•Green synthesis of iron oxide nanoparticles using Punica granatum peel extract•The synthesis of nanoparticles was controlled by using various plant peel extract concentrations.•The prepared nanoparticles were screened for their antibacterial activity.A green approach to fabricate nanoparticles has been evolved as a revolutionary discipline. Eco-compatible reaction set ups, use of non-toxic materials and production of highly active biological and photocatalytic products are few benefits of this greener approach. Here, we introduce a green method to synthesize Fe oxide NPs using Punica granatum peel extract. The formation of Fe oxide NPs was optimized using different concentrations of peel extract (20 mL, 40 mL and 60 mL) to achieve small size and better morphology. The results indicate that the FeNPs, obtained using 40 mL concentration of peel extract possess the smallest size. The morphology, size and crystallinity of NPs was confirmed by implementing various techniques i.e. UV–Vis spectroscopy, X-ray diffraction, Scanning Electron Microscopy and Electron Diffraction Spectroscopy. The bio-chemicals responsible for reduction and stabilization of FeNPs were confirmed by FT-IR analysis. The biogenic FeNPs were tested for their size dependent antibacterial activity. The biogenic FeNPs prepared in 40 mL extract concentrations exhibited strongest antibacterial activity against Pseudomonas aeruginosa i.e. 22 (± 0.5) mm than FeNPs with 20 mL and 60 mL extract concentrations i.e. 18 (± 0.4) mm and 14 (± 0.3) mm respectively. The optimized FeNPs with 40 mL peel extract are not only highly active for ROS generation but also show no hemolytic activity. Thus, FeNPs synthesized using the greener approach are found to have high antibacterial activity along with biocompatibility. This high antibacterial activity can be referred to small size and large surface area.Download high-res image (97KB)Download full-size image

•Preparation of PtNPs by green method•Taraxacum laevigatum plant extract was used as a reducing source.•Antibacterial activity of PtNPs against P. aeruginosa and B. subtilisThe increase in the severe infectious diseases and resistance of the majority of the bacterial pathogens to the available drug is a serious problem now a day. In order to overcome this problem it is necessary to develop new therapeutic agents which are non-toxic and more effective to inhibit these microbial pathogens. For this purpose the plant extract of highly active medicinal plant, Taraxacum laevigatum was used for the synthesis of platinum nanoparticles (PtNPs) to enhance its bio-activities. The surface plasmon resonance peak appeared at 283 nm clearly represent the formation of PtNPs. The results illustrate that the bio-synthesized PtNPs were uniformly dispersed, small sized (2–7 nm) and spherical in shape. The green synthesized PtNPs were characterized by UV–vis spectroscopy, XRD, TEM, SEM, EDX, DLS and FTIR. These nanoparticles were tested against gram positive bacteria (Bacillus subtilis) and gram negative bacteria (Pseudomonas aeruginosa). The bio-synthesized PtNPs were examined to be more effective against both of the bacteria. The results showed, that the zone of inhibition of PtNPs against P. aeruginosa was 15 (± 0.5) mm and B. subtilis was 18 (± 0.8) mm. The most significant outcome of this examination is that PtNPs exhibited strong antibacterial activity against P. aeruginosa and B. subtilis which have strong defensive system against several antibiotics.Graphically representation of the formation of PtNPs from plant extract and Pt ions and their characterization and antibacterial activity.

A novel highly dispersed bifunctional catalyst Pt@Fe-MCM-41 was prepared successfully by an in situ synthesis combined with selective reduction. The catalyst contained highly dispersed metal active components and acid carriers with a regular structure. The results showed that the uniformly sized platinum nanoparticles were highly dispersed and fixed in the inner surface of MCM-41 and the iron atoms were tetrahedrally coordinated and highly dispersed in the silica framework. The samples showed an excellent catalytic activity and selectivity for hydrocracking of residual oil, which proved that there existed an obvious promotion effect between the highly dispersed platinum active sites and the Fe-MCM-41 carrier.

•Preparation of Au/TiO2 by green deposition method.•Ranunculus muricatus plant extract was used as a reducing source.•Photo inhibition activity of Au/TiO2 against S. aureus.The gold decorated titanium dioxide (Au/TiO2) nanocomposite was synthesized by a novel and ecofriendly green deposition method using phytochemicals from the aqueous extract of Ranunculus muricatus. The prepared nanomaterials were characterized by XRD, HRTEM, SEM and FT-IR techniques. The resulted nanomaterials were tested for photo inhibition of S. aureus and E. coli. The light irradiated Au/TiO2 exhibited significant photo inhibition efficiency against S. aureus 22(±0.6 mm) and E. coli 16(±0.4 mm) than in dark. The promising photocatalytic activity of the nanocomposite may be attributed to the highly decorated AuNPs over the surface of TiO2.

