Channels Of SBA-15 Research Articles

Efficient Catalytic Oxidation of Ethylene at 0 °C on an in Situ Carbon Modified Pt Catalyst Supported on SBA-15.

The design of efficient catalysts for catalytic ethylene (C2H4) oxidation is of crucial importance for extending the shelf life of fruits and vegetables. Herein, a carbon modified SBA-15 supported Pt catalyst (Pt/CSBA-15) was prepared in situ by a facile solid phase grinding-infiltration-inert atmosphere calcination method. Characterization results reveal that in the Pt/CSBA-15 catalysts thin carbon layers are successfully formed in the hexagonal pores of SBA-15. Additionally, Pt particles are well dispersed in the channels of SBA-15, and Pt/CSBA-15 has a smaller Pt particle size than the catalyst without carbon modification (i.e., Pt/SBA-15). O2 is more feasibly adsorbed and activated on small-sized Pt particles, and in situ formed carbon species enhance the hydrophobicity of catalysts. As a result, both 3Pt/CSBA-15 and 5Pt/CSBA-15 are able to maintain 100% conversion of 50 ppm of C2H4 for more than 7 h at 0 °C. 3Pt/CSBA-15 even achieves 81.5% C2H4 conversion and 71.6% CO2 yield after 20 h, exhibiting much more prominent catalytic performances than 3Pt/SBA-15. DFT calculations and in situ FTIR measurements confirm that small-sized Pt particles possess strong O2 affinity to promote O2 adsorption, and in situ formed hydrophobic carbon layers efficiently suppress competitive H2O adsorption. Such a unique one-step catalyst preparation method for regulating the size of metal particles and the hydrophobicity of catalysts can be perfectly utilized to develop simple and efficient hydrophobic catalysts applied in low-temperature oxidation of C2H4.

Palladium covalently anchored imidazolium functionalized SBA-15: An efficient recoverable heterogeneous catalyst for the hydrocarboxylation of styrene

An efficient Pd/Imi-SBA-15 heterogeneous catalyst was synthesized by a covalent anchoring strategy for the hydrocarboxylation of styrene. Various characterization methods (e.g. FT-IR, XRD, 29Si MAS NMR, BET and ICP) demonstrated that PdCl2 was successfully anchored in the channels of SBA-15, and the mesoporous structure of the SBA-15 substrate was maintained throughout the grafting process. The Pd/Imi-SBA-15 catalyst was proven to be highly efficacious, persistent and reusable in the catalytic system for the hydrocarboxylation of styrene due to an outstanding synergistic effect between H+/Cl−-Pd. The presence of H+/Cl− could promote the formation of the H–Pd complex, and accelerate the reaction process. The DFT calculations indicated that a higher orbital energy level of the adsorbed styrene in the [HPdLCl] complex (L = PPh3) existed than that of free styrene, realizing that the [HPdLCl] complex promoted the electron activity of styrene and thus facilitated the styrene carbonylation process. Furthermore, PPh3 was more likely to induce the transformation of styrene into branched products. In the end, a practicable catalytic mechanism of Pd/Imi-SBA-15 for hydrocarboxylation was proposed.

Synthesis, thermal evolution and magnetic investigations of SBA-15 silica functionalized with anchored iron phosphonate molecules.

In the current work, we report on the synthesizing of a series of novel nanocomposite materials obtained by functionalizing the SBA-15 silica matrix with anchored iron phosphonate molecules and the following thermal treatment. The obtained results reveal the formation of a unique amorphic layer of Fe-based compounds on the surface of silica walls of SBA-15 channels as a result of the organic groups' decomposition after moderate thermal treatment. Due to their unique structure, represented in an active Fe-containing amorphous coating spread over a large surface area, these materials are of great interest for their potential applications in fields such as catalysis, adsorption, and non-linear optics. The obtained materials remain amorphous, preserving the SBA-15 mesoporous structure up to temperatures of approximately 800 °C, after which the partial melting of the silica backbone is observed with the simultaneous formation of nanocrystals inside the newly-formed glassy mass. All obtained materials were characterized using such techniques as thermogravimetry, transmission and scanning electron microscopy combined with energy dispersive x-ray spectroscopy mapping, Raman spectroscopy, N2sorption analysis, x-ray diffraction, x-ray photoelectron spectroscopy, Mössbauer spectroscopy, and SQUID measurements.

