A novel bioinspired approach for ordered mesoporous silica was developed on the basis of the synergic coassembly between polyamine and an anionic surfactant as a template. With the help of cationic polyamine, anionic surfactant micelles could be utilized as a mesostructure template, whereas with the aid of the anionic surfactant micelles the cationic polyamine chains underwent aggregation to exert their ability to induce silica condensation. Mesoporous silicas with well-ordered mesostructure of Fd-3m symmetry and 3D hexagonal close-packed mesostructure (hcp) were fabricated. Because of the abundant types of anionic surfactants and polyamines, the synthesis approach can be regarded as a general method for anionic-surfactant-templated mesoporous silica, and new mesostructures and morphologies are expected.

By using hierarchically mesoporous silica spheres as hard template, 2-aminopyridine and FeCl3 as carbon, nitrogen and iron sources, respectively, iron and nitrogen co-doped hierarchically mesoporous carbon spheres (Fe–N–CS) were successfully prepared. The sample Fe–N–CS-900 obtained at a carbonization temperature of 900 °C exhibited a highly efficient electrocatalytic activity with positive half-wave potential (−0.11 V), high limiting current density (−4.79 mA cm−2) and high selectivity (electron transfer number around 4) for the oxygen reduction reaction (ORR) in alkaline media. Moreover, Fe–N–CS-900 shows higher stability and better methanol tolerance in comparison to commercial Pt/C catalyst in both alkaline and acidic media. Its highly efficient ORR activity could be ascribed to its high specific surface area, unique porous structure and homogeneous distribution of Fe–Nx active sites formed during pyrolysis.

Oxygen reduction catalysts based on heteroatom-doped mesoporous carbon nanosheets loaded with highly crystalline FeP nanoparticles (FeP@FePNCs) were fabricated using a simple, one-step carbonization–phosphization methodology. The obtained FeP@FePNCs exhibited outstanding catalytic activity and durability towards the oxygen reduction reaction (ORR) in alkaline media. Moreover, the FeP@FePNCs also displayed high-performance in acidic media. The remarkable ORR activity originates from the synergetic effects between the embedded FeP nanoparticles and the heteroatom-doped carbon structures. Moreover, the porous structure, high specific surface area, and electron conductivity can contribute to enhance the ORR performance.

We report a facile two-step pyrolysis and acid leaching process to fabricate a high performance oxygen reduction reaction (ORR) electrocatalyst Fe2O3@Fe–N–C, which is composed of Fe–N-doped carbon foam nanosheets with embedded carbon coated Fe2O3 nanoparticles to enhance the ORR performance in acidic medium. The ORR activities of the Fe2O3@Fe–N–C electrocatalysts obtained at different pyrolysis temperatures are investigated and the catalyst fabricated by pyrolysis at 800 °C displays the optimal activity. A rotating disk electrode (RDE) study reveals that it exhibits a positive half-wave potential of 0.535 V (vs. Ag/AgCl), high selectivity (4e− process), excellent long-term stability (96.3% of the initial current remaining after 20 000 s of continuous operation) and good tolerance against the methanol-crossover effect in acidic medium, making it a promising candidate for substituting the commercial Pt/C catalyst in polymer electrolyte membrane fuel cells (PEMFCs). The remarkable ORR activity originates from the cooperative effect of carbon coated Fe2O3 nanocrystals and Fe–N-doped carbon foam nanosheets. Moreover, the porous structure, high specific surface area, and electron conductivity could contribute to the enhanced ORR performance.

PtSn2–SnO2/C nanocatalyst was prepared by co-reduction of Pt and Sn precursor at ca.15 °C. The formation of PtSn2–SnO2 nanoparticle was determined by XRD, TEM and XPS characterization. This PtSn2–SnO2/C nanocatalyst exhibits stronger resistance to CO poisoning and effectively improves methanol electro-catalytic effect, up to 3 times than the commercial Pt/C catalyst.The PtSn2–SnO2/C nanocatalyst synthesized by the co-reduction of Pt and Sn precursor at 15 °C expressed high activity to the methanol electro-oxidation, up to 3 times than the commercial Pt/C catalyst.Download full-size image

The Mg2+-assisted low temperature reduction approach was applied for the preparation of an alloyed AuPd/C nanocatalyst, which exhibited high activity in hydrogen generation from formic acid. At room temperature the initial turnover frequency (TOF) could reach as high as 1120 h−1.

Hierarchically porous Ti-SBA-2 with high framework Ti content (up to 5 wt%) was firstly synthesized by employing organic mesomorphous complexes of a cationic surfactant (CTAB) and an anionic polyelectrolyte (PAA) as templates. The material exhibited excellent performance in oxidative desulfurization of diesel fuel at low temperature (40 °C or 25 °C) due to the unique hierarchically porous structure and high framework Ti content.