•Preparation of Ag/TiO2 by a novel green method•Cestrum nocturnum leaf extract was used as a reducing source•Photo inhibition activity of TiO2 and Ag/TiO2 against two bacteria•MIC, durability and effect of irradiation time was also analyzed•Photo degradation of methylene blue by Ag/TiO2 and TiO2Water purification is one of the worldwide problem and most of the conventional methods are associated with a number of drawbacks. Therefore it is the need of the day to develop new methods and materials to overcome the problem of water purification. In this research work we present a simple and green approach to synthesize silver decorated titanium dioxide (Ag/TiO2) nanocomposite with an efficient photo catalytic activities. Phytochemicals of the Cestrum nocturnum leaf extract were used to synthesize silver nanoparticles (AgNPs), Titanium dioxide (TiO2) and Ag/TiO2 nanocomposite. To confirm the formation, crystal structure, particle size and shape of green synthesized nanoparticles and nanocomposite, they were characterized by UV–visible spectroscopy (UV–vis), X-ray diffraction spectroscopy (XRD), high resolution transmission electron microscopy (HRTEM), Scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FT-IR). The AgNPs, TiO2 and Ag/TiO2 were evaluated for photo degradation of methylene blue (MB) and photo inhibition of Bacteria. The bio-synthesized Ag/TiO2 nanocomposite was observed to have strong catalytic activities for photo reduction of MB and photo inactivation of bacteria as compared to bare AgNPs and TiO2. In the presence of Ag/TiO2, 90% of MB was degraded only in 40 min of irradiation. Alternatively the bare AgNPs and TiO2 degraded less than 30% and 80% respectively of MB even in more than 100 min of irradiation. Similarly the Ag/TiO2 has very strong photo inhibition efficiency towards Escherichia coli and Pseudomonas aeruginosa. The zone of inhibition of irradiated Ag/TiO2 nanocomposites against E. coli and P. aeruginosa was 19 mm and 17 mm respectively which was two times higher than in dark. These promising photocatalytic activities of nanocomposite may be due to the highly decorated AgNPs over the surface of TiO2.

•Green synthesis of PdNPs is using Sapium sebiferum leaf extract.•The synthesized PdNPs were well dispersed, small size and spherical in shape.•Investigation of temperature, extract concentration on the size and shape of PdNPs•The PdNPs were screened for inactivation of bacteria.•The PdNPs were also evaluated for photo degradation of methylene blue.There is a growing need to introduce eco-friendly and sustainable procedures for the synthesis of metal nanoparticles that include a mild reaction conditions, simple reaction setup, use of nontoxic medium such as water and plant extract, cost effectiveness as well as greater efficiency for biomedical and catalytic applications. For this purpose, small and highly dispersed palladium nanoparticles (PdNPs) were prepared by eco-friendly and cost effective green method using water soluble leaf extract of Sapium sebiferum as a reducing and capping agent. The formation of PdNPs was optimized at various temperatures i.e. (30 °C, 60 °C and 90 °C) and different leaves extract (5 mL and 10 mL) in order to control their size and shape. The results indicated that PdNPs synthesized at 10 mL leaf extract concentration and 60 °C temperature have small sized (5 nm) and spherical shape. The nanoparticles formation, their dispersion, size and shape were confirmed by various characterization techniques i.e. UV–Vis spectroscopy, Fourier-transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM), thermo gravimetric analysis (TGA) and Dynamic light scattering technique (DLS) analysis. The biologically synthesized PdNPs were tested for size dependent photo degradation of methylene blue and inactivation of bacteria. The PdNPs synthesized at optimized condition (10 mL extract concentration and 60 °C) have strong photo catalytic activity and reduced 90% methylene blue in 70 min. The optimized PdNPs also showed strong bacterial inhibition against Staphylococcus aureus 29(± 0.8 mm), Bacillus subtilis 19(± 0.6 mm) and pseudomonas aeruginosa 11(± 0.6 mm). The results of this examination demonstrate effective applications of extremely active PdNPs.Green synthesis of palladium nanoparticles and their catalytic and biological applications.

•Green synthesis of Au nanoparticles using Salvadora persica stem extract.•The synthesized Au nanoparticles were well dispersed, small size (10–30 nm) and spherical in shape.•Effect of stem extracts concentration on the size, shape and dispersion of Au nanoparticles.•The Au nanoparticles were screened for chemocatalytic reduction of 4-nitrophenol to 4-aminophenol.•Effect of different amounts of AuNPs, and particle size, shape and dispersion on the chemocatalytic activity.A novel and eco-friendly green procedure was developed for the synthesis of Au nanoparticles using stem extract of Salvadora persica. This plant stem extract provides a favorable environment for the formation of small size and well dispersed Au nanoparticles within 15–30 nm diameter. The Au nanoparticles were characterized by UV–vis spectroscopy, XRD, HRTEM, SEM, EDX and FT-IR. The particle size and morphology of Au nanoparticles were also investigated at different stem extract concentrations. The results showed that lesser the concentration of stem extract, spherical and small will be the size of Au nanoparticles. The present research indicated that the green synthesized Au nanoparticles can be used as an effective catalyst for the chemocatalytic reduction of 4-NP to 4-AP. Various factors i.e. catalyst amounts and particle size and shape that affect the chemocatalytic reduction of 4-NP to 4-AP were also studied. The results showed that Au nanoparticles synthesized at 15 vol.% extract's concentration have strong chemocatalytic activity and reduced 4-NP only within 3 min. It may be due to the single spherical shape and small size of Au nanoparticles.

