Rod-like SBA-15 Research Articles

Construction of multi-porous Ni-based monolithic catalyst by combining wood carbon and SBA-15 for strengthening CO2 methanation

Monolithic catalysts meet the needs of practical application compared with powder catalysts. In this work, we constructed a Ni-based monolithic catalyst (Ni/SAB-15/WWC) by in situ growth of rod-like mesoporous SBA-15 in the microchannels of wood carbon. The small Ni-based nanoparticles (∼5.3 nm) were uniformly dispersed into the mesoporous channels via a post-loading method. The monolithic Ni/SAB-15/WWC catalyst with a multilevel porous structure could provide a laminar gas flow on the surface of Ni active sites, increasing the low-temperature activity and high-temperature durability of CO2 methanation. The Ni/SAB-15/WWC with low Ni loading (∼2%) displayed superior CO2 methanation catalytic performance in terms of low-temperature activity and CH4 selectivity compared with the powder Ni/SAB-15 with high Ni loading (∼15 %). The combination of wood carbon and mesoporous materials is an innovative strategy for the design monolithic catalysts with low metal loading and excellent catalytic performance.

Direct air CO2 capture using coal fly ash derived SBA-15 supported polyethylenimine

Designing an amine modified silica derived from coal fly ash (CFA) towards direct air CO2 capture (DAC) provides an economic way to manage increasing atmospheric CO2 concentration utilizing solid wastes. In this work, rod-like SBA-15 (SBA-15-R) and wheat-like SBA-15 (SBA-15-W) with distinct pore lengths are synthesized from CFA by controlling the synthesis conditions and then modified by PEI via the wet impregnation method. Their CO2 adsorption behaviors under sub-ambient conditions are investigated to explore their feasibility under aggressive conditions. The adsorbents with various silica morphologies exhibit distinctive CO2 adsorption performance under ambient and sub-ambient conditions. At 35°C under dry conditions, the CO2 adsorption capacity increases with amine loading. The CO2 adsorption capacity (qe) of SBA-15-W-PEI with long channels reaches the highest qe of 1.92 mmol/g with 70 wt.% PEI loading due to a large amount of strong chemisorption sites. Under the sub-ambient conditions (-20°C, 400 ppm), SBA-15-R-PEI30 with short channels having weaker CO2 diffusion resistance exhibits promising CO2 uptake of 0.83 mmol/g. These findings indicate that the ultra-dilute CO2 adsorption at ambient temperature requires an adsorbent with large amounts of adsorption sites, whereas the adsorbents for cold temperature application should reconcile amine loading with CO2 diffusion resistance inside pores. The co-adsorption of H2O and CO2 significantly improves CO2 capacity from 0.83 mmol/g and 1.92 mmol/g to 1.81 mmol/g and 3.48 mmol/g for SBA-15-R-PEI30 (-20°C, 400 ppm) and SBA-15-W-PEI70 (35°C, 400 ppm), respectively. Furthermore, the CFA derived SBA-15-PEI shows good cyclic stability during five consecutive TSA cycles. Preparing the amine silica adsorbents from coal fly ash potentially reduces the adsorbent cost of DAC devices. Moreover, the systematic exploration of amine silica adsorbents at a wide range of temperatures guides the design of high-performance CO2 adsorbents employed under various climatic conditions.

RAFT polymerization of MMA in channels of different mesoporous materials

A series of mesoporous silica (MS) materials, including rod-like and spherical SBA-15, spherical MCM-41, and MCM-48, was successfully synthesized and modified by silane coupling agent γ-aminopropyltriethoxysilane. The modified MS was utilized as a microreactor for solution reversible addition–fragmentation transfer (RAFT) polymerization of methyl methacrylate (MMA) using xanthate as a chain transfer agent and azodiisobutyronitrile as an initiator. Notably, modified MS had a low specific surface area and pore volume while maintaining the original morphological structure. Given to the confinement effects, poly(methyl methacrylate) (PMMA) prepared from internal mesoporous channels had higher molecular weight and initial thermal decomposition temperature than those from conventional RAFT polymerization. Moreover, PMMA obtained from spherical SBA-15 and modified MCM-48 exhibited the highest molecular weight (Mn = 8.78 × 104 and Mn = 7.43 × 104, respectively). This work provided a novel approach in designing a polymer microstructure for a more comprehensive application, such as in drug release.Graphical abstract