One-pot synthesis of iron oxide - Gamma irradiated chitosan modified SBA-15 mesoporous silica for effective methylene blue dye removal

The development of adsorption technology and the processing of radiation have both been influenced by chitosan adsorbent (γ-chitosan), a raw material with unique features. The goal of the current work was to improve the synthesis of Fe-SBA-15 utilizing chitosan that has undergone gamma radiation (Fe-γ–CS–SBA-15) in order to investigate the removal of methylene blue dye in a single hydrothermal procedure. High-resolution transmission electron microscopy (HRTEM), High angle annular dark field scanning transmission electron microscopy (HAADF-STEM), small- and wide-angle X-ray powder diffraction (XRD), Fourier transform-infrared spectroscopy (FT-IR) and Energydispersive X-ray spectroscopy (EDS) were used to characterize γ–CS–SBA-15 that had been exposed to Fe. By using N2-physisorption (BET, BJH), the structure of Fe-γ–CS–SBA-15 was investigated. The study parameters also included the effect of solution pH, adsorbent dose and contact time on the methylene blue adsorption. The elimination efficiency of the methylene blue dye was compiled using a UV-VIS spectrophotometer. The results of the characterization show that the Fe-γ–CS–SBA-15 has a substantial pore volume of 504 m2 g−1 and a surface area of 0.88 cm3 g−1. Furthermore, the maximum adsorption capacity (Qmax) of the methylene blue is 176.70 mg/g. The γ-CS can make SBA-15 operate better. It proves that the distribution of Fe and chitosan (the C and N components) in SBA-15 channels is uniform.

Metal-metal oxide synergistic catalysis: Pt nanoparticles anchored on mono-layer dispersed ZrO2 in SBA-15 for high efficiency selective hydrogenation

It is generally believed that noble metal catalysts exhibited higher activity for selective hydrogenation, while metal oxides were almost inactive. Here, we report metal-metal oxide synergistic catalysis for high efficiency selective hydrogenation by a hybrid nano-structure Pt/@-ZrO2/SBA-15 catalyst, which was fabricated by anchored Pt nanoparticles on the mono-layer dispersed ZrO2 film layer coated in SBA-15 support via a photochemical route. This Pt/@-ZrO2/SBA-15 catalyst exhibited remarkable catalytic activity in the selective hydrogenation of CO bond, NO2, and CC bond. For the selective hydrogenation of benzaldehyde, conversion >99.9% was achieved with >99% selectivity, and the turnover frequency (TOF) can be achieved up to 4822 h−1, which was much higher than that of the atomically dispersed Pd1/TiO2-EG catalyst (1002 h−1) reported in the literature, no decay in the activity was observed by several cycles. Combined the experimental and characterization results, proved that the ZrO2 was dispersed in a mono-layer in the channel of SBA-15, and the results showed that an appropriate loading of ZrO2 in this catalyst could maximize the advantage of this hybrid nano-structure to achieve the best catalytic activity. The superior activity of Pt/@-ZrO2/SBA-15 was attributed to the synergistic catalysis, strong interface electronic effect, and the unique properties of the special hybrid nano-structure. This work demonstrated synergistic catalysis of metal Pt nanoparticles and monolayer dispersion ZrO2 for high efficiency selective hydrogenation.

