Formation Of Mesoporous Silica Research Articles

In-depth study of factors affecting the formation of MCM-41-type mesoporous silica nanoparticles

Mesoporous silica nanoparticles (MSN), especially MCM-41 type, have been broadly studied and used in different applications such as catalysis, nanomedicine and environmental science. One of the most advantageous properties of these materials is their easy and tunable synthesis. Nevertheless, in spite of the efforts made by researchers in the last decades, there is still no complete understanding of the mechanism and factors affecting the formation of MCM-41 type MSN, and some parameters are disregarded in the reported synthesis protocols. Considering that the fine-tuning of the parameters affecting nanoparticle synthesis is the basis for obtaining well-defined nanodevices with advanced complex functionalities, an in-depth study of the factors affecting the formation of MCM-41 type MSN is carried out in this work. We analyzed the first stages of MSN formation, namely the silica-surfactant templating and nanoparticle nucleation and growth, and found that hydrolysis and condensation rates play a central role in nanoparticle formation. Furthermore, we found that some disregarded parameters in the MCM-41 type synthesis, such as the stirring strength or the surfactant addition rate, modulate nucleation and growth, influencing the hydrolysis and condensation rates. Finally, we studied the aging and the evolution of the MSN by analyzing the consolidation of the silica framework over time. Therefore, we further elucidate some points about the mechanism and factors affecting the formation of mesoporous silica, which brings us closer to obtaining reproducible, homogeneous and tailored-made MCM-41 type MSN.

Synthesis of mesoporous silica from geothermal water

Mesoporous silica was successfully synthesized for the first time using geothermal water from the Onuma Geothermal Power Plant, Akita Prefecture, Japan. Cetyltrimethylammonium bromide (CTAB) was used as an organic template for the synthesis. CTAB with a concentration of 2.4 × 10–4 mol/L was reacted for 30 min with geothermal water at a temperature of 90 °C, which had a total silicic acid concentration of 475 mg/L (SiO2), at pH 7.0, pH 8.2 (raw water) and pH 9.0. By calcination of the resulting precipitate at 550 °C, mesoporous silica with a pore size of about 2.8 nm and a specific surface area of > 800 m2/g was formed. The total silicic acid concentration in the solution after formation of the mesoporous precipitates was reduced to < 280 mg/L, indicating efficient recovery of supersaturated silicic acid from geothermal water. The monosilicic acid in geothermal water plays an important role in the formation of mesoporous silica. Production of mesoporous silica by our method will contribute not only to prevention of silica scale formation in the piping systems of geothermal power plants but also to its use as an industrial resource.

Enhanced specificity of bimetallic ions via mesoporous confinement for phosphopeptides in human saliva

Phosphopeptides were of great significance in disease diagnosis and monitoring its dynamic changes. In this article, we proposed a more efficient method to synthesize a kind of bimetallic mesoporous silica nanomaterials (Fe3O4@mSiO2-PO3-Ti4+/Zr4+) and applied it to the analysis of phosphopeptides in human saliva samples based on IMAC technology. The chelation group was introduced into mesopores at the same time as the formation of mesoporous silica which significantly reduced the synthesis procedure and improved the synthesis efficiency. The as-prepared materials showed great sensitivity, selectivity and size-exclusion performance for phosphopeptides in standard β-casein digests. More importantly, the materials identified 85 phosphopeptides in disease saliva samples which provided a candidate choice in future clinical examination.

Effect of Alcohol Chain Length on Formation of Cetyltrimethylammonium Bromide‐templated Mesoporous Silica Layer on Gold Nanorods

This is the first study that elucidates the effect of alcohol alkyl chain length on the formation of mesoporous silica (mSiO2) layers on cetyltrimethylammonium bromide (CTAB)‐stabilized gold nanorods (CGNRs). The growth tendencies of the mSiO2 layers on the CGNRs (CGNR@mSiO2) in various alcohol solvents differed quite substantially from those observed for previously reported spherical silica particles. The formation of the mSiO2 layer was closely related to the interaction between the CTAB bilayer and alcohol.