Effect of glycerol and H3PO4 on the bioactivity and degradability of rod-like SBA-15 particles with active surface for bone tissue engineering applications

In the quest to increase the quality of life and life expectancy, there is a great demand to develop advanced medical devices capable of facing current health challenges. Santa Barbara Amorphous (SBA-15) mesoporous silica has been demonstrated to be a remarkable option for a variety of biomedical applications, from tissue engineering to drug delivery, due to its unique hierarchical porous structure. This work reports on the effect of using different ratios and concentrations of an acid mixture mediated by HCl/H 3 PO 4 that in combination with a glycerol-modified silane precursor favoured obtaining bioactive SBA-15 mesoporous silica rods. The surfactant was removed by solvent extraction which allowed to keep a substantial amount of silanol groups (SiOH) at the surface. All the evaluated samples showed homogeneous rod shape and particle size, as well as high bioactivity after being immersed for 14 days in simulated body fluid (SBF). Different structural arrangements of needle-type carbonate hydroxyapatite (HCA) crystals were produced from SBA-15 upon immersion in SBF. By scanning electron microscopy (SEM) characterization, it was observed that rod-shaped SBA-15 materials displayed higher degradability when the concentration of H 3 PO 4 was increased. An indirect cell viability assay with MC3T3-E1 osteoblast precursor cells was performed by incubating cells in cell culture medium exposed to SBA-15 particles for 1 and 4 days. The results obtained from the WST-8 assay and fluorescent staining showed no negative effect on cell viability, indicating a lack of cytotoxicity of the rod-like SBA-15 particles. • Solvent extraction allowed keeping a large amount of silanol groups at the surface. • Higher the concentration of H 3 PO 4 smaller the size of the SBA-15 rods. • PO 4 3− species and SiOH promoted the formation of carbonate hydroxyapatite crystals. • The use of H 3 PO 4 and glycerol facilitated the degradation process at body pH. • The species released from SBA-15 particles after 4 days boosted cell proliferation.

Effects of morphology and pore size of mesoporous silicas on the efficiency of an immobilized enzyme.

An investigation is performed into the efficiency of the Streptomyces griseus HUT 6037 enzyme immobilized in three different mesoporous silicas, namely mesoporous silica film, mesocellular foam, and rod-like SBA-15. It is shown that for all three supports, the pH value changes the surface charge and charge density and hence determines the maximum loading capacity of the enzyme. The products of the enzyme hydrolytic reaction are analyzed by 1H-NMR. The results show that among the three silica supports, the mesoporous silica film (with a channel length in the range of 60–100 nm) maximizes the accessibility of the immobilized enzyme. The loading capacity of the enzyme is up to 95% at pH 7 and the activity of the immobilized enzyme is maintained for more than 15 days when using a silica film support. The order of the activity of the enzyme immobilized in different mesoporous silica supports is: mesoporous silica film > mesocellular foam > rod-like SBA-15. Furthermore, the immobilized enzyme can be easily separated from the reaction solution via simple filtration or centrifugation methods and re-used for hydrolytic reaction as required.

Ni/Fibrous type SBA-15: Highly active and coke resistant catalyst for CO2 methanation

The rod-like SBA-15 was transformed into fibrous type SBA-15 (F-SBA-15). The Ni/F-SBA-15 was catalytically evaluated in CO2 methanation and compared with conventional Ni/SBA-15. A superior catalytic performance was shown by Ni/F-SBA-15 (CO2 conversion = 99.7%, and CH4 yield = 98.2%) than Ni/SBA-15 (CO2 conversion = 91.1%, and CH4 yield = 87.5%). This phenomenon was attributed to the favorable physicochemical properties of F-SBA-15 as evidenced by the characterization results. A higher homogeneity of finer Ni was embedded onto the F-SBA-15 support, subsequently strengthened the Ni interaction with F-SBA-15, and increased the amount of moderate basic sites. The in situ FTIR studies evidenced the CO2 methanation over both catalysts proceeded via CO2 dissociation pathway. Three intermediate species (linear carbonyl, unidentate, and bidentate carbonates) were detected for Ni/F-SBA-15, while only bidentate carbonates were detected for Ni/SBA-15, signifying excellent catalytic attributes of Ni/F-SBA-15. Additionally, Ni/F-SBA-15 demonstrated higher stability and coke resistance ability than Ni/SBA-15.

