Low-angle X-ray Diffraction Research Articles

Selective removal of copper (II) ions from aqueous solution using pyridyl-bridged mesoporous organosilica hybrid adsorbent

The incorporation of active functional groups into the mesoporous organosilica hybrid materials is efficient for various applications. A newly designed mesoporous organosilica adsorbent was prepared using diaminopyridyl groups bridged-(bis-trimethoxy)organosilane (DAPy) precursor by using Pluronic P123 as structure directing template via sol-gel co-condensation method. The hydrolysis reaction of DAPy precursor and tetraethyl orthosilacate (TEOS) with a DAPy content of about 20 mol% to TEOS were incorporated into the mesopore walls of the mesoporous organosilica hybrid nanoparticles (DAPy@MSA NPs). Low-angle XRD and FT-IR, N2 adsorption-desorption analysis, SEM, TEM, and TG analysis were used to characterize the synthesized DAPy@MSA NPs. The DAPy@MSA NPs exhibit an order mesoporous structure with a high surface area, mesopore size and pore volume of approximately ∼465 m2/g, 4.4 nm and 0.48 cm3/g, respectively. The pyridyl groups integrated DAPy@MSA NPs showed the selective adsorption of Cu2+ ions from the aqueous medium by metal-ligand complex coordination of Cu2+ ions with the integrated pyridyl groups and the pendant hydroxyl (-OH) functional groups present into the mesopore walls of the DAPy@MSA NPs. In the presence of other competitive metal ions (Cr2+, Cd2+, Ni2+, Zn2+, and Fe2+), the DAPy@MSA NPs showed relatively high adsorption of Cu2+ ions (276 mg/g) from aqueous solution as compared to the other competitive metal ions at the same concentration (100 mg/L) of initial metal ion solution.

Facile synthesis of HPW@MOF-199 embedded in SBA-15 functionalized with -COOH groups as a steady catalyst for the esterification reaction

In this work, we successfully synthesized a novel composite (HPW@MOF-199/SBA-15C, PMS-15C) in which MOF-199 encapsulated HPW catalyst (named HPW@MOF-199) was confined in SBA-15C, which is the carboxy-functionalized SBA-15. Physicochemical properties of the composites PMS-15C were systemically characterized by N2 adsorption–desorption isotherms, wide-angle and low-angle XRD, XPS, FT-IR, SEM, and TEM. The results exhibited that HPW@MOF-199 had been successfully synthesized and embedded into the SBA-15C pores by COOH on the surface of SBA-15C. Meanwhile, the composites PMS-15C exhibited high activity and excellent reuse properties in the esterification reaction of acetic acid and ethanol, and no evidence of aggregation, leaching, or inactivation of HPW@MOF-199 during repeated use. The good dispersion of HPW within the MOF-199 cage and the interaction between HPW@MOF-199 and SBA-15C may be responsible for the good catalytic activity as well as the high stability of PMS-15C.

Multi-functional Behaviour of Eu2O3 Embedded 3D Mesoporous Silica Template KIT-6

Rare-earth (RE) oxide embedded ordered mesoporous silica have been successfully prepared via a solution impregnation method. The structure and physical property of the nanocomposites (NCs) were studied by low-angle X-ray diffraction, Transmission Electron Microscopy (TEM), Photoluminescence (PL) and magnetic measurement. The NCs exhibited the room temperature transition emission due to the presence of Eu3+ ions. Also the NC system showed a room temperature weak ferromagnetism due to the large oxygen vacancy present in the system. Photoluminescence, magnetic property and large surface area, make these NCs ideal multi-functional materials, which will have potential applications in the field of bio-medicine and drug-delivery. These kinds of nanocomposites are promising candidates for fabrication of various environment friendly smart devices.

