Surfactant Template Research Articles

Advances in Mesoporous Silica Nanoparticles: Synthesis, Characterization, and Biomedical Uses

Mesoporous silica nanoparticles (MSNs) have drawn significant attention due to their exceptional properties and diverse range of applications, particularly in nanomedicine. The distinctive properties of MSNs, such as their high surface area, tunable pore size, and versatile surface chemistry, make them ideal candidates for various biomedical applications. This review aims to present a detailed understanding of MSNs, from synthesis and characterization to their versatile applications in biomedicine, highlighting their significant potential in advancing healthcare technologies. The synthesis methods for MSNs were comprehensively discussed, emphasizing the influence of parameters like solvent, base, alkoxysilane concentrations, and template surfactants on the size and shape of the nanostructures. Different types of MSNs, including MCM-41, SBA-15, KIT-6, and hollow MSNs, are discussed, along with their synthesis protocols and unique characteristics. The review also covers various spectroscopic techniques, such as XRD, XPS, FTIR, NMR, and fluorescence spectroscopy, which are crucial for characterizing MSNs. Furthermore, the biomedical applications of MSNs are highlighted, demonstrating their potential in drug delivery systems, imaging, and diagnostics. The review concludes with a discussion of the future perspectives and challenges in the field, providing insights into potential developments and the prospects for clinical translation.

Green Synthesis of Catalytic 3D Platinum Nanostructures from a Body‐Centered Cubic Pluronic Micellar Array Template

AbstractOrdered and well‐interconnected 3D electrode nanostructures open up exciting perspectives in catalysis, sensing and energy harvesting. Here, highly ordered 3D nano‐sized Pt mesoporous structures based on the I‐Wrapped Package (I‐WP) architecture with 13.5 nm unit cell size, previously unreported for metal nanomaterials, are presented. The samples are synthetized by soft‐template electrodeposition, using the body‐centred cubic (BCC) lyotropic crystalline micellar phase of Pluronic F68 as the template. The specific surface area of the resulting Pt nanoarchitecture is 36 ± 13 m2 g−1. The oxygen reduction reaction kinetic current is 0.98 mA cm−2; the current density normalized by the electrochemical active surface area and the weight of deposited Pt are 0.92 mA cm−2 and 153.53 A g−1, respectively, showing superior properties than conventional Pt nanostructures produced by surfactant templates. These results suggest a nanostructure based on the topology of the I‐WP minimal surface, representing the first case at this length scale from a metallic material, opening up new research directions in fundamental physics based on predicted thermal and phononic properties for this topology. The water‐based template provides a chemical‐free, eco‐friendly route for ordered mesoporous conductive nanomaterials manufacturing, inspiring future trends in the field.

Solid-state surfactant templating for controlled synthesis of amorphous 2D oxide/oxyhydroxide nanosheets

As a member of 2D family, amorphous 2D nanosheets have received increasing attention due to their unique properties that are distinct from crystalline 2D nanosheets. However, compared with the vast library of crystalline 2D nanosheets, amorphous 2D nanosheets are still infancy due to the lack of an efficient synthetic approach. Here, we present a strategy that yields a library of 10 distinct amorphous 2D metal oxides/oxyhydroxides using solid-state surfactant crystals. A key feature of this process is a stepwise reaction using solid surfactant; the solid-state surfactant crystals have metal ions arranged in the interlayer space, and hydrolysis of the metal ions leads to the formation of isolated clusters in the surfactant crystals via limited condensation reactions. Immersing the surfactant crystals in formamide promotes nanosheet formation through the self-assembly of clusters by templating the morphologies of the crystals generated from surfactants crystals. Our approach opens a flatland in amorphous 2D world.