Formation of boron – silica based mesoporous and studies of its adsorption ability for curcuminoids

The development aims of mesoporous silica formation in pharmaceutical fields were its uses as a drug delivery vehicle and in separation. It is possible because of the large particle surface area, the presence of pores, and the possibility to modify functional groups in the mesoporous materials. In this study, the formation of silica-based mesoporous and boron-silica-based mesoporous materials was carried out by sol-gel techniques and modification of functional groups was carried out by the co-condensation method. Mesoporous material characterization was carried out using scanning electron microscopy (SEM), transmission electron microscopy (TEM), and Fourier transform infrared (FTIR). Adsorption ability of curcuminoid onto the mesoporous was carried out through isotherm adsorption study approaches using adsorption models including Langmuir, Freundlich, and Temkin model. The results of the isotherm adsorption study showed that the Freundlich model is the best model for isotherm adsorption with an r2 value of 0.997.

Core-shell nanoparticles for medical applications: effects of surfactant concentration on the characteristics and magnetic properties of magnetite-silica nanoparticles

Objective(s): The use of cationic surface-active agents (surfactant) in the synthesis of nanoparticles, with formation of micelle, can act as a template for the formation of meso-porous silica. Changes in the concentration of surfactants can affect the structures and properties of the resulting nanoparticles.Materials and Methods: Magnetite nanoparticles were prepared as cores using the coprecipitation method. Silica shells were formed on the prepared cores using sol-gel through the single-step process. During synthesis, cetrimonium bromide (CTAB) was used as a surfactant at low (0.1 g), medium (1 g), and high concentrations (7 g), and the effects on the properties of the nanoparticles were investigated. The core-shell nanoparticles were analyzed using X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). In addition, the surface porosities of the nanoparticles were evaluated using the BET and BJH methods. The vibrating sample magnetometer (VSM) was also employed to assess the magnetic characteristics of the synthesized samples. Results: The results of XRD indicated that the nanoparticles were composed of magnetite and silica, while the SEM and TEM images confirmed the presence of uniform spherical particles with a core-shell structure. According to the results of the VSM tests, all nanoparticles showed super-paramagnetic behaviors. Moreover, the increased concentration of CTAB led to an increment in saturation magnetization (Ms), size, and volume of the surface pores, while the specific surface area of the nanoparticles decreased. Conclusion: According to the results, the properties of the silica shell could be adjusted in terms of pore characteristics and magnetic behavior by changing the concentration of the surfactant.

Porous Silica Nanomaterial Derived from Organic Waste Rice Husk as Highly Potential Drug Delivery Material

Rice became the main product of agriculture in agrarian countries including Indonesia. Rice husk is a waste of rice as one of the largest silica producers. Silica from rice husks can be used as a source of silica in the manufacture of sodium silicate as an alternative to the formation of mesoporous silica at a low price. In this research, the characterization of mesoporous silica nanoparticle (MSN) MCM-41 from rice husk (rice husk) with sol-gel method followed by hydrothermal treatment. Silica extraction was performed by titrating sodium silica using HCl method until the gel was formed. The mesoporous synthesis was performed with the addition of CTAB. The titration is then carried out using a solution of acetic acid. XRD shows silica with an amorphous structure. The FTIR results show that extraction silica and MSN MCM-41 contain pure silica displayed with Si-O-Si functional groups in the sample. The SEM results show MSN MCM-41 images such as a coral-like structure of agglomerated silica and the higher temperature hydrothermal treatment then it would be the more large size of particles. The material has a hexagonal pore structure such as a honeycomb as characteristic of MCM-41 with a pore size of 2.535 nm which includes mesoporous material. The result of nitrogen adsorption-desorption isotherms shows lower hydrothermal temperature will increase the specific surface area and decrease average pore size, where the best result with surface area value is 825.365 m2/gr and average pore size is 6.10426 nm obtained from process hydrothermal at 85°C.

Molecular mechanisms of mesoporous silica formation from colloid solution: Ripening-reactions arrest hollow network structures.