A series of highly dispersed nickel nanoparticles supported by silica pillared clay (SPC) have been synthesized with a facile process. The synthesized samples were characterized by XRD, HRTEM, SEM, IPC-ES, FTIR, N2 adsorption–desorption isotherm and XPS techniques. The results suggest that the materials possess highly ordered mesoporous structure and the highly dispersed nickel nanoparticles with a uniform size of about 4.7 nm are in an ordered configuration in the silica pillared clay's pores. Moreover, the nickel catalysts exhibit high catalytic performance for the hydrodechlorination of chlorobenzene, about 97.8% at 6 wt% Ni-content, and better reusability.

An MFI zeolite nanosheet-pillared montmorillonite clay (MPC) composite material has been synthesized under hydrothermal conditions by a recrystallization method. The hierarchical porous material possesses uniform micropores in the crystalline zeolite pillars and uniform mesopores between the zeolite pillars in the clay interlayer galleries. The MPC material exhibited higher activity and better selectivity in hydrocracking of residual oil than either MFI or the montmorillonite clay pillared with silica (SPC) or the mixture of both.

A series of bimetallic mesostructured V–Ti–MCM-41 molecular sieves with high surface area and narrow pore-size distribution were obtained by a hydrothermal crystallization method. The obtained products were characterized by a series of techniques including X-ray fluorescence, X-ray diffraction, high-resolution transmission electron microscopy, N2 adsorption–desorption, Fourier-transform infrared spectroscopy, X-ray photoelectron spectroscopy and diffuse reflectance ultraviolet-visible spectroscopy. Characterization results showed that the V–Ti–MCM-41 samples remain in a relatively ordered hexagonal structure. V and Ti atoms were incorporated into the silicon framework. The highest phenol selectivity of 94.7% and benzene conversion of 22.3% are obtained over the 3V–5Ti–MCM-41 sample using H2O2 as an oxidant. In addition, the catalytic performance did not decrease after being recycled four times.

•Ni-MCM-41 with high nickel content was synthesized via a facile method.•The nickel atoms were mainly in the framework with tetrahedral coordination.•The samples exhibited excellent catalytic performance for hydrocracking.The well-ordered Ni-MCM-41 with high nickel content was synthesized by a direct hydrothermal method using cetyltrimethylammonia bromide as the structure-directing agent in an ammonia aqueous solution. The resulting samples were characterized by X-ray diffraction, X-ray fluorescence spectroscopy, high-resolution transmission electron microscopy, nitrogen adsorption–desorption isotherms, H2 temperature-programmed reduction analyses, Fourier-transform infrared spectroscopy, ammonia temperature programmed desorption, and X-ray photoelectron spectroscopy. The results indicated that the material maintained ordered physical mesostructure of MCM-41 with high nickel content, and the nickel atoms were mainly in the framework with tetrahedral coordination. The materials possessed high specific surface area (800–580 m2 g−1), large total pore volume (1.05–1.22 cm3 g−1) and pore diameter (2.77–3.16 nm). The material exhibited excellent catalytic performance for the hydrocracking of coker wax oil, which was improved with the increasing of Ni content in the framework of the molecular sieves.Ni-MCM-41 with high nickel content in the framework with highly ordered two-dimensional hexagonal mesostructure was prepared.

•Bio-syntheses of gold nanoparticles using Nerium oleander leaf extract.•Gold nanoparticles was found to be Spherical and well dispersed with small size of 10 nm.•The biogenic gold nanoparticles have excellent antioxidant activity.In the present work we describe the reduction of gold ions into gold nanoparticles using Nerium oleander leaf extract in the one step green synthetic method. The formation of gold nanoparticles was confirmed by UV–vis spectroscopic analysis. The gold nanoparticles were characterized by HRTEM, SEM and were found to be small size (2–10 nm), almost spherical in shape and highly dispersed without any aggregation. The XRD confirmed crystal structure of gold nanoparticles. EDX detector was used to determine the elemental composition of material. The types of organic compounds present in the plant leaves were detected by FT-IR spectral analysis. The gold nanoparticles synthesized by this method were pure and showed good antioxidant activity. The results showed that the N. oleander leaf extract is very active for reduction of gold nanoparticles.