FP.02 Mutation in KBTBD13 causes stiffening of thin filaments in skeletal muscle

Nemaline myopathy is caused by mutations in genes encoding thin filament proteins. Nemaline myopathy-type 6 (NEM6) is caused by mutations in <i>KBTBD13</i>. NEM6 patients display muscle weakness and slow kinetics of muscle relaxation. Whether KBTBD13 plays a role in thin filament structure/function, and whether such role can explain the NEM6 phenotype, is incompletely understood. Therefore, we developed a KBTBD13R408C–knockin (KI) mouse model. In line with the patients' phenotype, KI mice exhibit nemaline rods and slow relaxation kinetics. We used low-angle x-ray diffraction to study whether structural changes in the myofilaments can explain the contractile phenotype of KI mice. Intact soleus and extensor digitorum longus muscles (EDL) were dissected from wt and KI mice. Low angle x-ray diffraction experiments were conducted at the BioCAT beamline, Argonne National Laboratories. Muscles were mounted between a force transducer and a fixed hook, exposed to the x-ray beam during relaxed and maximal tetanic conditions. Images were recorded with 15ms acquisition time using a Pilatus 3xM1 detector set at 1.26 meter distance from the muscle. Results show that in relaxed soleus muscles the actin monomer spacing (27A) and myosin backbone spacing (28A) are shorter in KI compared to wt mice (2.7329 vs 2.7343nm; 2.8764nm vs 2.8797nm). Upon maximal tetanic activation, which was comparable between KI and wt muscles, the 27A spacing increased less in KI compared to wt muscles, indicating increased stiffness. Upon maximal tetanic activation, the 28A spacing increased in wt muscles, but this increase was comparable to that in KI mice. EDL muscle of KI mice showed no differences in actin monomer or myosin backbone spacings. Results indicate that thin filament stiffness, but not thick filament stiffness, is increased in KI mice, and that this increase is muscle-type specific. Sarcomere modeling shows that the increased stiffness of thin filaments contributes to slow relaxation kinetics.

Mesoporous hybrid organosilica for stabilizing Pd nanoparticles and aerobic alcohol oxidation through Pd hydride (Pd–H2) species

The hybrid periodic mesoporous organosilica (PMO) with APTES/DAR Schiff-based precursor 3-aminopropyltriethoxysilane (APTES) and 4,6-diacetylresorcinol (DAR) was synthesized in the presence of a structure-directing agent cetyltrimethylammonium bromide and tetraethoxysilane. Then, Pd (II) ions, as well as Pd nanoparticles, were incorporated inside the pore walls of the synthesized APTES/DAR-PMO. The PMO structure was characterized by HRTEM, FT-IR, TEM, FE-SEM, BET, SEM-EDX, low angle XRD, HADAF-mapping, TGA, and atomic absorption spectroscopy (AAS). Subsequently, the as-fabricated green heterogeneous nanocatalysts (Pd-NPs@APTES/DAR-PMO) was used as effective and sustainable catalysts for the aerobic oxidation of benzylic alcohols into their corresponding aldehydes in pure water A high Pd-NPs@APTES/DAR-PMO-catalyzed conversion level of the primary and secondary alcohols was demonstrated. Furthermore, the environmentally friendly catalyst showed outstanding stability, so that readily separated by centrifugation and reused for seven consecutive cyclic terms with good retention of high catalytic activities.

Ultrasonic assisted enhanced catalytic effect of perovskite to promote depolymerization of lignin

The search for renewable energy sources to replace fossil fuel has made lignin a promising carbon-containing resource. In this paper, LaNiO3 perovskite catalyst supported by mesoporous carrier with specific pore structure was prepared by the pore filling of MCM-41 with citrate complex precursors of nickel and lanthanum. Then the catalysts applied to maize straw lignin depolymerization. The results of low-angle XRD, N2 adsorption-desorption, IR spectroscopy and SEM confirmed that the catalyst has been successfully manufactured. Based on the yield of phenolic monomer, low molecular weight lignin derived bio-oil and high molecular weight lignin derived bio-oil as standard, the catalyst showed best catalytic effect when the reaction temperature was 250 °C, the reaction time was 6 h, the ratio of lignin to catalyst mass was 5: 1 and with ultrasonic assist. The yield of phenolic monomer was 11.46 wt% and that of bio-oil was 68.0 wt%. In general, this method is an excellent embodiment of the principle of Lignin-first as well as an excellent strategy for the production of value-added phenolics and high-quality bio-oils from lignin. It plays an important role in promoting the high value utilization of lignin in the future.