•N-doped hierarchically porous carbon spheres were prepared by nanocasting method.•Methyl violet was used as carbon and nitrogen precursor with mesoporous silica as template.•The catalyst exhibited high performance in ORR.•The onset potential of the catalyst was very closer to that of Pt/C catalyst.Using hierarchically mesoporous silica spheres as a hard template and methyl violet as carbon and nitrogen source, nitrogen-doped hierarchically porous carbon spheres (N-HCS) are successfully prepared via a nanocasting method. The nitrogen-doped carbon spheres obtained after carbonization at 1000 °C (N-HCS-1000) exhibit a hierarchically micro-meso-macroporous structure with a relatively high surface area (BET) of 1413 m2 g−1 and a notably large pore volume of 2.96 cm3 g−1. In an oxygen reduction reaction (ORR) in alkaline media, the N-HCS-1000 material exhibits excellent activity with high current density, and its onset potential is notably close to that of the commercial Pt/C catalyst. The efficient catalytic activity of this catalyst could be attributed to the high electrical conductivity of the nitrogen-doped carbon matrix as well as the hierarchically porous framework. This catalyst also exhibits better methanol crossover resistance and higher stability than the commercial Pt/C catalyst.

•Homogeneously distributed iron carbides nanoparticles wrapped in carbon are embedded in nitrogen-doped porous carbon nanosheets.•The novel catalyst (Fe3C@N-C-900) exhibits highly efficient ORR activity in both acidic and alkaline media.•Fe3C@N-C-900 exhibits better methanol tolerance and higher stability than Pt/C catalyst.By simple thermal treatment of low-cost precursors (melamine, FeSO4 and 1, 10-phenanthroline) in inert atmosphere, nitrogen-doped porous carbon nanosheets with embedded iron carbide nanoparticles were prepared (denoted as Fe3C@N-C-T). The catalyst prepared at 900 °C (Fe3C@N-C-900) is composed of mesoporous nitrogen-doping carbon nanosheets and graphitized carbon covered iron carbide nanoparticles (10–20 nm), with relatively high specific area (705 m2 g−1). As non-precious metal catalyst, Fe3C@N-C-900 exhibits highly efficient electrocatalytic activity (half-wave potential of 0.806 V and kinetic limiting current density (ik) of 18.35 mA cm−2 at 0.7 V) for oxygen reduction reaction (ORR) in acidic media, through an efficient four-electron ORR process. In addition, Fe3C@N-C-900 also displays better methanol tolerance and higher stability (only 12.5% loss after 20,000 s) in comparison to commercial Pt/C catalyst.

Hierarchically mesoporous titanosilicate Ti-SBA-1 was synthesized with organic mesomorphous complexes of polyelectrolyte (poly(acrylic acid) (PAA)) and cationic surfactant (hexadecyl pyridinium chloride (CPC)) as template, tetraethylsiloxane as silica source and titanium ethoxide as titanium source. By adjusting the amount of titanium ethoxide in the synthesis, a series of Ti-SBA-1 particles with different Si/Ti ratio (79–180) were prepared. After incorporation of Ti into the silica framework the well-ordered cubic Pm3¯n mesostructure remained, as well as the morphology, particle size. UV–vis DR spectra of the Ti-SBA-1 materials indicated that incorporated titanium species existed in a highly dispersed state and exhibited tetrahedral and octahedral coordination in the silica framework.Mesoporous titanosilicate Ti-SBA-1 materials with hierarchical pore structure were successfully synthesized by employing organic mesomorphous complexes of polyelectrolyte (poly(acrylic acid) (PAA)) and cationic surfactant (hexadecyl pyridinium chloride (CPC)) as templates, tetraethylsiloxane and titanium ethoxide as silica source and titanium source, respectively.

•We report a novel one-pot co-reduction solvothermal approach to obtain concave and dendritic PtCux (x = 1, 2 and 3) bimetallic nanoparticles.•PtCu2/C shows exceptional catalytic activity and strong poisoning resistance in methanol oxidation.•The specific and mass activities of PtCu2/C were 4.1 and 3.3 times higher than those of the commercial Pt/C catalysts.PtCux (x = 1, 2 and 3) bimetallic nanocrystals with concave surface and dendritic morphology were prepared and used as electrocatalysts in methanol oxidation reaction (MOR) for polymer electrolyte membrane fuel cells. The bimetallic nanocrystals were synthesized via one-pot co-reduction of H2PtCl6 and Cu(acac)2 by oleylamine and polyvinyl pyrrolidone (PVP) in an autoclave at 180 °C. The concave dendritic bimetallic nanostructure consisted of a core rich in Cu and nanodendrites rich in Pt, which was formed via galvanic replacement of Cu by Pt. It was found that PVP played an important role in initiating, facilitating, and directing the replacement reaction. The electrochemical properties of the PtCux were characterized by cyclic voltammetry (CV) and chronoamperometry (CA). The concave dendritic PtCu2/C nanocrystals exhibited exceptionally high activity and strong poisoning resistance in MOR. At 0.75 V (vs. reversible hydrogen electrode, RHE) the mass activity and specific activity of PtCu2/C were 3.3 and 4.1 times higher than those of the commercial Pt/C catalysts, respectively. The enhanced catalytic activity could be attributed to the unique concave dendritic morphology of the bimetallic nanocrystals.

