydrogenation of ethylbenzene with CO 2. • The bridging oxygen in surface Ti4+ O Al3+ bonds as the critical active sites. • Surface chemisorbed oxygen species enhancing the reactivity of active sites. Ordered mesoporous Ti-Al composite oxides (OMTA-x) with variable Al/Ti atomic ratios have been prepared by a facile approach, and were evaluated as catalysts for oxidative dehydrogenation of ethylbenzene to styrene with CO 2 (CO 2 -ODEB). Compared to Al 2 O 3 -supported titania catalyst, the resultant catalysts OMTA-x displayed inspiringly improved catalytic performance. For example, catalyst OMTA-2 demonstrated notable activity up to 20 h with maximum styrene yield of 69.4%, even after five times regeneration by calcination. The superior catalytic performance of OMTA-x can be attributed to the highly homogenous dispersion of Ti, the obviously improved surface acidity and redox properties, and the excellent textural and structural properties. The bridging oxygen in the surface Ti4+ O Al3+ bonds with enhanced reactivity with H were concluded as the critical active sites for dehydrogenation of ethylbenzene, and new understanding for the development of TiO 2 -based catalysts with superior catalytic activity, stability, and reusability for CO 2 -ODEB was provided. [ABSTRACT FROM AUTHOR]

Abstract: 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 6h. 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. [Copyright &y& Elsevier]

Abstract: Highly ordered mesoporous Al-SBA-15 with high aluminum content and high hydrothermal stability has been synthesized by a new pH-adjusting and high-temperature hydrothermal treatment approach. Thus-prepared samples were characterized by X-ray fluorescence spectroscopy, X-ray powder diffraction, 27Al nuclear magnetic resonance spectroscopy, N2 adsorption–desorption, temperature-programmed desorption of ammonia, Fourier transformed infrared spectroscopy with pyridine adsorption, temperature-programmed reduction with hydrogen, and high-resolution transmission electron microscopy. The results showed that Al-SBA-15 had high aluminum loading (with its molar Si/Al ratio of 5.1, similar to that of the initial gel mixture) and homogenously distributed Al species in the walls. Moreover, the product showed extremely high hydrothermal stability (with only a 15.2% decrease in surface area after steaming at 800°C for 5h) and moderate acidity. An Al-SBA-15-supported NiW hydrodesulfurization catalyst was prepared and evaluated using dibenzothiophene hydrodesulfurization. Compared with γ-Al2O3- and SBA-15-supported catalysts, the Al-SBA-15-supported NiW catalyst showed outstanding hydrodesulfurization activity. [Copyright &y& Elsevier]

Abstract: Highly ordered mesoporous silica and aluminosilicate materials with extremely high hydrothermal stability have been synthesized successfully at a high hydrothermal treatment temperature of 200°C by using inexpensive sodium silicate and sodium aluminate as the silica source and alumina source, respectively. The resultant mesoporous materials possess a hexagonal mesostructure and extraordinary stability towards the steam treatment at 800°C for 2h. In addition, the direct incorporation of Al into the mesoporous framework can further enhance the hydrothermal stability of ordered mesoporous materials. Our contribution provides a commercially important approach to synthesize ordered mesoporous materials with highly hydrothermal stability, which may find potential applications for the catalytic cracking in the petroleum industry. [Copyright &y& Elsevier]

A novel heterogeneous catalyst has been developed by immobilizing Ru complexes on layered double hydroxide (LDH) via an electrostatic adsorption method. The prepared hybrid was characterized by a series of physical and chemical techniques, and the results confirmed the successful immobilization of the Ru complexes on the LDH support. The prepared heterogeneous Ru catalyst was found to be more enantioselective than the corresponding homogeneous analogue in the asymmetric hydrogenation of acetophenone and its ee value was 10% higher than that of the homogeneous analogue. Furthermore, the prepared heterogeneous catalyst could be recovered easily and reused at least six times without a significant loss in catalytic activity and selectivity. Density functional theory (DFT) computations revealed the influence of LDH layer on Ru complexes and the enantioselectivity of the immobilized Ru complexes in asymmetric hydrogenation of acetophenone. [ABSTRACT FROM AUTHOR]