Block Copolymer and Cellulose Templated Mesoporous TiO2-SiO2 Nanocomposite as Superior Photocatalyst

A dual soft-templating method was developed to produce highly crystalline and mesoporous TiO2-SiO2 nanocomposites. Pluronic F127 as the structure-directing agent and pure cellulose as the surface area modifier were used as the templating media. While Pluronic F127 served as the sacrificing media for generating a mesoporous structure in an acidic pH, cellulose templating helped to increase the specific surface area without affecting the mesoporosity of the TiO2-SiO2 nanostructures. Calcination at elevated temperature removed all the organics and formed pure inorganic TiO2-SiO2 composites as revealed by TGA and FTIR analyses. An optimum amount of SiO2 insertion in the TiO2 matrix increased the thermal stability of the crystalline anatase phase. BET surface area measurement along with low angle XRD revealed the formation of a mesoporous structure in the composites. The photocatalytic activity was evaluated by the degradation of Rhodamine B, Methylene Blue, and 4-Nitrophenol as the model pollutants under solar light irradiation, where the superior photo-degradation activity of Pluronic F127/cellulose templated TiO2-SiO2 was observed compared to pure Pluronic templated composite and commercial Evonik P25 TiO2. The higher photocatalytic activity was achieved due to the higher thermal stability of the nanocrystalline anatase phase, the mesoporosity, and the higher specific surface area.

In-situ preparation of novel nanocomposites of PMMA and ordered mesoporous carbon (FDU-15)

Ordered mesoporous carbons have recently been in significant attention because of their unique hexagonal structure, tunable large pore volumes, high thermal stability, and high surface-to-volume ratio. In this research paper, for achieving the maximum compatibility between the FDU-15 and poly(methyl methacrylate) (PMMA), 3-aminopropyltriethoxysilane (KH-550) was used as a modifying and coupling agent to facilitate the bond formations between the mesoporous carbon and PMMA with the help of ultrasonic irradiation. Nanocomposite (NC) films were produced via the in-situ polymerization method aligned with various amounts of modified FDU-15. Sample characterizations were done by field-emission scanning electron microscopy (FE-SEM), low angle X-ray diffraction (LXRD), Fourier transform infrared spectroscopy, transmission electron microscopy (TEM), and thermogravimetric analysis (TGA). The LXRD pattern proved that the hexagonal mesoporous structure of FDU-15 was preserved in NCs, however, the intensities of reflexes and long range order were decreased. The PMMA-m-FDU 2 wt% showed the existence of some pores on its surface according to FE-SEM. The TEM images of the NC depicted well-ordered arrays of mesoporous carbon in the PMMA matrix perpendicular to the pore axis and confirmed the 2D structure of the mesopores. TGA data also confirmed that as the m-FDU-15 increases into the PMMA matrix, the higher thermal stability will achieve. Also, the Td will increase to the higher temperatures. The PMMA-m-FDU 2 wt% showed the highest thermal resistant among the other studied NCs.

Facile Synthesis of Mesoporous Silica at Room Temperature for CO2 Adsorption.

Although mesoporous silica materials have been widely investigated for many applications, most silica materials are made by calcination processes. We successfully developed a convenient method to synthesize mesoporous materials at room temperature. Although the silica materials made by the two different methods, which are the calcination process and the room-temperature process, have similar specific surface areas, the silica materials produced with the room-temperature process have a significantly larger pore volume. This larger pore volume has the potential to attach to functional groups that can be applied to various industrial fields such as CO2 adsorption. This mesoporous silica with a larger pore volume was analyzed by TEM, FT-IR, low angle X-ray diffraction, N2-adsorption analysis, and CO2 adsorption experiments in comparison with the mesoporous silica synthesized with the traditional calcination method.