•Green synthesis of AgNPs using Cirsium arvense plant extract.•The AgNPs were well dispersed, spherical shape and small sized (< 15 nm).•We determined the effect of extract concentration and pH on the formation of AgNPs.•The AgNPs were screened for photo inactivation of E. coli.•Effect of irradiation time, size and shape of AgNPs on the inhibition of E. coli.The silver nanoparticles (AgNPs) were green synthesized using Cirsium arvense plant extract as a reducing and stabilizing agent, with superior photo inactivation activity against Escherichia coli (E. coli). The synthesized AgNPs had crystalline structure and were characterized by UV–vis spectroscopy, XRD, HRTEM, SEM, EDX and FT-IR. The formation of nanoparticles was observed at different pH and different plant extract concentrations and it was found that at higher pH (pH > 6) and at lower concentration (10 mL), the reducing and stabilizing efficiency of plant extract was increased. The synthesized AgNPs had small size (< 15 nm) and spherical shape. The AgNPs were evaluated for antibacterial activity against E. coli. Before transferring it to antibacterial activity, it was placed under visible light for 120 min. The same experiment was performed in dark as a control medium. The photo irradiated AgNPs were observed to be more effective against E. coli. The results showed, that the diameter of zone of inhibition of visible light irradiated AgNPs against E. coli was 23 (± 0.5) mm and in dark was 11 (± 0.4) mm.

A novel liquid template corrosion (LTC) method has been developed for the synthesis of layered silica materials with a variety of morphologies, including hollow nanospheres, trilobite-like nanoparticles, spherical particles and a film resembling the van Gogh painting ‘Starry Night’. Lamellar micelles and microemulsion droplets are first formed in an oil–water (O/W) mixture of ethyl acetate (EA), cetyltrimethylammonium bromide (CTAB) and water. After adding aqueous ammonia the EA becomes hydrolyzed, which results in corrosion of microemulsion droplets. These droplets subsequently act as templates for the synthesis of silica formed by hydrolysis of tetraethyl orthosilicate. The morphological evolution of silica can be tuned by varying the concentration of aqueous ammonia which controls the degree of corrosion of the microemulsion droplet templates. A possible mechanism is proposed to explain why the LTC approach affords layered silica nanostructured materials with various morphologies and nanolayer thickness (2.6–4.5 nm), rather than the usual ordered mesostructures formed in the absence of EA. Our method provides a simple way to fabricate a variety of building blocks for assembling nanomaterials with novel structures and functionality, which are not available using conventional template methods.

Magnetic Fe3O4@hierarchical hollow silica spheres (Fe3O4@HHSS) with high specific surface area (SBET) were successfully synthesized by the microemulsification method. The microstructure and properties of Fe3O4@HHSS were studied by SEM, HRTEM, XRD, BET, and VSM techniques. The inner wall of Fe3O4@HHSS is composed of small hollow nanospheres and Fe3O4 nanoparticles, and the small hollow nanospheres and Fe3O4 nanoparticles are covered with an external silica wall. As a magnetic material, the Fe3O4@HHSS showed good magnetic response and could be easily recovered by an external magnet. The Fe3O4@HHSS exhibited an excellent ability to adsorb methylene blue (MB) from aqueous solutions with maximum MB adsorption capacity of 71.45 mg/g. The adsorption process was chemisorption in nature, while the adsorption isotherm data were well fitted to the Langmuir model and the kinetic data were well fitted to the pseudo-second-order kinetic model. Furthermore, the dye saturated Fe3O4@HHSS could be regenerated by using acidic ethanol solution, and the Fe3O4@HHSS showed excellent reusability.

Highlights•Ni nanoparticles highly dispersed in MCM-41 with an ordered distribution.•Ni/MCM-41 composite catalysts prepared by crystal lattice locating method.•The materials possess highly ordered hexagonal mesostructure.•The highly dispersed nickel nanoparticles with a uniform size smaller than 20 nm.•The materials exhibit excellent catalytic performance in reaction of HDC of CB.Ni/MCM-41 materials in which highly dispersed nickel nanoparticles with an ordered distribution were successfully prepared by crystal lattice locating method. The synthesized samples were characterized by XRF, XRD, XPS, HRTEM, and N2 adsorption–desorption isotherm techniques. The results suggest that the materials possess highly ordered hexagonal mesostructure of MCM-41 and the highly dispersed nickel nanoparticles with a uniform size smaller than 20 nm are in an ordered configuration in MCM-41 matrix. The materials with high specific surface area, large pore volume, and big pore diameter exhibit an excellent catalytic performance in hydrodechlorination of chlorobenzene.Graphical abstractThe Ni/MCM-41 materials in which highly dispersed nickel nanoparticles in ordered distribution was successfully prepared by using crystal lattice locating method.