Exploring surface silanols in mesoporous Na-LTA zeolite to enhance its catalytic activity in knoevenagel condensation by grafting amino groups

Mesoporous Na-LTA zeolite was synthesized using the surfactant templating method with the organosilane surfactant [3-(trimethoxysilyl)propyl] octadecyldimethylammonium chloride (TPOAC). The formation of mesopores not only improved the accessibility of the basic catalytic sites but also led to the formation of isolated external silanols. These silanols were used to anchor propylamine groups by reacting with 3-aminopropyltrimethoxysilane (APTMS). The incorporation of propylamine groups in the mesoporous Na-LTA improved its catalytic activity in the Knoevenagel condensation reaction by 40 % due to the presence of extra basic catalytic sites from amino groups. The combination of mesopore generation and functionalization is an efficient strategy for enhancing the performance of Na-LTA zeolite in this reaction.

Highly responsive double-shell ZnO hollow microspheres based gas sensor for acetic acid detection in vinegar

Acetic acid sensing materials for environmental and related food quality control requiring high sensitivity and selectivity, and ppb-level detection limit, remain challenging. Double-shell ZnO hollow microspheres were prepared by a surfactant assisted template method, and the resultant gas sensor showed excellent acetic acid sensing performance. The sensor response reached 116 to 100 ppm acetic acid at 270°C with a short response time of 3.2 s. The relationship between acetic acid concentration and the response was established, and the detection limit reached 100 ppb. DFT theory computational results demonstrated the highest adsorption energy of the ZnO gas sensor to acetic acid among all tested gases, proving its high selectivity to acetic acid. Besides, the unique double-shell hollow structure with abundant oxygen vacancy and large surface area might be the other factors that gave rise to its excellent acetic acid gas sensing performance. Based on the gas sensor, a method for fast quantitative detection of acetic acid content in vinegar was developed. The linear relationship between sensor response and acetic acid gas concentration of vaporized white vinegar was established, and the acetic acid content in the vinegar can be quickly determined. The result proved our acetic acid sensor to be a promising candidate for practical applications.

Systematic study of the implications of calcination and solvent extraction of the surfactant in MCM-41-type mesoporous silica nanoparticles

Mesoporous silica nanoparticles (MSN) have been growing in recent years in a broad range of applications, such as nanomedicine, catalysis, and gas storage. For the preparation of MSN, especially in nanomedicine applications, the extraction of the surfactant template, generally 1-hexadecyltrimethylammonium bromide (CTAB), is required. Several methods to remove the surfactant from MNS have been reported in the literature, such as calcination, solvent extraction, and dialysis. Depending on the method employed, the materials obtained have different properties; however, a systematic study that compares the use of different surfactant extraction methods and their implications in the final characteristics of the MSN has not been reported. Hence, the aim of this work is to study the effect of surfactant removal on MSN by calcination at different temperatures (400 °C, 450 °C, 500 °C and 550 °C) or by extraction with HCl/ethanol or NH4NO3/ethanol. The final materials are fully characterised by different techniques. The study performed shows the removal efficiency when the different methods are used, and their effect on silica condensation degree, mesoporosity, cytotoxicity, and degradation rate. The results allow for obtaining a deeper knowledge of the surfactant removal processes.

Optimisation Studies of Mesoporous Silica Nanoparticle as a Drug Carrier for Gemcitabine: Enhancing Therapeutic Effectiveness in Pancreatic Cancer