Restraining deactivation of β-zeolite by modifying with MgAl2O4 spinel in gas-phase glycerol dehydration

MgAl2O4 dispersed on HBEA zeolite with different spinel contents were successfully synthesized and their glycerol dehydration performances were presented. The different solids were characterized by XRD, infrared (IR) and Raman spectroscopy, N2 physisorption, SEM-FEG, acidity by TPD-NH3 and DRIFTS-pyridine adsorption. It was not possible to observe the spinel phase in the diffractograms due to its high dispersion, while the reflections of the HBEA were evidenced in the different samples. The Raman and infrared spectra suggested the presence of stretches concerning the MgAl2O4 spinel. N2 isotherms and low-angle XRD indicated that the pore structure and textural properties were altered after impregnation, but the micro-mesoporosity of zeolite was maintained. The HBEA morphology did not undergo significant changes by modification with spinel and the metals are evenly distributed according to SEM and EDS spectral mapping. The addition of spinel on zeolite caused a change in the acidic properties of HBEA related to the type, number and strength of the sites according to the TPD profiles and the DRIFTS spectra. The 2% of MgAl2O4 on HBEA catalyst exhibited the best catalytic performance due to the effects of its acidic and textural properties, reaching 60% of glycerol conversion, 66% of acrolein selectivity in 6 h and 16% of coke deposited in 10 h, restricting deactivation compared to pure zeolite. The reaction pathway for the different products formed depending on the type of acid site were detailed in the proposed mechanism and correlated with electrostatic potential maps as well as the reactions for coke formation were described according to compounds identified by GC-MS after coke extraction.

Dihydropyrano quinoline derivatives functionalized nanoporous silica as novel fluorescence sensor for Fe3+ in aqueous solutions(aq)

A novel nanoporous silica-based fluorescence sensor with high selectivity and sensitivity was successfully prepared via grafting of 3-isocyanatopropyltriethoxysilane and dihydropyrano [3, 2-c] quinoline derivatives (DPQ) onto the pore walls of mesoporous silica. The attachment of fluorophore groups onto the surface of the SBA-15 was approved via TGA and FT‐IR spectroscopy. TGA analysis indicates a large weight loss about 49%, which is attributed to the binding of a large number of organic groups on the pores surface, which functional groups appeared in the FT-IR spectra. Structural characterization techniques have proved the type IV for N2 adsorption-desorption isotherm, which revealed the preservation of the mesoporous structure. Also, low-angle XRD, FESEM and TEM analyses demonstrate the formation of ordered and well-defined 2D hexagonal mesoporous structure (space group p6mm). Whereas, Fe3+ ions caused discernible fluorescence quenching of the fluorescence sensor, the other cations used did not significantly changed fluorescence emission of SBA-Si-DPQ. The fluorescence quenching of the sensor is attributed to the paramagnetic properties of Fe3+ ions that appear by complex formation between the urea group of the probe and Fe3+ ions. It is noteworthy that, the excitation at 310 nm caused an emission with a maximum at 478 nm wavelength. By the increasing concentration of the analytes, the emission intensity was decreased dramatically and good linearity observed between analytes concentrations and the fluorescence intensity quenching of the sensor. The measured detection limits for Fe3+ ions was 2.0 × 10−6 M.