Ordered mesoporous alumina (OMA)-supported vanadia catalysts with different vanadium loading (denoted as n V/OMA) were employed for ethylbenzene dehydrogenation to styrene with CO 2 as soft oxidant, and a commercial γ-Al 2 O 3 -supported vanadia catalyst for comparison. The catalytic behavior depends strongly on the vanadium loading and the support properties. With an optimal V loading of 0.8 mmol/g-support, 0.8 V/OMA catalyst exhibits superior catalytic performance than that of 0.8 V/γ-Al 2 O 3 , which can be attributed to the excellent structural, textual, and surface properties of OMA support. The important roles played by OMA lies in stabilizing highly dispersed V 5+ active species and preventing the coke formation. [ABSTRACT FROM AUTHOR]

The structures of a series of 3D-SBA-15 materials have been systematically studied by X-ray diffraction (XRD), nitrogen sorption, and electron tomography (ET) techniques. All the 3D-SBA-15 materials possess an ordered 2D hexagonal mesostructure with similar cell parameters, while the pore size measured from nitrogen sorption increases with the hydrothermal treatment temperature, in some cases even larger than the cell parameter calculated from X-ray diffraction. Taking advantage of the ET technique, it is shown that there exist two types of pores in 3D-SBA-15 materials: one is the ordered channels associated with the hexagonal symmetry, and the other is locally disordered and randomly distributed merged pores. During the hydrothermal treatment events at various temperatures, the size of ordered channels changes little, while the volume fraction and the overall size of the latter type of pores increase and eventually become dominant. Thus, the attribution of the pore sizes obtained from nitrogen sorption analysis to which types of pores is synthesis condition dependent and ET is an important tool to answer this question. [ABSTRACT FROM AUTHOR]

Abstract: Macromolecule polyvinylpyrrolidone (PVP)-immobilized Pt nanoclusters supported on HBeta, HY, NaY and SiO2 catalysts (signed as PVP-Pt/S) prepared by the alcohol–water reduction method are examined for their catalytic performance in the two step conversion of methane to higher hydrocarbons and compared with corresponding supported Pt catalysts (noted as Pt/S) prepared by the general incipient wetness impregnation method. The nature of the support affects the formation of hydrocarbons, by influencing the electronic state of Pt in catalysts Pt/S. The hydrocarbon amounts of methane conversion on PVP-Pt/S catalysts do not depend greatly on the supports and but binding energy of supported Pt clusters. Compared with the Pt/S catalysts, PVP-Pt/S catalysts have such characteristics as: (1) a well-dispersed and uniform particle size which can be controlled by adjusting the added amount of PVP; (2) a diminished interaction between the metal particle and support. This class of catalyst, therefore, may be expected to study the effect of particle size upon the catalytic activity and selectivity. The catalytic results combined with TEM over PVP-Pt/HBeta with various ratios of PVP to platinum show that the activity of catalysts increases for methane conversion with decrease of particle size, and the distributions of C2+ products vary in favour of the heavier hydrocarbons as the particle size increase. [Copyright &y& Elsevier]

Flower-like mesoporous sulfated zirconia nanosheets (SZNs) were developed by thermal decomposition of in situ sulfated Zr-MOFs for the first time. The sulfated Zr-MOFs act as both a morphological template and zirconium and sulfate sources. The amounts of SO42− in the synthesis system of UiO-66 greatly affected the morphology of sulfated Zr-MOFs via a coordination modulation method. The flower-like sulfated Zr-MOF nanosheets were obtained as the S/Zr ratio increased to 0.5. The calcination temperature has a great influence on the structural properties and catalytic performances of sulfated zirconia nanosheets other than morphology. Sulfated zirconia nanosheets (SZN-500) obtained by calcination at 500 °C had a large surface area (186.1 m2 g−1) and strong bonding between sulfate and zirconia atoms and exhibited a good catalytic activity and reusability for the transesterification of tributyrin with methanol. This viable synthetic strategy can offer an alternative way to prepare functionalized metallic oxides with a specific morphology. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Micro-mesoporous alumina-zirconia nanocrystals are prepared by vapor-induced route. • The Al incorporation improves the textural properties of the composites. • The largest surface area of 313 m2/g is obtained. • The samples possess stable tetragonal structure of zirconia. • The samples show large pore volumes in the range of 0.18–0.39 cm3/g. Abstract Micro-mesoporous alumina-zirconia nanocrystals with controllable textural properties are prepared using triblock copolymer F127 as a template via one-pot vapor-induced pathway. The BET surface area and pore volume of the samples increase with rising aluminum content. When the Al/Zr molar ratio is 0.6, the sample exhibits highest surface area of 313 m2/g of which 118 m2/g in the form of micropores after high temperature calcination. Moreover, the incorporation of Al species enhances the structural stability of zirconia in tetragonal phase. [ABSTRACT FROM AUTHOR]