The agglomeration of silica nanoparticles in aqueous solution is investigated from molecular simulations. Mimicking destabilization of colloidal solutions by full removal of protective moieties or surface charge, association of SiO2/Si(OH)4 core/shell particles leads to rapid proton transfer reactions that account for local silanole → silica ripening reactions. Yet, such virtually barrier-less binding is only observed within a limited contact zone. Agglomeration hence leads to the formation of oligomers of nanoparticles, whilst full merging into a compact precipitate is hampered by the need for extended structural reorganisation. Implementing sufficiently fast supply from colloidal solution, our simulations show the development of silica networks comprised of covalently bound, yet not fully merged nanoparticles. Within the oligomerized nanoparticle network, coordination numbers range from 2 to 5 –which is far below closest packing. Our simulations hence rationalize the formation of covalently bound network structures hosting extended pores. The resulting interfaces to the solvent show water immobilization only for the immediate contact layers, whilst the inner pores exhibit solvent mobility akin to bulk water.

Synthesis and characterization of hierarchical porous clay heterostructure from Al, Fe -pillared nano-bentonite using microwave and ultrasonic techniques

Abstract The present research is focused on the textural, structural and surface properties of Al, Fe and Si hierarchical porous nano-bentonite heterostructure (PBH) derivated from Al, Fe pillared nano-bentonite (Al, Fe-PILB). The application of Al, Fe-PILB as a precursor to prepare porous clay minimized the use of cationic surfactant, water consumption, synthetic time and organic wastes. Furthermore, the incorporation of Al and Fe species from Al, Fe-PILB in the silica framework was performed in one step reaction compared to the conventional method required the continuous control for hydrolysis and condensation in the synthesize of PBH. Besides using Al, Fe-PILB as a precursor, the ultrasonic and microwave techniques were firstly assisted to the synthesis of PBH for opening bentonite layers with breaking pillars resulted in the increasing basal spacing and improving mesoporous silica formation in interlayer space of Al, Fe-PILB in little synthetic time. The LPSD, XRD, UV–Vis spectra, N2 adsorption-desorption, FESEM-EDS, TEM, and FTIR analyses allowed for a better understanding of PBH behaviors under different synthetic conditions. The results showed that the use of pillared clays in the conventional method did not lead to the formation of PBH due to the strong interaction between the Al, Fe species and the clay layers. The synergism effect of ultrasonic waves and microwave irradiation reduced the structural damage of nano-bentonite and improved BET surface area (867 m2/g), micropore and mesopore volume (0.62 cm3/g) compared to the only application of ultrasonic or microwave techniques. These properties make PBH as an attractive candidate for catalysis and adsorption applications.

Could Mesophases Play a Role in the Nucleation and Polymorph Selection of Zeolites?

Zeolites and mesoporous silicas are porous materials with important applications in catalysis, gas storage, and separation. Zeolite crystals form in the presence of cationic surfactants that act as structure directing agents (SDAs). The way SDAs control the nucleation and polymorphs selection in zeolites is not fully understood. The formation of mesoporous silica is templated by liquid crystalline mesophases that result from frustrated attraction between silicates and long-chain SDAs. Experiments indicate that surfactants C nH2 n+1(CH3)3N+ with n > 6 yield mesoporous silicas, and the one with n = 6 produces a zeolite. This suggests that the driving force toward mesophase formation is also present for small organocations, but is overcome by the ability of silica to wrap a crystal lattice around them. Here we use molecular dynamics simulations to investigate whether the existence of metastable mesophases can play a role in the nucleation and polymorph selection of zeolitic crystals. As a proof of concept, we investigate the phase behavior of simple mesogenic mixtures of SDAs and a network former T that favors tetracoordinated crystals. We represent the network-former T by Stillinger-Weber models of water and silicon, in lieu of silica, because a computationally efficient silica potential that would allow for the spontaneous nucleation of zeolites in molecular dynamics simulations is not yet available. The mixtures of T and SDA produce a rich phase diagram that encompasses the sII clathrate and at least six zeolites, including sigma-2 (SGT). We find that the nucleation of SGT is not assisted by a mesophase. The nucleation of the other five zeolites of this study, however, is facilitated by the existence of metastable mesophases that decrease the nucleation barriers and direct the selection of the crystal polymorph. Together with the experimental support for mesophases in mixtures of silicates and SDAs, our results for model systems suggest that metastable mesophases could play a prominent role in promoting the nucleation and polymorph selection of some zeolites.