Comparison of spherical and rod-like morphologies of SBA-15 for enzyme immobilization

Mesoporous silica, namely SBA-15, has been used for enzyme immobilization to help improve thermal stability of the enzymes and, in some cases, increase the enzymatic activity. It has been shown that morphology of SBA-15 is one of the factors influencing kinetics of enzyme adsorption. We reported, here, the adsorption kinetics and peroxidase activity of cytochrome c (cytc) in spherical SBA-15 in comparison of three different rod-like (fibrous, fiber, and rope) SBA-15 samples. The experimental adsorption profile fitted much better to the pseudo-second order than the pseudo-first order model. The maximum loading capacity of cytc was 466, 423, 390, and 352 mg/g for fibrous, rope, fiber, and spherical SBA-15, respectively. The rate constant for cytc adsorption for spherical SBA-15 was 3 times slower than rope and fiber SBA-15, and 15 times slower than fibrous SBA-15. The activity of cytc after immobilization in SBA-15 samples depended on the amount of cytc loading. The cytc loading in all SBA-15 at lower than 10 µmol/g showed higher activity than in free cytc in solution. The maximum activity of immobilized cytc was found in spherical SBA-15 at cytc loading of 1.00 µmol/g (~ 7 times higher than in free cytc). Finally, the Fe(III) at the heme group of cytc/SBA-15 samples with high activity was examined to contain high-spin state. The investigation in this work could suggest useful information for the preparation of SBA-15 for enzyme immobilization to appropriate applications, such as drug delivery.

Synthesis of SBA-15 assembled with silicon nanoparticles with different morphologies for oxygen sensing

Abstract In this paper, our effort is focused on preparation and oxygen sensing of fluorescent silicon nanoparticles (Si NPs) assembled in three kinds of mesoporous SBA-15 with different morphologies, including spherical mesoporous SBA-15 (SPSBA-15), long rod-like mesoporous SBA-15 (LRSBA-15) and hexagonal prism-like mesoporous SBA-15 (HPSBA-15). The relationship of structure and sensing properties in mesoporous materials is studied. Small angle powder X-ray diffraction (SAXRD), Fourier transform infrared spectrometer (FT-IR), Brunauer-Emmett-Teller (BET), Discrete-Fourier-Transform (DFT) analyses and X-ray photoelectron spectroscopy (XPS) are used to characterize their structural properties. The obtained mesoporous SPSBA-15, LRSBA-15 and HPSBA-15 possess abundant Si–O–Si bands of the inorganic framework and high surface-volume ratios. Particularly, mesoporous HPSBA-15 materials exhibit the largest surface areas than other two mesoporous materials. Accordingly, the adding volume of Si NPs was 8 ml in mesoporous HPSBA-15. At the same time, the hybrid materials show the shortest response time of 2.2 s and recovery time of 11.2 s. This result can be attributed to the uniform and nearly parallel porous structure of the HPSBA-15 materials supporting with large surface areas and narrow pore size distributions. Therefore, the properties in oxygen sensing can be improved by using mesoporous SBA-15 materials with larger BET surface area.

Dendritic fibrous SBA-15 supported nickel (Ni/DFSBA-15): A sustainable catalyst for hydrogen production

In the present study, dendritic fibrous type SBA-15 (DFSBA-15) was successfully discovered for the first time by modulating the typical rod-like SBA-15. The synthesized DFSBA-15 was loaded with 5 wt% Ni, catalytically applied in dry reforming of methane (DRM), and catalytically compared with the conventional Ni/SBA-15. Characterization (XRD, BET, FTIR, TEM, SEM-EDX, CO2-TPD, and H2-TPR) results showed that Ni/DFSBA-15 consists of high basic sites, uniform Ni distribution, and easy reducible of NiO, resulting to the ameliorated catalytic activity, coking resistance and high catalytic stability with no indication of deactivation after 30 h time-on-stream for Ni/DFSBA-15. The superior activity of Ni/DFSBA-15 (XCO2 = 84.43%, XCH4 = 86.29%, YH2 = 64.94%, SH2 = 40.09% and rH2 = 6.64 mmol/g.s) might be ascribed to the open and flexible fibrous hierarchical of DFSBA-15 support, that rendered higher active sites accessibility and oxygen vacancy than that of SBA-15. The relatively inferior performance of Ni/SBA-15 (XCO2 = 77.12%, XCH4 = 78.02%, YH2 = 46.96%, SH2 = 33.26% and rH2 = 4.80 mmol/g.s) can be accounted on the one-end opening pores of pristine SBA-15 which are easily clogged by NiO nanoparticles, consequently, hindering reactant gaseous from accessing its active sites. The post reaction characterizations (XRD and TPO), confirmed the insignificant coke deposition and metal sintering for Ni/DFSBA-15. The promising physicochemical and catalytic properties possessed by unique DFSBA-15, acknowledged its feasibility in H2 production via DRM.