A facile one-step method to synthesize nanocrystalline Mn-based spinels AMn2O4 (A = Co, Zn, Cd) at room temperature was reported. The obtained well crystallized CoMn2O4 spinel nanoparticles exhibited high catalytic activity for ORR in alkaline media as electrocatalysts.

By reduction of mixed noble metal precursors in aqueous phase under ice-water bath conditions, well dispersed Au–Pd alloy nanoparticles supported on carbon black were facilely prepared. The catalyst exhibited high activity and selectivity at nearly 0 °C, with an initial turnover frequency (TOF) up to 635 h−1. At room temperature the initial TOF of the catalyst reached 1075 h−1, which is rather high compared with those reported in the literature.

Mesoporous single crystal-like Y2O3 nanocubes have been prepared through a coordination-based self-assembly process. Firstly, a uniform nanocube-like Y-lysine precursor was simply prepared with hydrothermal treatment. After the simple thermal treatment process, nanocube-shaped yttrium oxides with the morphology inherited from the Y-lysine precursor were successfully prepared. The phase, morphology, size and crystalline structure were well characterized by XRD, SEM and TEM. N2 adsorption–desorption demonstrates the mesoporous characteristics of the Y2O3 nanocubes, showing a relatively high surface area of 60 m2/g.Mesoporous single crystal-like Y2O3 nanocubes were fabricated through a coordination-based self-assemble process.

Pt:Pd:Co ternary alloy nanoparticles were synthesized by sodium borohydride reduction under nitrogen, and were supported on carbon black as catalysts for methanol and formic acid electro-oxidation. Compared with Pt0.65Co0.35/C, Pt/C, Pd0.65Co0.35/C, and Pd/C catalyst, Pt0.35Pd0.35Co0.30/C exhibited relatively high durability and strong poisoning resistance, and the Pt-mass activity was 3.6 times higher than that of Pt/C in methanol oxidation reaction. Meanwhile, the Pt0.35Pd0.35Co0.30/C exhibited excellent activity with higher current density and higher CO tolerance than that of Pt0.65Co0.35/C, Pt/C, Pd0.65Co0.35/C, and Pd/C in formic acid electro-oxidation.Pt0.35Pd0.35Co0.3/C was prepared as catalysts in methanol and formic acid electro-oxidation, and it exhibited higher catalytic activity and durability than Pt0.65Co0.35/C, Pd0.65Co0.35/C, Pt/C and Pd/C catalysts.

A novel bioinspired approach for ordered mesoporous silica was developed on the basis of the synergic coassembly between polyamine and an anionic surfactant as a template. With the help of cationic polyamine, anionic surfactant micelles could be utilized as a mesostructure template, whereas with the aid of the anionic surfactant micelles the cationic polyamine chains underwent aggregation to exert their ability to induce silica condensation. Mesoporous silicas with well-ordered mesostructure of Fd-3m symmetry and 3D hexagonal close-packed mesostructure (hcp) were fabricated. Because of the abundant types of anionic surfactants and polyamines, the synthesis approach can be regarded as a general method for anionic-surfactant-templated mesoporous silica, and new mesostructures and morphologies are expected.

Hierarchically mesoporous silica nanorods with well-ordered cubic Fm-3m mesostructure were fabricated for the first time under basic conditions by using cationic surfactant cetyltrimethylammonium bromide (CTAB) as a template with poly(acrylic acid) (PAA) and triblock copolymer Pluronic P123 (PEO20PPO70PEO20) as co-templates. Due to the electrostatic interaction between CTAB and PAA, they would co-assemble to form complex colloids. The nonionic surfactant P123 would also be incorporated into the complex. The CTA/PAA/P123 complex colloids exhibited the morphology of nanorods, and the morphology of the final product inherited from the complex. The ordered mesopores (∼3 nm) of hierarchically mesoporous silica were connected with the secondary mesopores, whose average pore size was about 20 nm. Interestingly, the existence of the secondary mesopores did not disturb the ordered mesostructure of the nanorods and thus all the nanorods remained as single-crystalline mesoporous silica crystals. By varying the average molecular weight of the triblock copolymers, we could obtain hierarchically mesoporous silica with 2-D hexagonal mesostructure, which had a high surface area (∼980 m2 g−1) and large pore volume (∼1.3 cm3 g−1). Au-supported hierarchically mesoporous silica nanorods exhibited much higher reaction rate than that of Au-supported MCM-41 in catalytic reduction of 4-nitrophenol, as a result of its unique hierarchically mesoporous structure.