Pancreatic cancer, often referred to as “the silent killer”, presents with minimal or no symptoms in its early stages, leading to late detection when surgical resection is no longer the optimal treatment option. Gemcitabine (GEM), one of the leading chemotherapeutic drug for advanced stages of cancer, is a crucial treatment for pancreatic cancer. However, the low 5-year survival rate of pancreatic cancer patients highlight the limited effectiveness of current treatments. In recent years, mesoporous silica nanoparticles (MSNP) have garnered significant attention in both scholarly and pharmaceutical fields due to their unique combination of properties including stable porous structure and high loading capacities. This research aims to investigate the potential of MSNP as a carrier for anticancer drugs, specifically GEM. MSNP was successfully synthesized in the laboratory using sol-gel method with tetraethyl orthosilicate (TEOS) as silica source and cetyltrimethylammonium bromide (CTAB) as surfactant template. Comprehensive morphological and physical characterizations of the MSNP product were performed through transmission electron microscopy (TEM), field emission scanning electron microscopy (FESEM), energy dispersive X-ray (EDX) spectroscopy, element mapping, X-ray diffractometry (XRD), and accelerated surface area porosimetry (ASAP). The results demonstrate that MSNP exhibits desirable properties for drug loading, including a stable mesoporous structure with pore size of ~ 4.94 nm, a high surface area of about 278.32 m²/g, and average particle diameter of approximately 85 nm. The effects of incubation time and initial GEM concentrations were studied to determine the optimal drug loading parameters for the MSNP vehicle. The successful loading of up to 24 µg of GEM in 1 mg of MSNP achieved in an optimized incubation time of 2 hour, validates the tremendous potential of MSNP as a potential anticancer drug carrier in pancreatic cancer treatment. These findings provide a valuable reference for future research and investigations in this promising field.

A Potentially Versatile Enzyme Sensor Platform: Enzyme-Loaded, Tagged, Porous Polymeric Nanocapsules.

Enzymes are essential to life and indispensable in a wide range of industries (food, pharmaceutical, medical, biosensing, etc.); however, a significant shortcoming of these fragile biological catalysts is their poor stability. To address this challenge, a variety of immobilization methods have been described to enhance the enzyme's stability. These immobilization methods generally are specific to an individual enzyme or optimal for a particular application. The aim of this study is to explore the utility of porous, indicator moiety-tagged, polymeric nanocapsules (NCs) for the encapsulation of enzymes and measurement of the enzyme's substrate. As a model enzyme, glucose oxidase (GOx) is used. The GOx enzyme-loaded, fluorophore-tagged NCs were synthesized by using self-assembled surfactant vesicle templates. To show that the biological activity of GOx is preserved during entrapment, the rate of the GOx enzyme catalyzed reaction was measured. To evaluate the protective features of the porous NCs, the encapsulated GOx enzyme activity was followed in the presence of hydrolytic enzymes. During the encapsulation of GOx and the purification of the GOx-loaded NCs, the GOx activity decayed less than 10%, and up to 30% of the encapsulated GOx activity could be retained for 3-5 days in the presence of hydrolytic enzymes. In support of the potentially unique advantages of the enzyme-loaded NCs, as a proof-of-concept example, the fluorophore-tagged, GOx-loaded NCs were used for the determination of glucose in the concentration range between 18 and 162 mg/dL and for imaging the distribution of glucose concentration in imaging experiments.

PEG-PVP-Assisted Hydrothermal Synthesis and Electrochemical Performance of N-Doped MoS2/C Composites as Anode Material for Lithium-Ion Batteries.

Molybdenum disulfide shows promise as an anode material for lithium-ion batteries. However, its commercial potential has been constrained due to the poor conductivity and significant volume expansion during the charge/discharge cycles. To address these issues, in this study, N-doped MoS2/C composites (NMC) were prepared via an enhanced hydrothermal method, using ammonium molybdate and thiourea as molybdenum and sulfur sources, respectively. Polyethylene glycol 400 (PEG400) and polyvinylpyrrolidone (PVP) were added in the hydrothermal procedure as soft template surfactants and nitrogen/carbon sources. The crystal structure, morphology, elemental composition, and surface valence state of the N-doped MoS2/C composites were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), high-resolution transmission electron microscopy (HRTEM), and X-ray photoelectron spectroscopy (XPS), respectively. The results indicate that the NMC prepared by this method are spherical particles with a nanoflower-like structure composed of MoS2 flakes, having an average particle size of about 500 nm. XPS analysis shows the existence of C and N elements in the samples as C-N, C-C, and pyrrolic N. As anodes for LIBs, the NMC without annealing deliver an initial discharge capacity of 548.2 mAh·g-1 at a current density of 500 mA·g-1. However, this capacity decays in the following cycles with a discharge capacity of 66.4 mAh·g-1 and a capacity retention rate of only 12% after 50 cycles. In contrast, the electrochemical properties of the counterparts are enhanced after annealing, which exhibits an initial discharge capacity of 575.9 mAh·g-1 and an ultimate discharge capacity of 669.2 mAh·g-1 after 70 cycles. The capacity retention rate decreases initially but later increases and elevated afterward to reach 116% at the 70th cycle, indicating an improvement in charge-discharge performance. The specimens after annealing have a smaller impedance, which indicates better charge transport and lithium-ion diffusion performance.