•Lacunary polyoxometalate encapsulated into the molecular sieves HMS.•Lacunary polyoxometalate are dispersed uniformly in the samples.•Samples possess an ordered structure with ribbing to cobweb shape cavity framework.•The samples show excellent catalytic performance for esterification.The lacunary polyoxometalate (LPOM) encapsulated into the hexagonal mesoporous silica matrix materials were successfully prepared via a directly synthesis method by adjusting pH of the preparation system from 2.0 to 6.0. The materials were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, N2 adsorption–desorption measurements, scanning electron microscopy, X-ray fluorescence analysis, and high-resolution transmission electron microscopy. The results show that the samples possess an ordered pore structure with which changed from uniform ribbing-type to cobweb shape cavity along with the LPOM content increasing from 0% to 30%. The materials possess a high specific surface area of 878–626 m2 g−1 and a mesopore diameter of about 3.8 nm. They also show an excellent catalytic performance and a good reusability for the esterification of n-butanol with acetic acid.Lacunary polyoxometalate was encapsulated into the molecular sieves HMS to prepare hybrid catalysts which possess an ordered structure with a ribbing-type to a cobweb shape cavity framework and exhibit an excellent catalytic performance in esterification.

•Ag–AgBr was encapsulated in novel mesoporous hierarchical hollow silica sphere.•The Ag–AgBr@HHSS can be synthesized by a one-pot method.•The Ag–AgBr@HHSS has hierarchical mesoporous hollow structure.•The Ag–AgBr@HHSS shows enhanced photocatalytic activity under visible light.A novel visible light response Ag–AgBr@HHSS photocatalyst (Ag–AgBr encapsulated in hierarchical hollow silica spheres) was synthesized by a facile one-pot method using CTAB as template. The as-synthesized photocatalyst was characterized by techniques of XRD, SEM, EDS, TEM, N2 adsorption–desorption analysis and UV–Vis diffuse reflectance spectra. Structural characterization indicated that the as-synthesized Ag–AgBr@HHSS photocatalyst possessed a small-hollow-sphere@big-hollow-sphere structure with a diameter of 90–150 nm and a high specific surface area of 540 m2/g. The Ag–AgBr nanoparticles with average crystallite size of 7.5 nm were encapsulated dispersedly in the HHSS matrix. The photocatalytic activity of the photocatalyst was investigated by the degradation of methyl orange under visible light irradiation. Due to its smaller Ag–AgBr particle size and special hollow structure, the Ag–AgBr@HHSS showed higher photocatalytic activity than Ag–AgBr/MCM-41. The Ag–AgBr@HHSS exhibited good reusability and maintained more than 93% of the initial photocatalytic activity even after 5 runs of recycling.Graphical abstractA novel visible light response Ag–AgBr@HHSS photocatalyst (Ag–AgBr encapsulated in hierarchical hollow silica spheres) was successfully synthesized for the first time. The Ag–AgBr nanoparticles were dispersed well in hierarchical hollow silica sphere matrix. Compared with Ag–AgBr/MCM-41, the Ag–AgBr@HHSS showed enhanced photocatalytic activity during the photocatalytic degradation of MO.

•The foamed titania–silica composite was synthesized by one-pot method.•The composite possesses foamed structures with cavities and mesoporous shells.•The composite showed enhanced photocatalytic activity.A novel foamed titania–silica composite (FTSC) with hierarchical porous structures was prepared by a one-pot microemulsion method using tetrabutyl titanate and tetraethyl orthosilicate as titania and silica precursors. The as-prepared FTSC was characterized by powder X-ray diffraction, scanning electron microscope, transmission electron microscopy, energy dispersive X-ray spectroscopy and N2 adsorption–desorption isotherms. The results show that the FTSC possesses foam like structures with cavities and mesoporous shells, and the anatase-phase titania in FTSC was confirmed. The specific surface area of FTSC is 354 m2/g and the average pore diameter is about 7.6 nm. The obtained FTSC shows promising efficiency in the photocatalytic degradation of methylene blue under UV light.The foamed titania–silica composite (FTSC) possesses foam like structures with cavities and mesoporous shells. The photocatalytic activity evaluation shows that the FTSC exhibits better photocatalytic activity than commercial AEROXIDE TiO2 P25 powders.

•Super-microporous zeolite Fe–MFI was prepared via template method.•Potassium hexacyanoferrate as an iron source in the syntheses.•The iron ions incorporated onto the zeolite network in tetrahedral coordination.Zeolite Fe–MFI possessing super-micropores has been synthesized by a direct hydrothermal method using potassium hexacyanoferrate(III) as the iron source. The results show that the material has a highly crystalline MFI zeolite structure, displaying a regular structure with ca. 0.7–1.5 nm in pore diameter. X-ray absorption spectroscopy results indicated that the iron was present in the form of tetrahedrally coordinated Fe3+ ions incorporated on the zeolite network. The super-microporous Fe–MFI exhibited good catalytic performance in the hydroxylation of phenol by H2O2.Scanning electron microscope provided evidence that the synthesized Fe–MFI has a highly crystalline MFI structure. Nitrogen sorption isotherms of the sample showed the presence of super-micropores.