Novel Antitumor Agents Based on Fluorescent Benzofurazan Derivatives and Mesoporous Silica

Two novel fluorescent mesoporous silica-based hybrid materials were obtained through the covalent grafting of [4-hydrazinyl-7-nitrobenz-[2,1,3-d]-oxadiazole (NBDH) and N1-(7-nitrobenzo[c][1,2,5]-oxadiazol-4-yl) benzene-1,2-diamine (NBD-PD), respectively, inside the channels of mesoporous silica SBA-15. The presence of fluorescent organic compounds (nitrobenzofurazan derivatives) was confirmed by infrared spectroscopy (IR), X-ray photoelectron spectroscopy (XPS), thermal analysis (TG), and fluorescence spectroscopy. The nitrogen physisorption analysis showed that the nitrobenzofurazan derivatives were distributed uniformly on the internal surface of SBA-15, the immobilization process having a negligible effect on the structure of the support. Their antioxidant activity was studied by measuring the ability to reduce free radicals DPPH (free radical scavenging activity), in order to formulate potential applications of the materials obtained. Cytotoxicity of the newly synthesized materials, SBA-NBDH and SBA-NBD-PD, was evaluated on human B16 melanoma cells. The morphology of these cells, internalization and localization of the investigated materials in melanoma and fibroblast cells were examined through fluorescence imaging. The viability of B16 (3D) spheroids after treatment with SBA-NBDH and SBA-NBD-PD was evaluated using MTS assay. The results showed that both materials induced a selective antiproliferative effect, reducing to various degrees the viability of melanoma cells. The observed effect was enhanced with increasing concentration. SBA-NBD-PD exhibited a higher antitumor effect compared to SBA-NBDH starting with a concentration of 125 µg/mL. In both cases, a significantly more pronounced antiproliferative effect on tumor cells compared to normal cells was observed. The viability of B16 spheroids dropped by 40% after treatment with SBA-NBDH and SBA-NBD-PD at 500 µg/mL concentration, indicating a clear cytotoxic effect of the tested compounds. These results suggest that both newly synthesized biomaterials could be promising antitumor agents for applications in cancer therapy.

Phosphonic acid tagged carbon quantum dots encapsulated in SBA-15 as a novel catalyst for the preparation of N-heterocycles with pyrazolo, barbituric acid and indole moieties

Herein, we have presented a new insight for the synthesis of a hybrid heterogeneous catalyst. For this purpose, phosphonic acid tagged carbon quantum dots of CQDs-N(CH2PO3H2)2 encapsulated and assembled in channels of SBA-15 using a post-modification strategy. The mesoporous catalyst of functionalized carbon quantum dots (CQDs) was characterized by several techniques. CQDs-N(CH2PO3H2)2/SBA-15 as an excellent catalyst was applied for the preparation of novel pyrazolo[4′,3′:5,6]pyrido[2,3-d]pyrimidine derivatives by using pyrazole, barbituric acid and indole moieties at 100 °C under the solvent-free condition. The present work shows that a significant increase in the catalytic activity can be achieved by a rational design of mesoporous SBA-15 modified with CQDs for the synthesis of biological active candidates. The synthesized compounds did not convert to their corresponding pyridines via an anomeric-based oxidation mechanism.

Facile regulation of Lewis sites and 3D mesoporous channel within Ce-SBA-15 for catalytic ozonation of clofibric acid