Phosphonate functionalized magnetic mesoporous silica for rare earth element recovery from citrate assisted solid waste extracts

The growing high demand of rare earth elements (REEs) has prompted extensive research on REE recovery from waste streams. This study reports the synthesis and evaluation of phosphonate-functionalized magnetic mesoporous silica (MMS-PP) for REE recovery from the acidic extracts of solid wastes. MMS-PP was synthesized using surfactant template and post-synthesis methods, and tested using simulated and real extraction solutions from citrate-assisted REE extracts from municipal solid waste incineration (MSWI) ash. The organic-inorganic hybrid MMS-PP was evaluated for La recovery from 50 mM simulated citrate extract, with the adsorption capacity of 13.5 mg/g compared to ∼2.5 mg/g for non-functionalized MMS. The MMS-PP material exhibited fast adsorption within 10 min, good La selectivity against competing Na+ and Ca2+, moderate selectivity against Al3+ and Fe3+, high recyclability over multiple adsorption-desorption cycles, and equivalent efficiency for La, Ce, Nd, and Y recovery. The MMS-PP material also demonstrated 70–95% REE recovery from real citrate extracts of MSWI ash, and the spent MMS-PP material can be regenerated and reused for multiple cycles. Functionalized mesoporous materials in combination with organic-ligand assisted extraction can potentially provide a green, effective, and tunable solid-liquid separation platform for REE recovery from complex solid waste streams.

Sustainable synthesis of titanium based photocatalysts via surfactant templating: from kerosene to sunflower oil

Sunflower oil was used as a templating agent for the development of sustainable, novel porous, titanosilicate microspheres. They are highly effective in removal of organic pollutants from water via adsorption and photocatalysis, and have potential applications in advanced tertiary water-treatment.

"Synthesis and characterization of mesoporous V–Mo-MCM-41 nanocatalysts: Enhancing efficiency in oxalic acid synthesis"

Mesoporous V–Mo-MCM-41 nano molecular sieves were synthesized via the direct hydrothermal method, employing tetraethyl orthosilicate (TEOS) as a silica source and cetyltrimethylammonium bromide (CTAB) as a surfactant template. Comprehensive characterization through N2-adsorption (BET), Fourier-transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), and scanning electron microscopy-energy-dispersive X-ray spectroscopy (SEM-EDX) confirmed the mesoporous nature of the catalysts, revealing variations in specific surface area and a significant pore diameter of 6.3 nm, enhancing their versatility for various chemical transformations. The nanoscale structure was further validated through XRD analysis and SEM images. The catalytic efficiency of V–Mo-MCM-41 was demonstrated by synthesizing oxalic acid from molasses, and a response surface methodology (RSM) study on four key variables revealed a maximum yield of 83 % within 1 h using minimal sulfuric acid, showcasing the effectiveness of the prepared catalysts.

Supercapacitance Performance of Mesoporous Mono- and Bi-Metallic Cobalt and Nickel Hydroxides Nanoflakes Chemically Deposited from Foam-Surfactant Liquid Crystal Dual Templates