•The hierarchical hollow silica sphere supported TiO2 composite was synthesized.•The composite owned special hierarchical hollow sphere structure.•The composite showed enhanced photocatalytic activity.A novel hierarchical hollow silica sphere supported TiO2 composite material (TiO2/HHSS) was synthesized. The X-ray diffraction data show that the obtained TiO2/HHSS nanoparticles had a pure anatase phase. The SEM and TEM demonstrate that TiO2/HHSS was constructed by spherical particles with a diameter between 90 and 150 nm having a small-ball@big-ball structure. The shell of the big-ball was composed of small-balls (15–20 nm), and the small-balls were covered with an external wall. The TiO2/HHSS nanoparticles showed remarkable enhancement of photocatalytic activity in comparison with commercial P25. The positive effects of the hierarchical hollow sphere structure on the photocatalytic activity are discussed.The novel hierarchical hollow silica sphere supported TiO2 nanocomposite (TiO2/HHSS) has a small-ball@big-ball structure. The shell of the big-ball is composed of small-balls. The small-balls are covered with an external wall. The photocatalytic activity evaluation shows that TiO2/HHSS exhibits better photocatalytic activity than commercial Degussa P25 counterpart.

Hollow silica nanospheres (HSNS) with ultrasmall size distribution (∼20 nm) and hierarchical hollow silica spheres (HHSS) with shells composed of self-assembled HSNS have been successfully synthesized through a novel single-micelle-template approach by using CTAB as the template and octane as a swelling agent. The effect of the volume ratio of octane/water on the preparation of the hollow silica particles was investigated and the prepared samples were characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), dynamic light scattering (DLS) and nitrogen sorption analysis. The results demonstrated that the organic solvent octane can lead to the particles changing from conventional ordered mesostructures to individual HSNS (∼20 nm) and an increase in the octane/water ratio will bring about the self-assembly of the HSNS to form HHSS (90–150 nm). The HHSS can effectively load drug molecules for delivery.

Mesoporous silica pillared clay (SPC) incorporated with tungstophosphoric acid (HPW) has been synthesized via in situ introducing P and W source in the acidic suspension of the clay interlayer template during the formation of the silica pillared clay. The samples were characterized by XRD, XRF, FT-IR, TG-DTA, N2 adsorption–desorption, and SEM techniques. The results showed that the HPW formed by in situ method has been effectively introduced into the framework of mesoporous silica pillared clay and its Keggin structure remained perfectly after formation of the materials. In addition, samples with similar HPW loadings were also prepared by impregnation method using SPC as the support. HPW in the incorporated samples was better dispersed into the silica pillared clay than in the impregnated samples. The results of catalytic tests indicated that the encapsulated materials demonstrated better catalytic performance than the impregnated samples in oxidative desulfurization (ODS) of dibenzothiophene (DBT).Graphical abstractHighlights► The in situ method for encaging HPW into the framework of the mesoporous SPC. ► The formation mechanism of the HPW–SPC samples was described. ► HPW–SPC catalysts exhibited good thermostability and reusability. ► HPW–SPC samples showed better catalytic performance than HPW–SPC–IM samples.

The mesoporous ferrisilicates (MFS) with high iron content were synthesized by pH-modification method, and the iron content could be up to 10.5 wt.% (Si/Fe = 8). The pH was kept less than 2 at pre-hydrothermal synthesis step and was adjusted to 11 during hydrothermal step. The samples were characterized by XRD, HRTEM, N2-sorption, XRF, FTIR, DRUV–vis, Fe K-edge EXAFS, EPR, and DSC. The results suggested that the MFS materials were ordered 2D hexagonal mesophase of MCM-41, and the iron atoms were tetrahedral coordinated in the silica framework. This material could efficiently catalyze the hydroxylation of phenol in water medium using H2O2 as an oxidant, and the phenol conversion could be up to 52% under the optimal experimental conditions.Graphical abstractThe mesoporous ferrisilicates (MFS) with high iron content were synthesized by internal pH-modification method, and the Fe K-edge XAFS results indicate Fe3+ ions incorporate into the silicate framework with a tetrahedral coordination structure.Highlights► Mesoporous ferrisilicates with high content of iron were prepared via pH-modification method. ► The optimum limit of iron in the silicate framework could be up to 10.5 wt.% (Si/Fe = 8). ► The color of high iron content mesoporous ferrisilicate is white.

The ordered mesoporous MCM-41 materials incorporated with transition metal substituted polyoxometalate (PW11O39M1)5− (designated as M1–POM, M1 = Ni2+, Co2+ or Cu2+) were synthesized via an original direct synthesis method. The samples were characterized by XRF, XRD, FT-IR, HRTEM, SEM and N2 adsorption isotherm techniques. The results show that M1–POM was uniformly dispersed in the samples and its structure remained intact in the materials. The samples exhibited excellent catalytic performance for the esterification of n-butanol with acetic acid, which is better than that of the supported lacunary polyoxometalate (PW11O39)7− and the impregnated (IM) samples.Graphical abstractThe mesoporous MCM-41 materials were incorporated with transition metal substituted lacunary polyoxometalate by the direct synthesis method (DS) and the impregnation method (IM), respectively. Fig. A is 15%Ni–POM/MCM-41(DS), and Fig. B is 15%Ni–POM/MCM-41(IM).Highlights► M1–POM was encapsulated into MCM-41 via an original direct synthesized method. ► The M1–POM/MCM-41 has well-ordered mesopores and spherical morphology. ► The M1–POM/MCM-41 samples showed good performance on the esterification. ► The strong interactions of M1–POM with the support ensured little loss of M1–POM.