Mesoporous silica nanoparticles are drawing increasing attention in biomedical applications. In this work, hierarchically nanoporous SBA-1 single-crystal-like nanoparticles, with a size of 50–300 nm, were synthesized using a cationic surfactant and anionic polymer poly(acrylic acid) (PAA) mesomorphous complexes as a template. The obtained mesoporous silica nanoparticles showed a well ordered cubic Pmn mesostructure, large pore volume and high BET surface area. The materials possess biomodal nanopores corresponding to well-ordered mesopores and secondary interstitial nanopores.

Ordered multi-amine functionalized mesoporous silica with a 3D cubic Fdm mesostructure was synthesized with anionic surfactant N-lauroylsarcosine sodium (Sar-Na) as a template, and [3-(2-aminoethyl)-aminopropyl]trimethoxysilane (DAPS) or 3-[2-(2-aminoethylamino)ethylamino]propyl-trimethoxysilane (TAPS) as co-structure directing agents (CSDAs). To our knowledge, this is the first time the use of DAPS and TAPS as CSDAs in an anionic surfactant templated system have been reported. Using DAPS and TAPS as the CSDA favors the formation of a 3D cubic mesocaged solid with Fdm symmetry, while with 3-aminopropyltriethoxysilane (APS) as the CSDA, only the p6mm mesoporous phase was formed. The geometrical change of the CSDA resulted in a change of the surfactant packing parameter, leading to the change of the silica mesophase from 2D-hexagonal p6mm to 3D cubic Fdm symmetry. After extraction of the templates, multi-amine-functionalized cubic Fdm mesoporous silicas were obtained. The multi-amine functionlized mesoporous silicas exhibit excellent properties in adsorption and removal of heavy metal ions in solution as well as the support of noble metal nanoparticles.

Mesoporous zeolite silicalite-1 and Al-ZSM-5 with intracrystalline mesopores were synthesized with polyelectrolyte–surfactant complex as the template. Complex colloids were first formed by self-assembly of the anionic polymer poly(acrylic acid) (PAA) and the cationic surfactant cetyltrimethylammonium bromide (CTAB) in basic solution. During the synthesis procedure, upon the addition of the silica source, microporous template (tetrapropylammonium hydroxide), and NaCl, these PAA/CTA complex colloids underwent dissociation and gave rise to the formation of hollow silica spheres with mesoporous shells templated by CTAB micelles and PAA domains as the core. Under hydrothermal treatment, the hollow silica spheres gradually merged together to form larger particles with the PAA domains embedded as the space occupant, which acted as a template for intracrystalline mesopores during the crystallization of the zeolite framework. Amphiphilic organosilane was used to enhance the connection between the PAA domain and the silica phase during the synthesis. After calcination, single crystal-like zeolite particles with intracrystalline mesopores of about 5–20 nm were obtained, as characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and N2 adsorption measurements. With the addition of an aluminum source in the synthesis, mesoporous zeolite Al-ZSM-5 with intracrystalline mesopores was also synthesized, and enhanced catalytic property was observed with mesoporous Al-ZSM-5 in acetalization of cyclohexanone with methanol.

Single-crystal-like, hierarchically nanoporous silica SBA-1 particles were successfully fabricated by employing organic mesomorphous complexes of polyelectrolyte (poly(acrylic acid) (PAA)) and cationic surfactant (hexadecylpyridinium chloride (CPC)) as templates. By adjusting the amount of PAA in the synthesis, a series of silica particles with well-defined morphologies and well-ordered cubic Pm3̅n mesostructure were obtained. Both the mesostructure and well-defined morphology of the silica particles inherited those of the corresponding PAA/CPC mesomorphous complexes. The materials possess bimodal nanopores corresponding to the mesopore size of SBA-1 templated by surfactant micelles and secondary interstitial nanopores templated by phase-separated PAA with different domain sizes, respectively. Notably, the presence of a large amount of foamlike secondary nanopores did not disturb the single-crystal characteristic of the SBA-1 particles. By means of pore-expanding with 1,3,5-trimethylbenzene, the mesopore size of the SBA-1 could be easily tuned from 3.0 nm to 5.0 nm, and the secondary nanopore were enlarged to several hundreds of nanometers, while the morphology of the particles was not changed. Besides, using bridged organosilane as a precursor, a series of hierarchically nanoporous periodic mesoporous organosilicas (H-PMO) with well-defined morphology were fabricated. Because of the hierarchically nanoporous structure and inherent hydrophobic bridged-ethylene group, the H-PMO exhibited rapid adsorption rate and high adsorption capacity in enzyme and protein immobilization.Keywords: mesomorphous; nanoporous; periodic mesoporous organosilicas; polyelectrolyte; single-crystal-like; surfactant;

Bismuth–asparagine coordination polymer nanostructures with diverse morphologies were fabricated by a facile aqueous bottom-up coordination-based self-assembly approach, and they exhibited unique properties in catalysis and biological aspects.