2D/3D amine functionalised sorbents containing graphene silica aerogel and mesoporous silica with improved CO2 sorption

This work investigates the performance of amine functionalised 2D/3D sorbents for CO2 capture. The 2D/3D structures were based on a combination of flake-like reduced graphene-silica oxide (G-Si) aerogel and rod-like mesoporous silica SBA-15. The G-Si aerogel formed mainly silica microporous structures which enveloped graphene sheets. The SBA-15 displayed the classical rod-like mesoporous features with high pore volume. The addition of G-Si aerogel to SBA-15 for the amine functionalised samples significantly reduced the combined total surface area and pore volume. Interestingly, the CO2 sorption capacity increased and peaked for samples containing G-Si aerogel/SBA-15 at 1:20 mass ratio (4.7 wt%), though declining thereafter. This counterintuitive effect of increasing CO2 sorption capacity but decreasing surface area and pore volume was attributed to the special morphological features of the 2D/3D sorbent assembly. At these optimal conditions, the flake-like G-Si aerogel was well intercalated with the rod-like SBA-15. As a result, the inter-particle space formed between the flake-like and rod-like assembly accommodated TEPA which facilitate the mass transfer and reaction between the amine groups and CO2. These special 2D/3D morphological features delivered high CO2 sorption capacity of 6.02 mmol g−1. The 2D/3D sorbents were also very stable under sorption and desorption cycles whilst heat of sorption were up to 22% lower than the analogue 3D SBA-15/TEPA sorbent.

Highly catalytic activity of Mn/SBA-15 catalysts for toluene combustion improved by adjusting the morphology of supports.

Rod-like, hexagonal and fiber-like SBA-15 mesoporous silicas were synthesized to support MnOx for toluene oxidation. This study showed that the morphology of the supports greatly influenced the catalytic activity in toluene oxidation. MnOx supported on rod-like SBA-15 (R-SBA-15) displayed the best catalytic activity and the conversion at 230°C reached more than 90%, which was higher than the other two catalysts. MnOx species consisted of coexisting MnO2 and Mn2O3 on the three kinds of SBA-15 samples. Large amounts of Mn2O3 species were formed on the surface and high oxygen mobility was obtained on MnOx supported on R-SBA-15, according to the H2 temperature programmed reduction (H2-TPR) and X-ray photoelectron spectroscopy (XPS) results. The Mn/R-SBA-15 catalyst with greater amounts of Mn2O3 species possessed a large amount of surface lattice oxygen, which accelerated the catalytic reaction rate. Therefore, the surface lattice oxygen and high oxygen mobility were critical factors on the catalytic activity of the Mn/R-SBA-15 catalyst.

Confinement effect of mesoporous silica reactors on electron transfer atom transfer radical polymerization of styrene

Controlled/living free radical polymerization in confined space is expected to produce new materials with predetermined structures and special properties. In this work, various morphologies of mesoporous silicas were synthesized and used as a nanoreactor for bulk activators regenerated by electron transfer atom transfer radical polymerization (ARGET ATRP) of styrene. The resulting mesoporous silica/polystyrene (MS/PS) nanocomposites and PS within the pore channels were characterized by scanning electron microscope, transmission electron microscope, nitrogen adsorption–desorption measurements, fourier transform infrared spectrometer, thermogravimetry analysis, gel permeation chromatography, differential scanning calorimetry, and proton nuclear magnetic resonance (1H-NMR) spectra. In comparison to conventional bulk ARGET ATRP of styrene (without MS), the pore channels of the MS show an evident confinement effect on bulk ARGET ATRP of styrene. The morphology, molecular weight and polydispersity, glass transition temperature (Tg), and spatial configuration of PS are strongly related to the morphology and internal pore channels of the MS. The bulk ARGET ATRP of styrene in 3D cubic bicontinuous structure MCM-48 shows a high potential for isospecific polymerization. The PS obtained in rod-like SBA-15 (2D), spherical SBA-15, and MCM-41 (1D) exhibit a higher molecular weight, polydispersity index and Tg. The PS obtained in 3D MCM-48 exhibits enhanced molecular weight along with decreased the polydispersity. Moreover, the morphologies of the polymers obtained in mesoporous silica are consistent with that of the corresponding mesoporous silicas.