The traditional 2D channel of SBA-15 was not favor for the mass transfer and Lewis sites exposures, which restrained its application in catalytic ozonation. Herein, we proposed a facile hydrothermal method for simultaneously regulating pore structure (from 2D to 3D channel) and introducing Ce-based Lewis sites within Ce-SBA-15 with urea (named as Ce-SBA-U) as pH-regulator. pH ascension induced by urea during hydrothermal and phase transition process could weaken the electrostatic interaction between inorganic silicate and surfactant molecules as well as slowed down the hydrolysis and condensation rates of silane, which facilitated the doping of cerium, enlargement of mesoporous sizes and formation of 3D mesoporous channel. Mesoporous sizes of Ce-SBA-U was manipulated by urea dosage and could be enlarged to more than 20 nm, which favored for the mass transfer of ozone and its further activation on Ce(III)-based Lewis sites. The redox cycle of Ce(III)/Ce(IV) could donate electron for surface bonded O3 for the generation of hydroxyl radicals (•OH), superoxide radical (O2•−) and singlet oxygen (1O2). Benefiting from the above features, Ce-SBA-U/O3 process achieved 98.1% clofibric acid (CA) removal and 35.4% TOC removal, which were far beyond those of sole ozonation and Ce-SBA-15/O3 processes. The involved mechanism together with the degradation pathways were exploited by comparative characterizations and experiments. This work could broaden the application of SBA-15 in catalytic ozonation.

Restrictive Regulation of Ionic Liquid Quaternary Ammonium Salt in SBA-15 Pore Channel for Efficient Carbon Dioxide Conversion.

Herein, the synthesis of a new type of catalyst, SBA-M (Schiff complex of different metal types grafted on SBA-15) based on a quaternization reaction, is described. Various amounts of ionic liquid were grafted into the pore channels of SBA-15 using the post-grafting method, which allowed the ionic liquid to be grafted into the pore channels restrictively. Notably, over six cycles, SBA-Mn (0.2) has been shown to maintain its catalytic activity and stability. In addition, a reaction mechanism for the cycloaddition of CO2 with epoxides based on density-functional theory is proposed. The cycloaddition reaction of CO2 and epoxides is an efficient way of carbon fixation. It is demonstrated that the metal coordinated with the oxygen atom of the epoxides and that a halogen attacked the carbon of epoxides. Moreover, theoretical calculations and synthesis strategy provide a new approach for CO2 conversion.

Adsorption application of tetraethylenepentamine (TEPA) modified SBA-15@MIL-101(Cr) in carbon capture and storage (CCS)

To design a better carbon capture material, a SBA-15@MIL-101(Cr) composite is prepared by an in situ synthesis method, and its adsorption performance is enhanced by TEPA modification. The SBA-15 with well-ordered mesopores acted as a carrier, which regulated the growth of MIL-101(Cr) crystals. The silicon hydroxyl group in SBA-15 stably binds to TEPA in the form of hydrogen bond, and the Lewis acid site (CUS) in MIL-101(Cr) makes it bind to TEPA in coordination bond. The unique pore cage structure of MIL-101(Cr) and the basic site provided by TEPA make the material contain both physical and chemical adsorption forces in the process of adsorption of CO2 molecules. The good thermal stability of SBA-15 improves the thermal stability of MIL-101(Cr) and TEPA in the SBA-15 channel. Compared with the original MIL-101(Cr), the composite and modified materials showed higher CO2 absorption capacity at 298K and 100 kPa. By fitting the Langmuir equation and Freundlich equation, it can be found that the adsorption behavior of the materials after TEPA loading has the non-uniformity of surface binding. The adsorption behavior is a typical exothermic process, so the adsorption capacity of the material is inversely proportional to the temperature. Compared with other similar materials, the materials designed in this work have good CO2 adsorption energy per unit area, and also have good reusability. Therefore, this study opens a new way for the design of graded porous amine-modified MOF-based materials with advanced gas adsorption properties.

Exchange bias of ordered α-Fe2O3 nanowires: A first-order reversal curve analysis

Ordered α-Fe2O3 nanowires with different gap sizes and diameters were fabricated using SBA-15 as template through varying calcination temperature. The composition, microstructure and morphology of the samples were characterized by XRD, TEM and N2 adsorption–desorption isotherms. The results showed that the α-Fe2O3 replicated the pore channels of SBA-15. The nanowire diameter and wire spacing were controllably changed at different calcination temperatures. ZFC-FC, hysteresis lines and First-order reversal curve (FORC) of the samples were tested at 10 K, 50 K, 100 K, 200 K and 300 K. Exchange bias (EB) was observed under low-temperature field cooling conditions due to the increase of spin disorder on the surface of small size α-Fe2O3 which was freezen into a spin-glass-like phase at low temperature. The influence of the domain states and interactions on EB of α-Fe2O3 were investigated using FORC. The mixed domain states were observed for small size samples at low temperatures. The excitation of EB at low temperatures was proven to be influenced by magnetic interactions.