A facile one-pot method was reported to fabricate noble metal nanoparticles encapsulated in silica hollow nanospheres with radially oriented mesopores, and the anionic amino acid surfactant, N-lauroylsarcosine sodium, played multiple roles: reducing agent, stabilizer, emulsion droplets and mesopore template.

Porous lanthanide oxides were fabricated by a precursor-thermolysis method. The precursors were synthesized by a hydrothermal reaction with lanthanide (La, Ce, Pr and Nd) salts, sodium oxalate and asparagine (or glutamine). Under hydrothermal conditions asparagine and glutamine exhibited greatly different complexation abilities with lanthanide cations. The competitive interactions of lanthanide cations with oxalate anions and asparagine (or glutamine) gave rise to the formation of precursors with different structures and morphologies. ESI-MS detection further confirmed the different complexation abilities of asparagine or glutamine with lanthanide cations at the molecular level. Variation of oxalate anion concentration or the pH value of the reaction solution could tune the morphology of the products. After calcination, porous lanthanide oxides were obtained with the morphologies of their corresponding precursors. Our work suggests that the complexation ability of organic molecules with metal cations could be a crucial factor for morphological control of the precursors. Moreover, considering the diversity of organic additives and metal salts, other metal oxides with complex composition and morphology could be fabricated via this organic molecule-modified precursor method.

Using anionic surfactant as templates, ordered mesoporous silica hollow spheres (MSHSs) with radially oriented mesochannels were synthesized with the aid of ultrasonic irradiation. The product was consisted of intact and dispersed hollow spheres with the diameter mostly in the range of 100−500 nm. The hollow spheres possessed uniform shell with the thickness of 35−40 nm, and the shell with radially oriented mesopores exhibited well-ordered structure as confirmed by X-ray diffraction (XRD) and transmission electron microscopy (TEM) measurements. After extraction of the anionic surfactant templates by solvent, silica hollow spheres with ordered and radially oriented amino-functionalized mesochannels were obtained. Moreover, by adjustment of the sonochemical processing time, the shell thickness, mesostructure (hexagonal, radial, or disordered), and shape of the inner cavity (hexagonal or spherical shape) of the hollow spheres could be facilely tuned. The formation process of the radially ordered mesostructure could be attributed to a relatively slow cooperative realignment process of the silica/surfactant hybrid mesophase in this anionic surfactant templating system. The effectiveness of the radially aligned mesopores was validated by a drug (flurbiprofen) release experiment, in which the hollow spheres exhibited relatively high drug storage capacity (>1000 mg g−1) and much faster drug release rate than that of the flakelike mesoporous SBA-15 particles.

A facile method to prepare Pd/organoclay catalysts was reported. At room temperature, in H2PdCl4 solution the quaternary ammonium surfactant modifiers intercalated in the organoclay adsorbed PdCl42− specifically and quickly. After reduction at room temperature, Pd nanoparticles were formed and well-dispersed in the organoclay matrix. The Pd/organoclay catalysts were used in aerobic oxidation of benzyl alcohol to benzaldehyde and exhibited high and stable activity. Particularly, the 0.2 wt% Pd/organoclay gave a remarkably high turnover frequency (up to 6813 h−1) under base- and solvent-free conditions. Our method can be generally applied for the preparation of Ru, Au and Pt/organoclay catalysts.

A series of lanthanideoxide microspheres and hollow spheres have been fabricated by thermolysis of corresponding lanthanide coordination compounds formed via bottom-up self-assembly.

3D flower-like (NH4)0.83Na0.43V4O10·0.26H2O vanadium bronze nano-platelet clusters are prepared via a facile hydrothermal method. The thickness of the nano-platelet is around 50 nm and the length ranged up to several micrometers. When used as positive electrode in rechargeable lithium battery, this material exhibits good cycle stability at different discharge rates (0.18–0.67C rate) and voltage limits (1.5–3.4 V and 2.0–3.4 V). The improvement the electrochemical properties of the (NH4)0.83Na0.43V4O10·0.26H2O might be attributed to the change of the lattice parameters due to the co-intercalation of the superstoichiometric cations (Na+ and NH4+).