A series of Fe-MCM-41s with high iron content were synthesized using direct hydrothermal method under alkaline condition using tartaric acid as complexing reagent and cetyltrimethylammonium bromide (CTAB) as the structure-directing agent. The result samples were characterized by XRD, XRF, N2 adsorption–desorption, EPR, FT-IR, UV–vis and HRTEM techniques. The catalytic performance for the oxidative desulfurization (ODS) of DBT was also examined. The results indicated that the mesoporous structure did not collapse until the Fe content reached up to 13.21 wt.% and the iron species were mainly in the framework with tetrahedral coordination and no other species of Fe were detected in the 11.75 wt.% Fe-MCM-41 sample. The prepared samples possessed high specific surface area (1182–782 m2 g−1), big pore volume (1.18–2.86 cm3 g−1) and pore diameter (3.8 nm). The samples exhibited excellent catalytic performance for ODS of DBT by hydrogen peroxide at 50 °C and the sulfur removal did not decline after being recycled four times.Graphical abstractThe Fe-MCM-41s with high Fe content were synthesized using direct hydrothermal method and all the iron atoms were incorporated into the framework as Fe wt.% smaller than 11.75%.Highlights► Fe-MCM-41s with high Fe content were synthesized using direct hydrothermal method. ► All Fe atoms were incorporated into the framework with Fe wt.% smaller than 11.75%. ► The samples possessed high specific surface area, big pore volume and pore diameter. ► The samples exhibited excellent catalytic performance and reusability for ODS of DBT.

A method of incorporating iron onto the mesoporous silica network using potassium ferricyanide (K3Fe (CN)6) as the iron source was established. The Fe (CN)63 + ions interact with the template and attached onto the silica network after the as-synthesized sample calcined at 823 K. FT-IR spectroscopy provided a clear evidence for the interaction between cyanide ligands and template. XANES spectroscopic displayed that the Fe3 + changed from octahedral to tetrahedral coordinated during thermal treatment. XRD and HRTEM results indicated that the iron ions incorporated onto the silica network without destroying the lattice structure of the parent MCM-41. The synthesized material exhibited a good activity for phenol hydroxylation.Fe (CN)63 + ions interact with template and the iron species incorporated onto the network of mesoporous silica during the thermal treatment.Highlights► Mesoporous ferrisilicates (Fe-MCM-41) was prepared via post-synthesis method. ► Potassium ferricyanide (K3Fe (CN)6) was used as the iron source in the syntheses. ► The iron ions incorporated onto the silica network during thermal treatment.

Mesoporous silica pillared clay (SPC) materials with different contents of H3PW12O40 (HPW) heteropoly acid were synthesized by introducing HPW into clay interlayer template in an acidic suspension using sol–gel method. Samples with similar HPW loadings were also prepared by impregnation method using SPC as the support. The results of the characterizations showed that HPW was dispersed more homogeneously in the encapsulated samples than in the impregnated samples. The encapsulated materials exhibited better catalytic performance than the impregnated samples in oxidative desulfurization of dibenzothiophene-containing model oil. The sulfur removal reached up to 98.6% for the model oil under the experiential conditions.Graphical abstractA facile method was reported to prepare as-synthesized mesoporous silica pillared clay materials with HPW heteropoly acid encapsulated into the framework, which exhibited high and stable activity in deep oxidative desulfurization.Highlights► HPW heteropoly acid encapsulated into the mesoporous SPC. ► HPW was dispersed homogeneously in the HPW-SPC-SG samples. ► HPW-SPC-SG samples showed better catalytic performance than HPW-SPC-IM samples. ► HPW-SPC-SG catalysts exhibited good reusability.

The mesoporous silica pillared clay (SPC) incorporated with Keggin-type H3PW12O40 (HPW) heteropoly acid was prepared by introducing HPW into clay interlayer template in an acidic suspension using sol–gel method. The materials are readily separable mesoporous materials with high specific surface areas. The results indicate that the surfactants play a decisive role in the introduction of HPW molecule and the pore formation. Moreover, the surface area and pore size of the materials can be controlled by the molecular length and functional groups of the surfactants. The formation mechanism of the materials was also proposed. The synthesized materials exhibited good catalytic performance in oxidative desulfurization of dibenzothiophene-containing model oil. Under the best conditions, the sulfur removal can reach up to near 100%. The excellent catalytic performance for oxidative desulfurization opens up new opportunities for applications of the synthesized materials in catalysis.Graphical abstractHighlights► HPW heteropoly acid was encapsulated into the mesoporous sillica pillared clay. ► Surfactant have a significant impact in the formation of the gallery pore. ► The catalysts exhibit high catalytic activity in deep ODS of model oil. ► The catalysts exhibit good reusability.