Formation of block-copolymer-templated mesoporous silica

In situ attenuated total reflectance Fourier transform infrared spectroscopy is used to monitor the chemical evolution of the mesoporous silica SBA-15 from hydrolysis of the silica precursor to final silica condensation after the particle formation. Two silica precursors, tetraethyl orthosilicate (TEOS) or sodium metasilicate (SMS) were used, and the effects of additive (heptane and NH4F) concentrations were studied. Five formation stages are identified when TEOS is used as the precursor. The fourth stage correlates with the appearance and evolution of diffraction peaks recorded using in situ small angle X-ray diffraction. Details of the formed silica matrix are observed, e.g. the ratio between six-fold cyclic silica rings and linear bonding increases with the NH4F concentration. The TEOS hydrolysis time is independent of the NH4F concentration for small amounts of heptane, but is affected by the size of the emulsion droplets when the heptane amount increases. Polymerization and condensation rates of both silica precursors are affected by the salt concentration. Materials synthesized using SMS form significantly faster compared to TEOS-materials due to the pre-hydrolysis of the precursor. The study provides detailed insights into how the composition of the synthesis solution affects the chemical evolution and micellar aggregation during formation of mesoporous silica.

Mesoporous silica formation on hydroxyapatite nanoparticles

The additive effect of TEOS and CTAB on the HAp crystal growth and HAp/silica hybrid shape was investigated. The mesoporous silica formation on the HAp nanoparticles was successfully achieved, and the SBET and RBJH values were changed with the feed Ca/P ratio. The HAp/silica hybrids exhibited the higher SBET values with the mesopores. It was suggested that the silica phase specifically interacted with the a-plane of HAp and subsequently the HAp along with the c-axis direction to be anisotropic hybrid shapes.

Template-free sol–gel synthesis of high surface area mesoporous silica based catalysts for esterification of di-carboxylic acids

High surface area mesoporous silica based catalysts have been prepared by a simple hydrolysis/sol–gel process without using any organic template and hydrothermal treatment. A controlled hydrolysis of ethyl silicate-40, an industrial bulk chemical, as a silica precursor, resulted in the formation of very high surface area (719 m 2 /g) mesoporous (pore size 67 Å and pore volume 1.19 cc/g) silica. The formation of mesoporous silica has been correlated with the polymeric nature of the ethyl silicate-40 silica precursor which on hydrolysis and further condensation forms long chain silica species which hinders the formation of a close condensed structure thus creating larger pores resulting in the formation of high surface mesoporous silica. Ethyl silicate-40 was used further for preparing a solid acid catalyst by supporting molybdenum oxide nanoparticles on mesoporous silica by a simple hydrolysis sol–gel synthesis procedure. The catalysts showed very high acidity as determined by NH 3 -TPD with the presence of Lewis as well as Brønsted acidity. These catalysts showed very high catalytic activity for esterification; a typical acid catalyzed organic transformation of various mono- and di-carboxylic acids with a range of alcohols. The in situ formed silicomolybdic acid heteropoly-anion species during the catalytic reactions were found to be catalytically active species for these reactions. Ethyl silicate-40, an industrial bulk silica precursor, has shown a good potential for its use as a silica precursor for the preparation of mesoporous silica based heterogeneous catalysts on a larger scale at a lower cost. Very high surface area (719 m 2 /g) mesoporous (pore size 67 Å and pore volume 1.19 cc/g) silica has been prepared by a simple sol–gel process using ethyl silicate-40 as a novel silca precursor without using any organic template and hydrothermal treatment. Molybdena supported on this high surface area silica has yielded a solid acid catalyst efficient for esterification of di-carboxylic acids with a range of alcohols.