Characterization and release kinetics model of thymol from starch-based nanocomposite film into food simulator.

To improve the performance of potato starch films and solve the problems of high volatility and low stability of thymol (Thy), thymol was loaded into the channel of SBA-15 to prepare Thy-SBA-15, and the Thy-SBA-15/potato starch film was prepared. The results showed thymol was successfully loaded into the pores of SBA-15. The addition of Thy-SBA-15 enhanced the tensile strength of potato starch film (3.93 Mpa), reduced the water vapor permeability (1.56 × 10-12 g·d-1 m-1 Pa-1 , WVP) and moisture absorption (80.97%, MA), which enhanced the barrier properties of the films. Thy-SBA-15 had good compatibility with potato starch films. Notably, the thymol released from Thy-SBA-15/potato starch film was initially explosive, and then continuous, which showed this film could effectively slow down the release rate of thymol and prolong the fresh-keeping period of food. The Korsmeyer-Peppas model (R2 > .96) had the best fit for the release curve of thymol. PRACTICAL APPLICATIONS: This work offers a new method for the preparation of potato starch sustained-release antibacterial film, and provides a theoretical basis and technical support for the development of intelligent packaging.

Selected acid and basic functionalized ordered mesoporous materials as solid catalysts for transesterification of canola oil: A comparative study

This study investigates the preparation and application of mesoporous silica-supported basic and acidic catalysts in transesterification. Mesoporous silicas of SBA-15 and MCF type were prepared and modified by post-synthesis with organic moieties (amine and sulfonic). The obtained supports and catalysts were characterized by N2 adsorption, IR spectroscopy, MAS NMR, SEM, and TEM techniques. The results show that several active groups attached to the SBA-15 and MCF silica channels do not lead to the collapsing of the characteristic open structure of the mesoporous sieves. The investigated catalysts exhibit high activity and selectivity in the transesterification of canola oil. The SBA-15-phenyl-SO3H one shows the highest conversion (84.6%) after 6 h (at 150 °C), which is comparable to the activity of H2SO4. The selectivity towards fatty acid methyl esters was noted at the level of 60.6% (after 6 h of reaction).

The Application of Modified SBA-15 as a Chemosensor

: The Santa Barbara Amorphous (SBA-15), with a large surface area covered with abundant Si-OH active groups on the walls of its pores, can be modified with various organic compounds to build organic-inorganic hybrid materials, which can be used as a catalyst in organic reactions, drug delivery systems, nano sorbent due to its high capacity for removing heavy metals in waste water and as chemosensors for ions. Tunable and straight channels of SBA-15 facilitate the entrance and diffusion of ions through the channels. This paper presents a review of the past five years of literature covering the application of SBA-15 as an ions chemosensor in the liquid and gaseous media.

Copper nanoparticles decorated N-doped mesoporous carbon with bimodal pores for selective gas separation and energy storage applications