Annealing temperature effect on structural and optoelectronic properties of γ-In2Se3 thin films towards highly stable photodetector applications

Metal chalcogenide-based photodetectors have been studied extensively in recent years. However, the dark current, detective spectral ranges, responsivities, and response time are still unsatisfactory. Also, the major challenge for photodetector material is the deposition of large-scale material, a high-quality film with high reliability and low variability. In this work, we have synthesized Indium selenide (γ-In2Se3) thin films using the RF magnetron sputtering technique. We have thoroughly investigated the effect of annealing temperature on structural, optical, morphological, and photo-sensing properties of the synthesized thin films. Low angle XRD confirms the formation of hexagonal γ-In2Se3 films. The crystallite size increases from 56 nm to 64 nm with an increase in annealing temperature. Raman spectroscopy and XPS techniques confirm the γ phase of indium selenide. FE-SEM analysis revealed that the synthesized films are compact and uniform. Also, they are free from holes and cracks, which is necessary for semiconductor applications. The agglomeration of particles is observed with an increase in annealing temperature. The EDS spectra revealed that synthesized γ-In2Se3 films have ideal stoichiometry with In:Se ratio of 2:3. The UV–visible spectroscopy analysis showed a slight decrease in bandgap from 2.0 eV to 1.93 eV with an increase in annealing temperature. Other optical properties, such as absorption coefficient (α), extinction coefficient (k), the real and imaginary part of dielectric constant, optical conductivity, etc., of synthesized γ-In2Se3 films critically depend on the annealing temperature. Finally, the synthesized γ-In2Se3 thin films were used to fabricate photodetectors on ITO-coated interdigital electrodes. All γ-In2Se3 photodetector shows good stability and repeatability under dark and illumination conditions. The rise and decay time decrease with increase in annealing temperature. Photodetector with γ-In2Se3 thin film annealed at 300 °C exhibited excellent photoresponsivity (1.12 mA/ W) and stable photoswitching behavior. A fast rise (0.22 s) and decay time (2.85 s) were observed for the prepared photodetector. Our work demonstrates that γ-In2Se3 photodetector can be a promising material for photodetection applications.

In-situ synthesis of metal-organic framework embedded in ordered mesoporous silica functionalized with carboxyl groups for 4-nitrophenol to 4-aminophenol

Herein, the –COOH functionalized ordered mesoporous silica (OMS-C) was successfully synthesized using 3-phosphonopropionic acid as a functionalized reagent via one-pot co-condensation method. Then Cu2+ ions were adsorbed by the –COOH groups present on the OMS surface. Finally, the composite material (MOF-199@OMS-C) functionalized by Metal-Organic Framework (MOF-199) was in-situ prepared through the Cu2+ ions adsorbed by the OMS-C. The experimental results of N2 adsorption–desorption, low-angle XRD, and TEM showed that MOF-199@OMS-C composites possessed an ordered 2D hexagonal mesoporous structure, high specific surface area and the formation of MOF-199 in the pore of OMS-C. Moreover, FT-IR, Raman, XPS, and TG analysis demonstrated the carboxylation on the surface of OMS, successful synthesis, and immobilization of MOF-199 within the pores of OMS-C through the –COOH of OMS, as well as the interaction between OMS-C and MOF-199. The MOF-199@OMS-C composites exhibited good catalytic activity in the reduction reaction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP). The apparent kinetic constant of the reduction reaction of 4-NP was 0.26 min−1 under the optimum reaction condition. The MOF-199@OMS-C composites prevented the loss and structural damage of MOF-199, and its catalytic activity even remained stable after 4 cycles. In addition, the kinetic curves of reduction reaction of 4-NPs were consistent with first-order kinetics.

Efficient separation of methanol/dimethyl carbonate mixtures by UiO-66 MOF incorporated chitosan mixed-matrix membrane