Incorporation of anti-inflammatory agent into mesoporous silica

The unique properties of macroporous, mesoporous, and microporous systems, including their ability to accommodate molecules of different sizes inside their pores and to act as drug delivery systems, have been the object of extensive studies. In this work, mesoporous silica with hexagonal structure was obtained by template synthesis via the sol–gel process. The resulting material was used as support to accommodate the anti-inflammatory agent indomethacin. The alkaline route was used to prepare the mesoporous silica; cetyltrimethylammonium bromide was employed as porogenic agent. The silica particles were functionalized with 3-aminopropyltriethoxysilane alkoxide (APTES) by the sol–gel post-synthesis method. Indomethacin was incorporated into the silica functionalized with APTES and into non-functionalized silica. The resulting systems were characterized by x-ray diffraction (XRD), specific area, infrared spectroscopy, and thermal analyses (TGA). XRD attested to formation of mesoporous silica with hexagonal structure. This structure remained after silica functionalization with APTES and incorporation of indomethacin. Typical infrared spectroscopy vibrations and organic material decomposition during TGA confirmed silica functionalization and drug incorporation. The specific surface area and pore volume of the functionalized material incorporated with indomethacin decreased as compared with the specific surface area and pore volume of the non-functionalized silica containing no drug, suggesting both the functionalizing agent and the drug were present in the silica. Cytotoxicity tests conducted on normal fibroblasts (GM0479A) cells attested that the silica matrix containing indomethacin was less toxic than the free drug.

Kinetic Influence of Siliceous Reactions on Structure Formation of Mesoporous Silica Formed via the Co-Structure Directing Agent Route

We investigate the mechanism responsible for the formation of mesoporous silica formed with the so-called costructure directing agent (CSDA) route. The synthesis relies on the interaction between silica source (tetraethylorthosilicate), cationic surfactant (C18H37N+(CH3)2(CH2)3N+(CH3)3Br2), and CSDA (carboxyethylsilanetriol), which results in a material functionalized with carboxylic groups. Depending on the concentration of HCl in the synthesis, the structure is defined by Fm3m (at high pH) and by Fd3m (at low pH), with a gradual transition in the intermediate pH range. Here, we aim at finding the origin for the structural change triggered by pH and investigate the effects of the hydrolysis of the silica source on the overall kinetics of the synthesis. A fast process results in Fm3m, regardless of pH, and a slow process results in Fd3m. The hydrolysis step is the important structural control parameter. We studied the cross-linking of silica and CSDA using 29Si NMR. The cross-linking is similar for th...

Synthesis of magnetic mesoporous nanocomposites: A promising candidate for diagnostic and therapeutic biomedical applications

In the present research, iron oxide nanoparticles were synthesized through the hydrothermal method, and the influence of processing parameters such as pH of the initial coprecipitation reaction, time and temperature of hydrothermal treatment was studied. The magnetic iron oxide nanoparticles were coated with a negatively charged, thin layer of silica. The product is then coated with a layer of mesoporous silica. As a result of the electrostatic attraction between the cationic CTAB and the primary silica coating, the formation of mesoporous silica would be mainly localized on the surface of nanoparticles. Calcination was performed in an argon atmosphere tube furnace at 550 °C, through which CTAB was decomposed and eliminated thoroughly from the structure, thereby leaving the oriented pore structure behind. The effects of synthesis parameters such as the ethanol/water volume ratio, the amount of catalyst needed for the sol–gel reaction, and the molar ratio of TEOS/CTAB on the synthesized nanocomposite were investigated. FESEM observations were used to define the morphology and approximate particle size of the product. The FTIR analysis confirmed the formation of Si–O–Fe bonds as a proof for the core/shell morphology of the nanocomposite particles. The nitrogen adsorption behavior through the BET method proved the presence of mesopores in the magnetic nanocomposite. The specific surface area of the nanocomposite varied with the amount of CTAB in the range of 212–295 m2/g. The magnetic mesoporous nanocomposite possessed a considerable magnetic saturation of 30 emu/g, while the final mean diameter of the nanoparticles was about 42 nm.

A general method for growing large area mesoporous silica thin films on flat substrates with perpendicular nanochannels.