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 m 2 /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. [ABSTRACT FROM AUTHOR]

The super-microporous microcrystalline MgO-ZrO 2 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 CO 2 , and N 2 adsorption porosimetry were employed to characterize the nanocomposites. Nitrogen sorption isotherms revealed that these materials had large surface areas of more than 200 m 2 /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). [ABSTRACT FROM AUTHOR]

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), N 2 adsorption–desorption, ammonia temperature programmed desorption (NH 3 -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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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 m 2 /g and a large pore volume of 0.17 cm 3 /g after calcination at 400 °C. Even after calcination at 900 °C, the microporous structure remained, exhibiting a significant thermal stability. [ABSTRACT FROM AUTHOR]

UiO-66 supported metal catalysts have shown high catalytic activity and selectivity to cinnamyl alcohol (COL) in the selective hydrogenation (SHYD) of cinnamaldehyde (CAL), but the roles of missing-linker defects (MLDs) in UiO-66 on the catalytic performance of the UiO-66 supported metal catalysts have less been reported. Here, UiO-66 supports with the different amount of MLDs were used as the supports, and three series of UiO-66 supported Pt (Pt/U) catalysts were prepared by sol-impregnation, wet-impregnation as well as in-situ encapsulation methods, respectively. The influences of the MLDs in UiO-66 on the catalytic properties of the prepared Pt/U catalysts in the SHYD of CAL were investigated. The series of Pt/U-720 catalysts with the more MLDs showed higher CAL conversion and selectivity to COL than the corresponding Pt/U-F catalysts with fewer MLDs. The different preparing methods affect the location and dispersion of Pt species on UiO-66 supports and the metal-support interaction, but the location of the supported Pt species on UiO-66 is the critical factor affecting the catalytic properties of Pt/U catalysts. The presence of the MLDs in UiO-66 is the key to preparing UiO-66 supported Pt catalysts with high SHYD performance. [Display omitted] • Pt/UiO-66 with more defects exhibits higher CAL conversion and selectivity to COL. • The defect in UiO-66 is the key for improving catalytic performance of Pt/UiO-66. • Pt/UiO-66 prepared by the different methods was compared in CAL hydrogenation. • The work provides new insights on preparing Pt/UiO-66 for CAL hydrogenation. [ABSTRACT FROM AUTHOR]

Abstract: 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 30h for the SCR reaction in the absence of SO2. The addition of 78ppm 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. [Copyright &y& Elsevier]

In this work, a highly crystallized SSZ-13 (STM-24) was successfully synthesized with sodium silicate as silica source in the co-existence of seeds and a small amount of N,N,N- trimethyl-1-adamantanamine hydroxide (TMAdaOH, TMAdaOH/SiO 2 = 0.02). The TMAdaOH amount is about one-seventh of that used in the conventional synthesis method. The SSZ-13 samples synthesized by this method were characterized by XRD, SEM, N 2 adsorption/desorption, ICP, FT-IR, UV-Raman, NH 3 -TPD, 27Al and 29Si NMR, and compared with SSZ-13 synthesized by conventional method at TMAdaOH/SiO 2 = 0.14 (TMA-0.14-48). The results show that STM-24 and TMA-0.14-48 have comparable textural properties and acidity, except STM-24 shows a smaller particle size than TMA-0.14-48. Moreover, the SiO 2 /Al 2 O 3 ratios of SSZ-13 synthesized by this method are controllable in a wide range of 7.3–21.5. The synergistic effect between seeds and a small amount TMAdaOH is the key to successful synthesis of SSZ-13. Additionally, Cu-STM-24 and Cu-TMA-0.14-48 catalysts show similar catalytic performances in SCR reaction. The synthesis method reported in this work provides a new and alternative way for a low-cost and efficient synthesis of SSZ-13. [Display omitted] • SSZ-13 was synthesized in the presence of seeds and a small amount of TMAdaOH. • TMAdaOH amount in this method is just 1/7 of that used in the conventional method. • There is a synergistic effect between the seeds and a small amount TMAdaOH. • The synergistic effect is the key to successful synthesis of SSZ-13. [ABSTRACT FROM AUTHOR]