• Mesoporous N & Cu doped carbon materials with enhanced physico-chemical features. • Materials display redox, conducting, basic, adsorption and porous characteristics. • N/Cu doped carons show ordered structure with a bimodal pores size distribution. • High gas adsorption capacity and selectivity in a mixture of CO 2 /H 2 and CO 2 /CH 4. • High values for supercapacitance with good cyclic ability and capacitance retention. We demonstrate a synthesis of copper nanoparticles decorated over nitrogen-doped mesoporous carbon with different N and Cu contents which exhibit conducting, redox, basic, adsorption, and excellent textural properties. These materials are prepared through a nanotemplating approach by simultaneously encapsulating sucrose, guanidine hydrochloride, and Cu(NO 3 ) 2 into the porous channels of mesoporous SBA-15 at a low carbonization temperature of 600 °C. The prepared materials exhibit an ordered mesoporous carbon framework with bimodal pores, decorated with nitrogen and Cu functionalities on the surface of the pores and in the wall structure. The presence of nitrogen functionalities in the porous carbon matrix not only helps to reduce the Cu ions but also stabilizes the nanoparticles and offers redox sites, which are beneficial for adsorption and electrochemical applications. The optimized sample exhibits the highest adsorption capacity of different gases such as CO 2 – 22.5 mmol/g at 273 K, H 2 −13.5 mmol/g at 77 K at 30 bar and CH 4 − 5 mmol/g at 298 K and 50 bar. We also demonstrate that the prepared material shows a high selectivity of adsorption towards CO 2 in a mixture of CO 2 /H 2 and CO 2 /CH 4 and it also registers a high supercapacitance of 209 F g −1 at a current density of 1 A g −1 with excellent cyclic stability.

Synthesis and hydrogen isomerization performance of ordered mesoporous nanosheet SAPO-11 molecular sieves

In this study, ordered mesoporous nanosheet SAPO-11 molecular sieves were synthesized using uncalcined SBA-15 molecular sieves as a Si source. The effects of different Si sources on the structure and properties of SAPO-11 molecular sieves were examined, and their growth mechanism was elucidated. An electrostatically polarized region was formed between a P123 template (triblock copolymer) contained in uncalcined SBA-15 and two-dimensional channels of SBA-15 molecular sieves. When AlO2− and PO2+ species diffused into this region, its electrostatic polarization promoted the preferential growth of SAPO-11 molecular sieves along the c-axis, which contained a large number of exposed catalytically active sites with acidic properties. During the isomerization of long-chain alkanes, the synthesized sieves exhibited high isomerization activity and selectivity. When the conversion rate of n-dodecane reached 87.96%, the yield of i-dodecane was 68.08%, and the yield of multi-branched i-dodecane was 31.65%.

Highly dispersed tungsten-based quantum dots confined in porous channel induced by ionic liquid with remarkable desulfurization behavior

Developing highly dispersed species has been regarded as an effective approach to achieve high catalytic performance. In this work, tungsten-containing precursor were control confined in porous channel of SBA-15. Profiting from the ionic liquid, quantum dots (such as WO3 QDs) in SBA-15 with highly dispersion can be obtained after thermal treatment. This prepared tungsten-based QDs confined SBA-15 materials can deliver excellent catalytic performance for oxidation desulfurization, in which 100 % DBT can be removed in 1 h. The oxidation desulfurization reaction mechanism is also explored and main active specie is determined to be ·OH. This strategy provides an accessible pathway for preparation of other catalysts with highly dispersed species.

Silicotungstic acid-derived WO3 composited with ZrO2 supported on SBA-15 as a highly efficient mesoporous solid acid catalyst for the alkenylation of p-xylene with phenylacetylene