Here we introduce a new synthetic approach to grow mesoporous silica thin films with vertical mesochannels on centimeter-sized substrates via an oil-induced co-assembly process. Adding an oil, i.e., decane, into a CTAB-EtOH-TEOS ammonia solution leads to thin-film formation of mesoporous silica of controlled thickness between 20 and 100 nm with vertical mesochannels on various surfaces. The vertical mesoporous channels were evidenced by grazing incidence small-angle X-ray scattering (GISAXS), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) characterizations. Decane played two roles: (a) as a pore expansion agent (up to 5.7 ± 0.5 nm) and (b) inducing vertically oriented hexagonal mesophases of micelle-silica composite. The production of periodic and vertical nanochannels is very robust, over many different substrate surfaces (from silicon to polystyrene), various silica precursors (TEOS, fumed silica, or zeolite seed), and many oils (decane, petroleum ether, or ethyl acetate). This wide robustness in the formation of vertical nanophases is attributed to a unique mechanism of confined synthesis of surfactant-silicate between two identical thin layers of oils on a substrate.

A facile approach for the tunable wormlike or ordered pore morphology of mesoporous silica: Effect of catalyst types and polyethylene glycol

Two different basic catalysts, NaOH and NH4OH, to the formation of mesoporous silica with completely different pore morphology at the same mole concentration with or without polyethylene glycol (PEG) were investigated. NaOH catalyzed system seemed to have a more ordered structure and larger particle size than NH4OH catalyzed system. The addition of PEG tended to promote the charge matching probability for silicate oligomers and micelles, which resulted in the more ordered pore morphology for NH4OH system. With increased ammonia concentrations, the pore morphology of disordered wormlike structure was transformed into ordered MCM-41 type mesoporous structure with particle dimension in a few tenths of nanometer to hundred nanometer. With the addition of PEG, at low ammonia concentration, the mesoporous pores became more orderly arranged as well. However, the effect of PEG on the pore and particle morphology of the NaOH catalyzed system was less evident than that of the NH4OH system. The catalyst types were also investigated at the same pH to contrast the significance of catalyst effect on the preparation of mesoporous silica, which was often neglected in the literature. NaOH catalyzed system still indicated a more ordered wormlike structure and slightly larger particle size than NH4OH catalyzed system. The XRD (X-ray diffraction) results and N2 adsorption–desorption isotherms were in agreement with the TEM (Transmission electron microscope) morphology. The significance of two different catalysts with the addition of PEG in tuning pore morphology was justified.

Synthesis of ordered mesoporous carbon doped with carbon nanotubes and a new strategy to use it as a support for Pt electrocatalysts

Our work pivots around modified mesoporous materials as supports for Pt electrocatalysts. Carbon nanotubes–ordered mesoporous carbon (CNTs–OMC) composite materials have been successfully fabricated through a hard template method. Firstly, carbon nanotubes–ordered mesoporous silica (CNTs–OMS) composites were prepared by using P123 as an organic template for directing the formation of mesoporous silica. Ordered mesoporous carbon doped with CNTs (designated as CNTs–OMC) has been successfully replicated from the above-synthesized CNTs–OMS template by using sucrose as a carbon precursor. We find that the addition of appropriate CNTs has no effect on the ordered mesoporous structure of carbon and can make the mesoporous structure more stable. The TEM images of the CNTs–OMC show highly ordered parallel channels and CNTs can be uniformly embedded in the ordered mesoporous carbon matrix. The OMC after doping shows a higher electrical conductivity of 26.4 S m−1 while that of the OMC (before doping) is only 4.3 S m−1, which is due to the nature of its graphitic framework as well as its lower interfacial resistance. Then the CNTs–OMC and OMCs were used as fuel cell catalyst supports for loading Pt nanoparticles prepared via a microwave synthesis process. The conductivity and plumbaginous degree of the CNTs–OMC composite are higher than those of OMC, which is beneficial for loading Pt nanoparticles. The Pt/CNTs–OMC catalyst has a higher electrochemical active surface area of 113.4 m2 g−1 than that of the Pt/OMC catalyst, which indicates that the addition of an appropriate amount of CNTs to OMC significantly improves the performance of Pt nanoparticles.

Synthesis of well-ordered SO42−/ZrO2-SiO2 materials in bi-acid system

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.