In the synthesis of anionic-surfactant-templated mesoporous silica (AMS), the effects of alcohols have been investigated for the first time. Without the addition of extra alcohols, spherical mesoporous silica with radially oriented mesopores could be obtained through the anionic surfactant templating route. By using alcohols with different carbon chain length such as ethanol, n-butanol, hexanol and 1-octanol as the additives, different morphologies and mesostructures of mesoporous silica were obtained. It was found that both the types and concentrations of alcohols in the synthesis solution could tune the morphologies and mesostructures of the AMS, giving rise to the formation of hexagonal mesoporous discs and particles with novel multi-layered inner structure. In general alcohol with appropriate carbon chain length such as n-butanol and hexanol could act as the co-surfactant in the synthesis of mesoporous silica templated by anionic surfactant.In the synthesis of anionic-surfactant-templated mesoporous silica (AMS), the effects of alcohol have been investigated and the morphologies and mesostructures of AMS can be tuned by addition of alcohols.

Rose-like crystalline particles of ammonium vanadium sulfate hydroxide (NH4V3(OH)6(SO4)2) were synthesized by a solvothermal route using dimethyl sulfoxide (DMSO)–water as the solvent. Following a thermal decomposition process, rose-like V2O5 micro-architectures were fabricated via the in situ generated single-crystalline nanoparticles. When used as the cathode material in lithium-ion batteries, the rose-like V2O5 micro-architecture exhibited high initial discharge capacity. Sphere-like precursor was also prepared via selecting suitable carboxylic acid. This facile synthesis method would be used to prepare various vanadium oxides with different morphologies as well as other compounds.

Hierarchically structured mesoporous MnO2 with high surface area was prepared by a facile precursor route. Well-defined morphological manganese oxalate, synthesized by adding l-lysine via a hydrothermal method, was used as precursor. Mesoporous amorphous MnO2 with high Brunauer–Emmett–Teller (BET) surface area (340 m2/g) and mesoporous Mn2O3 composed of nano-crystals (BET surface area 188 m2/g) were obtained by selective calcination of the oxalate precursor at 330 °C and 400 °C, respectively. Thermogravimetric and differential thermal analyses (TG–DTA), X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), N2-sorption analysis and X-ray photoelectron spectroscopy (XPS) were used to characterize the structure and property of products. Cyclic voltammetry (CV) and charge–discharge measurements were used to preliminarily study the electrochemical performance of the products. The range of pH value (about 5.0–7.0) in the synthesis process is apt to prepare the hierarchical structured manganese dioxide. Other types of amino acids were also employed as the crystallization modifiers and different morphologies of manganese dioxides were obtained.

Silica particles with lamellar and wormhole-like bi-modal mesopores have been synthesized using anionic surfactant (N-lauroylsarcosine sodium) as the template. The particles with diameters of 300–500 nm possess bi-modal mesopores with pore sizes of 3 nm and 12 nm, which were ascribed to the disordered wormhole-like mesophase and lamellar mesophase, respectively. The BET surface area of the particles was 536 m2/g and the pore volume was 0.83 cm3/g. The lamellar mesophase and cylindrical mesophase were formed due to the co-assembly of the anionic surfactant and its protonized polar oil.

Mesoporous silica nano-spheres with pore size larger than 3 nm were synthesized using an anionic surfactant as the template. These nano-spheres possess centrosymmetric radial mesopores (emanating from the spherical center to the exterior surface) and form stable suspension. The spherical size and mesostructure can be finely tuned by changing the pH value of the synthetic system in the range of 8.8 to 6.4. In addition, when the pH value was decreased to 5.8, instead of spheres, anisotropic morphologies such as elliptical, peanutlike and trifurcate particles were obtained, exhibiting core/shell structure due to the different orientations of the mesopores in the core and the shell of the particles. It is proposed that the evolution of the morphologies and mesostructures of the products templated by anionic surfactants strongly depend on the pH value of the synthetic system.Mesostructured silica nano-spheres with centrosymmetric radial mesopores (emanating from the spherical center to the exterior surface), have been templated using an anionic surfactant.

Silica biominerals with elaborate skeletons can be fabricated at mild conditions of near-neutral pH and low temperature through biosilicification. In this paper, a biomimetic way was reported by which hexagonally ordered mesoporous silica fibers were facilely synthesized. Scanning electron microscope (SEM) and transmission electron microscope (TEM) observations reveal high yield of the mesoporous silica fibers with diameter varying from 200 to 400 nm and mesopore channels parallel to the axes of the fibers. At near-neutral pH, low temperature of 283 K was proved to be essential to control the morphogenesis of the surfactant liquid crystal templated silica. X-ray diffraction (XRD) and nitrogen sorption measurements indicate that the silica nanofibers possess ordered hexagonal mesostructure and narrow pore size distribution. Both the structure and morphology are sensitive to the synthesis temperature. Synthesis at the temperature of 293 K led to decreasing of mesostructure regularity, as well as a transformation of morphology from nanofibers to particle aggregates.