Pervaporation shows great potential in separation of organic-organic mixtures that are widely involved in chemical and petrochemical industries, while the separation performance of polymeric membranes is undesirable for practical application. In this work, we incorporated UiO-66 (ZrCl4) metal-organic frameworks (MOFs) into chitosan (CS) membrane to separate methanol-dimethyl carbonate (DMC) mixtures. ZrOCl2·8H2O or ZrCl4 was selected as metal precursor to synthesize UiO-66, which aimed to investigate the structural defect of UiO-66 for the separation performance of mixed matrix membranes (MMMs). BET, 1H NMR and low-angle XRD characterizations indicated that UiO-66 (ZrCl4) with appropriate pore size is more suitable for preferentially permeate methanol over DMC. IR, dielectric relaxation and DSC characterizations combined with molecular simulations revealed the ideal interfacial morphology of UiO-66/CS MMMs was owing to the favorable molecular interactions including hydrogen bond interaction and van der Waals interaction. Pervaporation separation of methanol-DMC mixtures demonstrated that UiO-66 (ZrCl4) nanofillers can simultaneously enhance the permeation flux and separation factor of CS membrane. The optimized 10 wt% UiO-66 (ZrCl4)/CS MMM exhibited total flux and methanol/DMC separation factor of 355 g/m2h and 337 for 10 wt% methanol-DMC mixtures at 50 °C, which were 3.4-fold and 25-fold higher than that of the pure CS membrane, respectively, and outperformed the state-of-the-arts polymer-based membranes.

High-temperature lamellar of an extremely anti-symmetrical surfactant, barium ethyl(n-octyl)phosphate, in D2O: A small angle neutron scattering study

The lamellar structure of an extremely anti-symmetric bi-tail-type surfactant “barium ethyl (n-octyl)phosphate Ba (EOP)2” in D2O was investigated by the SANS method. The SANS intensity spectra were analyzed, based on a one-dimensional paracrystal model with uniaxial randomly oriented stacks. The results provided the lamellar model in which the ethyl and n-octyl chains are closely packed in a tail-to-tail manner which alternately combines the short and long n-alkyl chains. The closely-packed lamella was ascribed to the coordination effect of Ba2+ to the two PO4− groups of the EOP surfactants, as a result of comparison with the x-ray low angle diffraction consequence of “a loosely packed lamellar model” of Li (EOP) (already reported by Hirata et al. [1]).

Catalytic performance of Co, Fe on MCM-41 synthesized from illite waste for gasification of torrefied cassava rhizome

The catalytic gasification of torrefied cassava rhizome (TCR) with metals (Co, Fe) on MCM-41 was studied throughout this work. The focus of this research is to synthesize, evaluate and analyze the performance of ordered mesoporous MCM-41 employing illite clay waste as silica and aluminum sources under hydrothermal pressure condition using cetyltrimethylammonium bromide as structure template. The characterization of catalysts was carried out by low angle X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscopy (TEM), and N2 physisorption isotherm which indicated the formation of well-ordered MCM-41 mesoporous materials, high surface area (952 m2/g) and corresponds to a type IV isotherm of hysteresis loop, respectively. Co and Fe were deposited on synthesized MCM-41 surface by impregnation method. The catalytic performance was tested in an ex-situ gasification process at 700 °C. The 5Co/MCM-41 catalyst significantly increased the carbon conversion from 68.63% to 77.30% while using 5Fe/MCM-41 catalyst yielded the highest H2/CO ratio of 0.66, hydrogen conversion of 26.80% and gas heating value of 10.72 MJ/kg. The results indicated that the illite waste may be converted to high-value zeolite material while TCR is a potential greener fuel feedstock for gasification. This novel method to synthesize the MCM-41 from illite clay waste utilized doping of cobalt and iron metal catalyst to increase the efficiency of gasification of TCR.

Influence of Isovalent ‘W’ Substitutions on the Structure and Electrical Properties of La2Mo2O9 Electrolyte for Intermediate-Temperature Solid Oxide Fuel Cells