Mesoporous 2D nanoflakes architectures of mono- and bi-metallic cobalt and nickel hydroxide (meso-Co-Ni(OH)2) hybrids were synthesized using novel chemical precipitation of foam-surfactant liquid crystal dual template (FSDT). The dissolved cobalt and nickel ions within the aqueous region of the Brij®78 surfactant template was reduced by the excess of sodium borohydride reducing agent that simultaneously generates excessive hydrogen foam as a double template. The physicochemical characterizations of the mono- and bi-metallic nanostructured Co-Ni(OH)2 hybrids performed using X-ray diffraction, surface area analyzer, scanning and transmission electrons microscopic techniques showed the formation of highly mesoporous hydroxides 2D nanoflakes architectures having an amorphous structure and surface area up to 253.50 m2/g. The electrochemical and supercapacitance evaluation of the mono-, and bi-metallic mesoporous hydroxides showed excellent Faradaic supercapacitance performance within a wider potential window and a higher charge and discharge rate. In particular the mesoporous monometallic of Co(OH)2, Ni(OH)2, bimetallic Co-Ni(OH)2 with Co/Ni ratios of (1:1), and (1:3), hydroxides showed total capacitances of 204, 869, 943, and 1384, F/g at charging current density of 5.0 A g−1 respectively and capacity retention rate of approximately 99.4% after 300 cycles. This suggests that these materials hold promise as electrode materials for energy storage applications.

Cationic micelles in deep eutectic solvents: effects of solvent composition.

Deep eutectic solvents (DES) are mixtures of hydrogen bond donors and acceptors that form strongly hydrogen-bonded room temperature liquids. Changing the H-bonding components and their ratios can alter the physicochemical properties of deep eutectic solvents. Recent studies have shown p-toluenesulfonic acid (pTSA) forms room temperature liquids with choline chloride (ChCl) at different molar ratios: 1 : 1, 1 : 2 and 2 : 1 [Rodriguez Rodriguez et al., ACS Sustain. Chem. Eng., 2019, 7(4), 3940]. They also showed that the composition affects the physical properties of these liquids and their ability to dissolve metal oxides. In this work we evaluate the solubility and self-assembly of cationic surfactants alkyltrimethyl ammonium bromides (CnTAB) in these pTSA/ChCl based liquids. CnTABs are insoluble in 1pTSA : 2ChCl, whereas in 1pTSA : 1ChCl and 2pTSA : 1ChCl they form micelles. We characterise CnTAB (n = 12, 14, 16) micelles using small angle neutron scattering and also look at interaction of water with the micelles. These studies help determine the interaction of DES components with the surfactant and the influence of varying pTSA and water ratios on these interactions. This provides potential for controlled surfactant templating and for tuning rheology modification in such systems.

Synthesis and Characterization of Core-Shell Mesoporous Iron oxide Magnetic Nanoparticles using Modified Co-Precipitation Method

In recent era, development of nanotechnology is an art of delivery of drug by improving its compatibility, effectiveness and efficacy. Among all nanoparticles, magnetic nanoparticles play a predominant role to shows their targeted drug delivery using a magnetic field, also helps to diagnose the diseases like cancer. The present study included preparation of four different mesoporous nanoparticles using the Pluronic block copolymer P123 as a surfactant template, then insert iron oxides using co-precipitation method. The resulted formed mesoporous magnetic nanoparticles are examined for structural characters by using FTIR, XRD, HRSEM and Elemental Mapping techniques. The results of X-ray diffraction (XRD) showed that the formed composites conserved ordered mesoporous structure after the formation of iron oxide nanoparticles in the pores. FTIR results indicated that the surface contains silanol group and Fe–O on the surface of the materials at 1060 cm-1 and 1020 cm-1 peaks respectively. Scanning electron microscopy (SEM) results showed that all mesoporous magnetic nanoparticles within the range of size from 50 to 100nm also possessed a regular spherical shape. These particles possessed high surface area, high pore volume and showed magnetic response sufficient for drug targeting in the presence of an external magnetic field. Elemental mapping data indicated about the percentage of all elements present in the mesoporous materials. We concluded that all four types of magnetic nanoparticles are structurally arranged in their structure with sufficient percentage of elements on their particle surface along with good size range. Further loading of drug into all types of magnetic nanoparticles decides the loading efficiency, stability and drug release nature.