Co-containing catalysts supported on super-microporous Al 2 O 3 –ZrO 2 (denoted as Co/AZ(X)) with different Al/Zr molar ratio (X) were prepared by impregnation method, and they were applied to the dehydrogenation of ethylbenzene with CO 2 as soft oxidant. It was found that textural and chemical properties of Co/AZ(X) materials were strongly influenced by Al/Zr molar ratio. The catalytic performance of these materials highly depended on their physicochemical properties, and the 2.5Co/AZ(0.7) catalyst with an intermediate acidity, high surface area and high metal dispersion exhibited the best catalytic performance in the dehydrogenation of ethylbenzene with CO 2. • Co/Al 2 O 3 –ZrO 2 as an efficient catalyst for ethylbenzene dehydrogenation with CO 2. • The catalytic behavior of Co/Al 2 O 3 –ZrO 2 depended on its physicochemical properties. • 2.5Co/AZ(0.7) exhibited a better catalytic performance. [ABSTRACT FROM AUTHOR]

Ordered mesoporous Zr-Al composite oxide materials (denoted as OMZA-x) with different Zr contents have been synthesized by a solvent evaporation-inducing self-assembly procedure associated with a thermal treatment at 100 °C. A cooperative co-assembly process of amphiphilic triblock copolymer F127 molecules and inorganic hydroxyl species originated from the hydrolysis of Zr and Al precursors was proposed to explain the synthesis of OMZA-x. Compared to ordered mesoporous alumina prepared without introducing Zr species, the resultant OMZA-x exhibited a much more ordered mesostructure combined with a distinct increase in the pore volume and specific surface area. The highly homogenous doping of Zr into the mesopore walls together with the formation of Zr-O-Al bonds can effectively enhance the thermal and hydrothermal stability of OMZA-x. For instance, the ordered mesostructure and excellent textural properties of OMZA-6 prepared with the optimum atomic ratio of Al to Zr of 6 could be well maintained even after a high-temperature treatment at 1000 °C for 1 h or a hydrothermal treatment at 100 °C for 6 h. [ABSTRACT FROM AUTHOR]

Catalytic performance of Al‐MCM‐41‐supported vanadia catalysts (V/Al‐MCM‐41) with different V loading was investigated for oxidative dehydrogenation of ethylbenzene to styrene (ST) with CO2 (CO2‐ODEB). For comparison, pure silica MCM‐41 was also used as support for vanadia catalyst. The catalysts were characterized by N2 adsorption, X‐ray diffraction (XRD) pyridine‐Fourier‐transform infrared spectroscopy, H2‐temperature‐programmed reduction, thermogravimetric analysis (TGA), UV‐Raman, and diffuse reflectance (DR) UV–vis spectroscopy. The results indicate that the catalytic behavior and the nature of V species depend strongly on the V loading and the support properties. Compared with the MCM‐41‐supported catalyst, the Al‐MCM‐41‐supported vanadia catalyst exhibits much higher catalytic activity and stability along with a high ST selectivity (>98%). The superior catalytic performance of the present V/Al‐MCM‐41 catalyst can be attributed to the Al‐MCM‐41 support being more favorable for the high dispersion of V species and the stabilization of active V5+ species. Together with the characterization results of XRD, TGA, and DR UV–Vis spectroscopy, the deep reduction of V5+ into V3+ during CO2‐ODEB is the main reason for the deactivation of the supported vanadia catalyst, while the coke deposition has a less important impact on the catalyst stability. [ABSTRACT FROM AUTHOR]