Confined polymerization: ARGET ATRP of MMA in the nanopores of modified SBA-15

Rod-like mesoporous SBA-15 silica particles were surface modified by different silane coupling agents firstly, then polymethyl methacrylate (PMMA) was prepared in the confined nanopores of the SBA-15 via activators regenerated by electron transfer for atom transfer radical polymerization (ARGET ATRP). The PMMA/SBA-15 nanocomposites and PMMAs inside the nanopores were characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), nitrogen adsorption measurements, gel permeation chromatography (GPC), fourier transform infrared spectroscopy (FT-IR), thermogravimetry analysis (TGA), proton magnetic resonance (1H NMR), and differential scanning calorimetry (DSC), respectively. The results demonstrated that the nanopores of SBA-15 could serve as nanoreactors and had great confinement effects on the MMA polymerization. The morphology of PMMAs obtained in the channels was similar to that of intrinsic structure of SBA-15. The thermal stability, molecular weights, isotacticity of PMMAs inside the pores were all increased significantly compared to the conventional PMMA by ARGET ATRP, while broadened the polydispersity index (PDI) values and reduced the syndiotacticity.

Preparation and performance of polyurethane/mesoporous silica composites for coated urea

Polymer/mesoporous silica composites have drawn much attention. In this study SBA-15 mesoporous silicas with three morphologies including fiber, nano-rod and sphere were synthesized and characterized. Polyurethane (PU)/SBA-15 composites were prepared via an in-situ reactive-layer spray technique on urea granules. And the effects of SBA-15 on structure and controlled release performance of coating were elucidated and compared to n-SiO2. The results showed that rod-like SBA-15 with an average particle size of 700nm extremely improved the release properties of PU at the same filler loading, but the other two SBA-15 fillers had no effect on PU instead. SEM images reflected that although SBA-15 particles were all well-dispersed in PU matrix to form a sea-island structure, PU/fiber-like SBA-15 composite coating had some obvious defects. Conversely, n-SiO2 particles of coating gathered and formed large agglomerates without voids. TGA studies suggested that PU/rod-like SBA-15 composite as a coating material had a much higher thermal stability than PU and PU/n-SiO2.

Rapid and Facile Synthesis of Rod-Like Ordered Mesoporous Carbon Material for Dye Adsorption from Aqueous Solution

A rapid and facile synthesis method for rod-like ordered mesoporous carbon material (OMC) was developed, in which the phenolic resin was used as the carbon source and the precursor solution of rod-like SBA-15 was employed as a hard-template. This new method skipped several processes related to the preparation of SBA-15. The as-synthesized OMC featured a rod morphology with rod lengths of 0.7–1 μm, uniformly sized mesopores (5.1 nm), and a high surface area (795 m2 g–1). Furthermore, the as-synthesized OMC showed excellent capacity for dye adsorption from aqueous solution.

Stability, Hydration, and Thermodynamic Properties of RNase A Confined in Surface-Functionalized SBA-15 Mesoporous Molecular Sieves