Hollow V2O5 microspheres consisting of closely packed particles, radially aligned rods and randomly packed platelets were fabricated via calcining the as-synthesized precursors prepared by a solvo-thermal route using NH4VO3 and oxalic acid as reagent and THF as solvent. SEM, TEM, XRD, XPS and UV–vis diffuse reflectance were used to characterize the fabricated materials. The results showed that THF and oxalic acid had a great influence on the morphologies and crystalline phases of the as-synthesized precursors. The photocatalysis measurements showed that hollow V2O5 microspheres consisting of randomly packed platelets exhibited the highest activity for degrading rhodamine B under UV light, and this might be ascribed to enhanced UV light absorbance.

Anionic polypeptide, the poly(sodium L-glutamate), was applied to fabricate microporous silica hollow nanospheres templated by the secondary structures of the polypeptide as porogens. In the synthesis, 3-aminopropyltrimethoxysilane (APMS) and tetraethyl orthosilicate (TEOS) were used as the silica sources, and the coassembly followed the mechanism of the anionic surfactant-templated mesoporous silica (AMS) through a S–N+-I– pathway, where S indicates the anionic polypeptide, I indicates inorganic precursors (TEOS), and N indicates costructure-directing agent (APMS), which interacted with the negatively charged anionic polypeptide secondary structures electrostatically and cocondensed with silica source to form the silica framework. The product was subjected to characterizations of X-ray diffraction (XRD), infrared (IR) spectroscopy, thermogravimetric (TG) analysis, scanning electron microscopy (SEM), transmitted electron microscopy (TEM), and nitrogen adsorption-desorption measurement. It was found that the pH value of the synthesis solution was an important factor to the morphological control of the silica products. Besides the microporous hollow nanospheres, microporous submicron silica solid and hollow spheres were also obtained facilely by changing the synthesis parameters. Our study further implied that anionic polypeptides, which were able to control mineralization of calcium carbonate and calcium phosphate, could also induce silica condensation in the presence of proper silica precursors. It was also expected that functional calcium carbonate (phosphate)/silica-nanocomposite materials would be fabricated under the control of the anionic polypeptide.

Manganese dioxides with various morphologies were prepared using a common hydrothermalmethod without any templates or additives. The evolution of the morphology was accompanied by the gradual conversion of the polymorphic forms from γ-type to β-type. Meanwhile, MnO2 microspheres, urchin-like nanostructures and nanowires were successfully synthesized. The products were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscope and transmission electron microscope. The evolution process can be explained by the Ostwald Ripening mechanism.

A facile and template-free approach was used to synthesize borated meso-macroporous TiO2 via adding TBT to boric solution following calcination. Borated mesoporous TiO2 solid sphere was obtained via adding the mixture of TBT and n-butanol under identical condition. Both borated meso-macroporous and mesoporous spherical TiO2 are of anatase, as proved by the XRD measurements. FT-IR and XPS results showed that boron might be incorporated in the TiO2 with the formation of B–O–Ti bonds. SEM results indicate macroporous and spherical structure with a diameter of ca. 3 μm. TEM and N2 adsorption verified the existence of mesopore. The average pore sizes and BET surface areas are 3.1 nm, 5.7 nm and 148 m2/g, 64 m2/g for borated meso-macroporous and mesoporous spherical TiO2, respectively. Both materials showed good photocatalytic activity for degrading rhodamine B (RhB) under exposure to UV light. Borated mesoporous TiO2 sphere showed higher photocatalytic activity than commercial photocatalyst P25.

Using organic salt Na2EDTA as trifunctional controller, hollow silica tubes with mesoporous wall were synthesized at circumneutral pH and low temperature. XRD, N2 sorption measurements, FTIR, TG-DTA, 29Si MAS NMR, SEM and TEM were performed to characterize the topology and morphology of mesoporous silica. The material exhibits disordered wormlike mesoporous structure with thick pore wall (estimated to be about 3 nm). The diameter of silica tubes ranges from 1 to 5 μm with the wall thickness of about 100–200 nm. Na2EDTA plays ternary roles in the synthesis: (1) as catalyst for hydrolysis and condensation of TEOS at circumneutral pH and low temperature; (2) to co-assemble with micelles of CTAB to give rise to wormlike mesoporous structure and (3) the incipient crystallization of Na2EDTA as template to induce formation of tubular morphology. The addition of ethanol to the synthesis system benefits the formation of silica tubules.