Lanthanum molybdenum oxide (La2Mo2O9, LAMOX)-based ion conductors have been used as potential electrolytes for solid oxide fuel cells. The parent compound La2Mo2O9 undergoes a structural phase transition from monoclinic (P21) to cubic (P213) at 580 °C, with an enhancement in oxide ion conductivity. The cubic phase is of interest because it is beneficial for oxide ion conduction. In search of alternative candidates with a similar structure that might have a stable cubic phase at lower temperatures, we have studied the variations of the crystal structure and ionic conductivity for 25, 50, 62.5 and 75 mol% W substitutions at the Mo site using high-temperature X-ray diffraction, dilatometry, and impedance spectroscopy. Highly dense ceramic samples have been synthesized by solid-state reaction in a two-step sintering process. Low-angle X-ray diffraction and Rietveld refinement confirm the stabilization of the cubic phase for all compounds in the entire temperature range considered. The substitutions of W at the Mo site produce a decrement in the lattice parameter. The thermal expansion coefficients in the high-temperature range of the W-substituted ceramics, as determined by dilatometry, are much higher than that of the unmodified sample. The impedance spectra have been modeled using a modified genetic algorithm within 300–600 °C. A distribution function of the relaxation times is obtained, and the contributions of ohmic drop, grains and grain boundaries to the conductivity have been identified. Overall, our investigation provides information about cationic substitution and insights into the understanding of oxide ion conductivity in LAMOX-based compounds for developing solid oxide fuel cells.

Cu(II) Schiff base complex functionalized mesoporous silica nanoparticles as an efficient catalyst for the synthesis of questiomycin A and photo-Fenton-like rhodamine B degradation

Lychee-like Mesoporous Silica Nanoparticles (LMSN) were synthesized and functionalized with 3-Aminopropyltrimethoxysilane (3-APTMS) and a novel binuclear Copper complex. The synthesized materials were characterized by UV-DRS, Fourier transform infrared spectroscopy (FTIR), Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray Analysis (EDAX) analysis. The High Resolution Transmission Electron Microscopy (HR-TEM) analysis gives view on retention of structural order after functionalization. Thermogravimetric Analysis (TGA), low angle X-ray diffraction (XRD) and BET-BJH analyses confirmed the presence of schiff base complex moieties inside the pore architecture. Electron Spin Resonance (ESR) analysis provide evidence for the presence of paramagnetic copper and ICP-OES studies details the metal loading. The potential of synthesized material as an enzyme-mimetic catalyst for the synthesis of questiomycin A and Rhodamine B degradation agent was analysed in this work. The catalyst material served best with good yields and reusability.

Spontaneous chiral self-assembly of CdSe@CdS nanorods

Spontaneous chiral self-assembly of CdSe@CdS nanorods

Effect of NH3 Alkalization and MgO Promotion on the Performance of Ni/SBA-15 Catalyst in Combined Steam and Carbon Dioxide Reforming of Methane

In this work, 31.4 wt.% Ni/SBA-15 (Ni/SBA-15) nonpromoted and alkalized with ammonia solution and by MgO promoter catalysts were prepared and used for combined steam and CO2 reforming of CH4 (bireforming). Effect of concentration of ammonia solution (NH3(aq)) (10–25 vol.%) and Mg content (3–12 wt.%) on the properties of the Ni/SBA-15 catalysts was investigated by low-angle and powder X-ray diffraction (XRD), N2-BET isothermal adsorption, SEM, TEM, EDS mapping, H2-TPR, and CO2-TPD methods. The performance of the catalysts in bireforming was assessed in the temperature range of 550–800°C. The enhancement of dispersion of NiO particles, reducibility, and basicity of alkalized Ni/SBA-15 catalysts were responsible for improving the catalytic performance of this catalyst. The results revealed that the Ni/SBA-15 treated with 15-25% NH3(aq) solution and promoted with 3-9% Mg exhibited high activity for CH4 conversion. Meanwhile, Ni6Mg/SBA-15 showed the highest CO2 conversion. Among tested catalysts, Ni/SBA-15-20NH3 and Ni9Mg/SBA-15 samples had an almost equal activity with a CH4 conversion of nearly 97% and a CO2 conversion of about 84% at 700°C thanks to its moderate affinity with both CO2 and CH4. However, the H2/CO ratio of the product mixture remained at 2.02 on the Ni/SBA-15-20NH3 catalyst and almost 1 on the Ni9Mg/SBA-15 sample. These results might be related to the fact that the alkalization of the Ni/SBA-15 catalyst by NH3(aq) solution had an advantage over using MgO because side reactions were unlikely to occur.