Soft-templated mesostructured TiO2 - SiO2 composites with high thermal stability

To overcome the drawbacks of pure mesostructured titania and in particular the low thermal stability, in this study we have investigated in detail the effect of Si4+ addition on the properties of mesostructured TiO2 prepared by combining the sol-gel process and the surfactant templating mechanism. Obtained materials have also been tested for the photodegradation of methyl orange, used as a model dye.From the SAXS and the manometry nitrogen adsorption-desorption analyses, it can be concluded that the presence of Si4+ delays the collapse of the mesopores network. Compared to the bare mesostructured TiO2, the XRD and Raman results show that the anatase and the rutile phases appear at higher temperature. The higher the Si4+ content, the higher the amorphous-anatase and rutile anatase-phase transition temperatures. The delay in the crystallization also allows the detection of the TiO2-β phase, which is an anatase phase with oxygen vacancies. These phenomena have been attributed to the « glass effect ». In that case, amorphous SiO2, which is formed during the synthesis, surrounds the titania particles and inhibits their growth, when the heating temperature is increased. By this way, the thermal stability of the mesostructured titania containing Si4+ is enhanced.Photocatalytic experiments highlight the importance of the presence of the anatase phase for the discoloration efficiency of the dye solution. Indeed, the increase of Si4+ leads to a clear decrease of the photodegradation efficiency.

A hierarchical spatial assembly approach of silica-polymer composites leads to versatile silica/carbon nanoparticles.

Assembly of silica and polymer in the absence of surfactant templates is an emerging strategy to construct intricate nanostructures, whereas the underlying mechanism and structural versatility remain largely unexplored. We report a hierarchical spatial assembly strategy of silica-polymer composites to produce silica and carbon nanoparticles with unprecedented structures. The assembly hierarchy involves a higher length scale asymmetric A-B-A core-shell-type spatial assembly in a composite sphere, and a nanoscale assembly in the middle layer B in which the silica/polymer ratio governs the assembled structures of silica nanodomains. Through an in-depth understanding of the hierarchical spatial assembly mechanism, a series of silica and carbon nanoparticles with intriguing and controllable architectures are obtained that cannot be easily achieved via conventional surfactant-templating approaches. This work opens an avenue toward the designed synthesis of nanoparticles with precisely regulated structures.

Chemical deposition from a liquid crystal template: A highly active mesoporous nickel phosphate electrocatalyst for hydrogen green production via urea electro-oxidation in an alkaline solution

Recently the urea and urinated wastewater electrolysis process has shown promising technology for hydrogen fuel green production in addition to denitrification of wastewater. However, to make the process economically valuable, the electrocatalysts nanoarchitecture, nanometer size, shape, facets, and composition need to be engineered to boost the urea oxidation reaction (UOR). This work demonstrates a simple and novel approach to the synthesis of mesoporous nickel phosphate nanoparticles (meso-NiPO) via chemical deposition from a surfactant liquid crystal template. Typically, the nickel ions dissolved in the aqueous domain of the hexagonal liquid crystalline phase of the Brij®78 template were chemically reacted with the sodium phosphate solution to precipitate the mesoporous nickel phosphate nanoarchitecture after washing up the surfactant. The physicochemical characterizations show the meso-NiPO exhibits an amorphous highly mesoporous structure with a higher specific surface area (43.50 m2/g) compared to the bare nickel phosphate (bare-NiPO, 4.26 m2/g) prepared in the absence of surfactant. The electrochemical performance of meso-NiPO electrocatalyst for the urea oxidation reaction in alkaline solution exhibits superior activity including a lower oxidation onset potential (0.30 V vs. Ag/AgCl), charge transfer resistance (3.35 O) and mass activity of 700.7 mA/cm2 mg at the oxidation potential of 0.6 V vs. Ag/AgCl. Moreover, the meso-NiPO reveals long-term stability, and 97.5% of the steady-state oxidation current was maintained after the 3-hour urea electrolysis test. Using an H-shape urea electrolyzer, the corresponding cathodic hydrogen production rate reached 415 µmol/h and a Faradic efficiency of 96.8 % at an applied bias of 2.0 V. The electroactivity high performance of the mesoporous nickel phosphate is ascribed to the high specific surface area and mesoporous architecture that provide efficient charge transfer, as well as mass transport of the electroactive species. The chemical deposition from a surfactant liquid crystal template has the advantages of a one-pot template, applicable to the synthesis of a wide range of nanomaterials with various compositions and nanoarchitectures at room temperature for application in electrochemical energy production and storage systems.