The novel rich heteroatom-containing (15 wt.%) composite molecular sieves M1-MFI/M2-MCM-41 have been prepared from the ionic complex [(C4H9)4N]2+[M1(EDTA)]2− and [C16H33(CH3)3N]2+[M2(EDTA)]2− as the organic templates, which could effectively introduce a large amount of heteroatoms into the framework of molecular sieves. The products were characterized by XRD, XRF, SEM, HRTEM, N2 adsorption–desorption, H2-TPR, FT-IR, TG and DSC techniques. The catalytic performances of the composite materials were investigated by means of residual oil hydrocracking. Characterization results showed that the composite materials simultaneously possessed a typical orthogonal MFI phase and a hexagonal MCM-41 phase and the two phases were composite rather than the physical mixture. H2-TPR data indicated all of the heteroatoms were incorporated by isomorphous substitution of silicon in framework. N2 adsorption–desorption analysis exhibited that these samples possessed regular and stable structure with high specific surface area and large pore diameters of 550–620 m2 g−1, 3.5 nm and 5.5 nm, respectively. M1-MFI/M2-MCM-41 presented excellent activities in hydrocracking of residual oil, which were superior to the pure materials of MFI/MCM-41.The formation process of composite molecular sieves M1-MFI/M2-MCM-41 by using ionic complex [(C4H9)4N]2+[M1(EDTA)]2− and [C16H33(CH3)3N]2+[M2(EDTA)]2− as template.

A novel one-step synthesis route to ordered mesoporous silica-pillared clay (SPC) with cantonic−anionic mixed-gallery templates has been successfully established. This approach involves the type and formation of surfactant mixture for SPC through intragallery ammonia-catalyzed tetraethoxysilane (TEOS). The formation of a precursor with a micromesoporous framework is a result of TEOS hydrolysis and the presence of surfactant micelles in the gallery regions under ammonia-catalyzed conditions. The type of structure was confirmed by X-ray diffraction (XRD), differential scanning calorimetry (DSC), scanning electron microscopy (SEM), and low-temperature N2 physisorption. Addition of the anionic surfactant resulted in changes of the layered structure and ratio of micropores to mesopores. The formation mechanism of SPC derivatives is proposed.

A novel Ti-containing SBA-16-type mesoporous material (with various Ti loadings of 5, 10, and 15 wt%) was synthesized by an evaporation-induced self-assembly method using F127 copolymer as template. The materials were characterized by XRD, FTIR, TG–DTA, N2 adsorption, SEM, HRTEM, and XPS. The characterization results show that the material possesses high thermal stability, thick pore walls (10.43–10.68 nm), and high surface area (642.26–691.5 m2/g) with a mesoporous worm-like structure, and titanium was successfully incorporated into the silica matrix with a tetrahedral environment. The material showed high activity in the oxidative desulfurization of DBT and its activity was not reduced even after three times recycling; further reuse resulted in a gradual decrease in its activity.High-resolution TEM micrograph of Ti-containing SBA-16-type mesoporous material prepared by the evaporation-induced self-assembly method.

A novel mesoporous material (C19H42N)4H3(PW11O39)/SiO2 with different (C19H42N)4H3(PW11O39) loadings (6.3–19.4 wt.%) was prepared by direct sol–gel method. The material was characterized by XRD, FT-IR, Raman scattering spectroscopy, 31P CP-MAS NMR spectroscopy, XPS, XRF, N2 adsorption/desorption, DSC and HRTEM. The characterization results reveal that (C19H42N)4H3(PW11O39) was highly dispersed into silica matrix and its structure remained intact after formation of the material. The material possessed high surface area (543–1009 m2/g), pore volume (0.40–1.19 cm3/g), and pore walls thickness (5.85–9.37 nm) with interconnected worm-like mesostructure. Small angle XRD and N2 adsorption/desorption results show that the material retained its mesoporous structure for up to 14.9 wt.% (C19H42N)4H3(PW11O39) loading, further increase in percentage resulted in the formation of disordered structure with abundant micropores. The material was found to be highly active and reusable for oxidative desulfurization of bulky organosulfur compound DBT.

Hollow silica nanospheres (HSNS) with ultrasmall size distribution (∼20 nm) and hierarchical hollow silica spheres (HHSS) with shells composed of self-assembled HSNS have been successfully synthesized through a novel single-micelle-template approach by using CTAB as the template and octane as a swelling agent. The effect of the volume ratio of octane/water on the preparation of the hollow silica particles was investigated and the prepared samples were characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), dynamic light scattering (DLS) and nitrogen sorption analysis. The results demonstrated that the organic solvent octane can lead to the particles changing from conventional ordered mesostructures to individual HSNS (∼20 nm) and an increase in the octane/water ratio will bring about the self-assembly of the HSNS to form HHSS (90–150 nm). The HHSS can effectively load drug molecules for delivery.