Highly dispersed silicotungstic acid-derived WO3 composited with ZrO2 supported on SBA-15 (WZ/SBA-15) as an ordered mesoporous solid acid catalyst was prepared via a facile incipient wetness impregnation (IWI) method that active ingredients, ZrO2 and WO3, were impregnated into the channels of SBA-15 simultaneously with a subsequent calcination process. The relationship between catalyst nature and performance was explored by high resolution transmission electron microscopy (HRTEM), high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM), FT-IR, X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), N2 adsorption-desorption, NH3 temperature-programmed desorption (NH3-TPD), and FT-IR of pyridine adsorption (Py-IR) characterization techniques. The catalytic performance of W12Z15/SBA-15 is not only greater than that of single component solid acid catalysts, WO3/SBA-15 and ZrO2/SBA-15, but also W12/Z15/SBA-15 prepared by impregnating active ingredients, ZrO2 and WO3, into SBA-15 in sequence. The outstanding performance of W12Z15/SBA-15 is derived from the strong interaction between ZrO2 and WO3, which results in more acid sites, and relatively high specific surface area, large pore volume, and ordered mesoporous structure of SBA-15. The characterization and reaction results clearly demonstrate that the synergy of ZrO2 and WO3 has a clear boost for the alkenylation. The optimized W12Z15/SBA-15-500 achieves a 99.4% conversion of phenylacetylene and a 92.3% selectivity of main product α-arylstyrene for the alkenylation of p-xylene with phenylacetylene, with very low level of oligomers producing at the same time. Moreover, W12Z15/SBA-15-500 shows excellent catalytic stability and regeneration. Therefore, W12Z15/SBA-15-500 is a promising solid acid catalyst for the alkenylation.

Effects of spatially confined nickel nanoparticles in surface-pretreated hydrophobic SBA-15 for dry reforming of CH4 with CO2

The efficient methods to preserve original smaller nickel nanoparticles (NP) with its even size distribution of ∼5 nm on a highly ordered mesoporous SBA-15 (NP/SBA-15) were investigated for a high temperature (800 °C) dry reforming of methane with CO2 (DRM). The suppressed thermal aggregation with less coke deposition and higher catalytic activity were observed by the confined nickel nanoparticles spatially in the mesoporous SBA-15 channels. Especially, two-step surface-pretreated SBA-15 with acetic anhydride followed by successive H2O treatment showed a higher dispersion of organics-stabilized nickel nanoparticles, which were preferentially deposited in the ordered mesoporous inner SBA-15 channels with its insignificant aggregation. On the optimal NP(10)/SBA-15 with 10 wt%Ni possessing the characteristics of the hydrophobic SBA-15 inner surfaces, as-prepared nickel nanoparticles were selectively and homogeneously distributed in the inner mesoporous SBA-15 channels with its small depositions on the outer SBA-15 surfaces. The spatial confinement effects were realized due to the less mobility of the smaller nickel nanoparticles by keeping its original particle sizes even after a long-term DRM reaction at 800 °C for 120 h. The phenomena were responsible for an enhanced catalytic stability by suppressing a severe sintering of nanoparticles and less coke formation even under a harsh DRM reaction condition.

Fabrication of mesoporous WO3-SBA-15 catalysts and enhanced photocatalytic degradation of harmful dyes

Mesoporous SBA-15 and x% WO3-SBA-15 (X = 2.7 %, 5.5 %, 8.3 % and 11.1 %) catalysts were synthesized by hydrothermal in-situ method. All the synthesized catalysts were subjected to different analytical techniques such as XRD, FT-IR, BET, XPS, FE-SEM, EDX, HR-TEM, DRS-UV and PL. The HR-TEM images showed that WO3 species were highly dispersed in the uniform pore channels of SBA-15. Photo decolorization activity of the bare and composite catalysts measured in the degradation of harmful dyes such as rhodamine B (RhB), methylene blue (MB) and crystal violet (CV) under UV, visible and solar light irradiations. Among the catalysts, 5.5 % WO3-SBA-15 exhibited the highest photocatalytic activity (81 %, 90 %, and 77 %) towards the degradation of RhB, MB and CV dyes under visible light irradiation. TOC and COD studies indicated that the three dyes chosen for the present study were all degraded to large extent. The trapping experiment confirmed that the major species responsible for the photocatalytic degradation of different dyes over 5.5 % WO3-SBA-15 catalysts were found to be h+ and O2−. The stability of the most active catalysts 5.5 % WO3-SBA-15, was determined by the recyclability test. A suitable mechanism was proposed based on experimental evidence.