Mesoporous silicates (MPS) have several advantages for the immobilization of enzymes and large organic molecules. They possess well-defined pores and their surfaces can be functionalized by chemical methods. In this study, the model protein ribonuclease A (RNase A) was encapsulated in unmodified amino- and carboxy-functionalized rodlike SBA-15 with pore widths ranging from 4.0 to 5.8 nm. Differential scanning (DSC) and pressure perturbation (PPC) calorimetric techniques were employed to evaluate the stability, hydration, and volumetric properties of the confined protein. In addition, the influence of the solution pH, the surface functionalization, and cosolvents on the protein immobilization and the thermal stability of the immobilized protein are reported. The extent of stabilization depends strongly on the surface characteristics of the host, such as the charge density, and on geometric parameters, i.e., the pore size and pore volume. The addition of the chaotropic agent urea leads to an increased protein loading. Addition of the kosmotropic agent glycerol has the opposite effect. The stability of the protein RNase A confined in all the mesoporous silicates is drastically enhanced and is of the order of ΔTm ≈ 30 ± 10 °C regarding the increase in temperature stability. The highest immobilization capacity, fastest immobilization rate, and maximum thermal stability was achieved for the surface-functionalized SBA-15-COOH. The increased temperature stability is probably not only due to the entropy-driven excluded volume effect but also due to an increased hydration strength of the protein within the narrow silica pores, similar to the effects compatible osmolytes impose on protein hydration and stability. The absence of an expansivity increase of the confined protein after thermal denaturation indicates that inside the pores complete unfolding of the protein is not feasible anymore.

Comparative Studies on Enzymatic Activity of Porcine Pancreatic Lipase Immobilized onto Functionalized Rod-Like SBA-15 Mesoporous Materials with Aminopropyl and Glutaraldehyde

Rod-like SBA-15 mesoporous materials were synthesized and modified using two-step process through aminopropyl and glutaraldehyde. Aminopropyl was first covalently bonded to silanol groups present on the surface of mesoporous silica. Successively, the reaction of aldehyde with aminopropyl was followed. Immobilizations of Porcine pancreatic lipase (PPL) onto functionalized SBA-15 (NH2-SBA-15-PPL and G-SBA-15-PPL) have been achieved. Relative activities and reusability of NH2-SBA-15-PPL and G-SBA-15-PPL for triacetin hydrolysis have been studied.

Electrospinning of PAN nanofibers incorporating SBA-15-type ordered mesoporous silica particles

The influence of rod-like SBA-15 type ordered mesoporous silica particles, as additives, on the morphology and textural parameters of electrospun polyacrylonitrile (PAN) nanofibers has been studied. PAN charged-webs are prepared by electrospinning of a dispersion of SBA-15 particles in a solution of PAN in DMF. The effect of the applied voltage on the morphology of produced webs has been also investigated. Collected results demonstrate that when electrospinning pristine or charged PAN, the higher the voltage applied, the coarser the fiber is. As a result, sub-micron fibers of PAN charged with SBA-15 particles were obtained. An increase, to some extent, of the specific surface area and pore volume of charged fibers compared to that of pristine electrospun PAN fibers has been also observed. Thermogravimetric analyses reveal that more than 78% of SBA-15 particles are found in the dry fibers. SBA-15 loading rates of 14.3, 15.6 and 27.6wt.% were achieved. Calculations done to estimate the ratio of accessible pore of SBA-15 particles incorporated within the produced fibers show that more than 50% of accessible pores can be obtained. However, there is a saturated capacity of SBA-15 particles distribution on the surface of the nanofibers beyond 15.6wt.% loading of SBA-15.This suggests that the ratio of accessible pores within the charged fibers is also limited.

Effect of template-removing methods and modification to mesoporous blank silica and composited silica

A pluronic template of rod-like mesoporous silica was removed by extraction, calcination, and microwave digestion methods. The results of X-ray diffraction and Fourier Transform Infrared Spectroscopy spectra analyses confirmed that microwave digestion was the most efficient method to remove the template because of its convenience, speed, and effectiveness. The pore surface of rod-like SBA-15 was modified by an organic silane with terminal amino groups. Also Rhodamine 6G dye molecules were grafted onto the mesopore walls of rod-like SBA-15 before and after modification. Blue-shifts in photoluminescence, pore features in N2 adsorption–desorption, transmission electron microscopy results of blank rod-like SBA-15, dye doping rod-like SBA-15 before and after modification confirmed that the mesoporous SBA-15 that had been modified by the organic silane with terminal amino groups was more effective for grafting of Rhodamine 6G molecules because the structures still remained as ordered mesostructures after grafting.

Highly Dispersed Copper Species within SBA-15 Introduced by the Hydrophobic Core of a Surfactant Micelle as a Carrier and Their Enhanced Catalytic Activity for Cyclohexane Oxidation

Highly dispersed copper species were successfully coated onto the inner surface of the rodlike mesoporous SBA-15 silica by a newly developed strategy. The hydrophobic core of the surfactant micelle...