Newly design and synthesis of Ni–Ir–Ru-doped mesoporous silica open-frameworks for admirable electrochemical water-oxidation application

As traditional non-renewable energy sources become scarcer, researchers are exploring effective strategies for producing sustainable and renewable energy. Oxygen evolution reaction through electrocatalytic water splitting (EC-OER) on the surface of a semiconductor has drawn much more attention in the worldwide as it has the principal role towards the several kind of energy applications viz. fuel cell, metal-ion rechargeable batteries and water oxidation. It is extremely difficult to develop eco-friendly, plentiful, and cost-effective nanomaterials as catalysts in order to achieve high efficiency of hydrogen production through water splitting. Furthermore, hierarchical nanostructures will become more valuable in future energy conversion applications due to their excellent physicochemical properties. Herein, we have synthesized total six different kinds of multi-metal-doped porous silica nanomaterials by utilizing the combination of nickel, iridium, and ruthenium metal slats in order to explore them as potential catalysts for electrochemical water oxidation process. We present a simple strategy to synthesize multi-metal-doped silica materials with spherical morphology, deploying a cation surfactant template (CTAB) as a structure directing agent in water-ethanol solvent mixtures. These materials are thoroughly characterized with the help of powder X-ray diffraction (PXRD), UV–Vis, FT-IR, X-ray photoelectron spectroscopy (XPS), high resolution transmission electron microscopy (HR-TEM), field emission scanning electron microscopy (FE-SEM), nitrogen-sorption isotherm, thermogravimetric (TGA) analysis. The particles are 550–600 nm in size with a fine-looking spherical morphology and surface area in the range of 111–419 m2/g. Among all of these metal-silica, Ni–Ir–Ru-doped mesoporous silica particles (NIRS) exhibit excellent electrocatalytic activity towards oxygen evolution reaction (100 mA/cm2 current density@0.5V) with long-term durability up to 10 h, and the Tafel slope is also very low (∼68 mV/dec) in 1 M KOH medium. The excellent electrical conductivity of Ni–Ir–Ru-doped silica makes it a superior electrocatalyst due to its spherical morphology, synergistic effects of the multi metallic components, and its hierarchical nanoporous structure.

The effect of the number of hydrophobic tails of cationic ammonium surfactants on mesoporous TiO2 synthesized

Mesoporous titanium dioxide (TiO2) is one of the most studied mesoporous materials considering its special character and various applications. In the present work, mesoporous TiO2 was synthesized by a sol–gel method employing different hydrophobic tails of ammonium cationic surfactants templates. The prepared samples were characterized by various techniques. The XRD profiles confirmed that all samples crystallized into the TiO2 anatase phase. The crystallite size of all samples was found to vary in the range of 8.60 nm to 13.61 nm. The transition temperature of the anatase phase was increased to several Celsius degrees since TiO2 was fabricated with a template assistant. The surface area of the mesoporous TiO2 was increased in the range of 93 m2.g−1 (CTAB) − 116.8 m2.g−1 (MTAB). These values were larger than the TiO2 synthesized without a template (72 m2.g−1). The total pore volume was also increased between 0.1704 cm3.g−1 (CTAB) and 0.300 cm3.g−1 (MTAB), while the TiO2 synthesized without a template was only 0.161 cm3.g−1. Using CTAB and DDAB yield a uniform mesopore size distribution. MTAB tends to produce non-uniform pore of the mesoporous system. The soft-templating method opens up new possibilities for synthesizing mesoporous metal oxides.