PbS crystals were synthesized by a simple hydrothermal process with l-lysine as the crystal growth modifier. Depending on the initial pH value of the reaction solution, the morphologies of the PbS crystals varied and the crystals with shapes of truncated nanocube, star-shaped dendrite, comb-like dendrite were obtained. The morphological evolution of the PbS crystals was explained by the different state of the ionization equilibrium of l-lysine in the solution at different pH values. The presence of differently charged l-lysine molecules would influence the crystal growth rates along different directions and result in the final morphologies of PbS crystals. It is proposed that when amino acids are used as crystal growth modifiers, besides the types of amino acids, which have been regarded to influence the crystals' growth, the ionized state of the amino acids at different pH values would play an important role in the morphological control, and this point may have been neglected before.

Helical MCM-41 hollow fiber with circular inner cavity, helical mesoporous channels and twisted hexagonal outer contour was observed for the first time. The hollow fiber wall is supposed to be composed of layers of helical meso-channels winding around the fiber axis. Furthermore, the helical pitches of these meso-channels may increase gradually depending on their winding radii, giving rise to zigzag fringes along the fiber axis in TEM micrographs. The growth of helical hollow fibers may start from a circular hollow fiber, and be followed by side growth of layers of helical meso-channels with varying pitches from inner side to outer side of the fiber.

Recently, ordered chiral mesoporous silica with a twisted hexagonal rod-like morphology and hexagonally ordered chiral channels has been synthesized by using chiral anionic surfactants as a liquid crystal template (S. Che, Z. Liu, T. Ohsuna, K. Sakamoto, O. Terasaki and T. Tatsumi, Nature, 2004, 429, 281). In this work, we report an observation of hierarchically helical mesoporous silica nanofibers organized by the achiral cationic surfactant cetyltrimethylammonium bromide (CTAB). These nanofibers (diameter ranging around 100–300 nm) grew from a two-phase system (H2O, CTAB, HCl for the aqueous phase and tetraethylsiloxane (TEOS) in hexane for the oil phase). SEM and TEM characterizations were performed and the results indicate that these nanofibers possess rope-like twisted hexagonal morphology and helical (chiral) mesoporous channels running inside winding around the fiber axis. These twisted hexagonal nanofibers could further curve spirally to form a second-level helical morphology (hierarchically helical morphology). As no chiral molecules are used in the synthesis, the hierarchically helical morphology of nanofibers could be explained by the different kinds of topological defects existing in the silicate liquid crystal seeds formed in a diffusion-controlled kinetic process, and these defects could initiate and direct the growth of particular forms of mesostructured silica. Formation of the ordered chiral mesorporous silica would be expected to be a general phenomenon in the cooperative assembly between amphiphilic organic molecules (templates) and inorganic species, no matter whether the templates are chiral or achiral.

Hierarchically structured silica was synthesized at near-neutral pH and under ambient conditions, utilizing synthetic polypeptide-based triblock copolymer poly(l-phenylalanine)-b-poly(ethylene glycol)-b-poly(l-phenylalanine) (Phe7–PEG135–Phe7) as a template. In the synthesis procedure, anilino-methyl triethoxy silane (AMTS) was used as an intermedium, i.e., on one hand it interacts with polypeptide-based triblock copolymer through π–π interaction between the phenyl groups of Phe segments and AMTS; on the other hand, AMTS can co-condense with tetraethoxylsilane (TEOS) through hydrolysis process. The prepared silica possesses mesoscale short-range-order and exhibits hierarchical structure with both supermicropores and interconnected layers of macropores. It is proposed that the supermicropores are templated by the polypeptide segments, while the open 3D interconnected macroporous networks are presumably ascribed to both PEG segments and organic solvent. It is proved that both polypeptide-based block copolymer and AMTS play important roles in the formation of mesoscale short-range-order and hierarchical structure.

27Al MAS and MQ MAS NMR spectroscopy were used to study the aluminum coordination in dealuminated mordenite. A 27Al MAS NMR signal ascribed to distorted tetrahedrally coordinated Al (DTetrAl) was detected. By comparison with amorphous silica–alumina and alumina materials, in which no such signal was seen, the presence of DTetrAl species could be a typical feature in crystalline zeolites after activation and dealumination. An ammonium–water solution treatment under pressure in an autoclave was introduced; besides realumination of the activated zeolite, this treatment can transform six- and five- coordinate Al species to a tetrahedral coordination state, both in dealuminated zeolites and in amorphous silica–alumina, but not in alumina. From these experimental results we suggest that: (i) amorphous silica–alumina is a better model for the extra-framework material in dealuminated zeolites than alumina; (ii) DTetrAl species, which are absent in thermally treated amorphous silica–alumina, might be regarded as transitional from the crystalline framework lattice state to the amorphous silica–alumina state during the process of dealumination.

Quaternary ammonium surfactants were generally used as templates in the synthesis of mesoporous materials, and the surfactants were removed by extraction or calcination to give the space of mesopores. Here with the cetyltrimethylammonium bromide templated mesostructured materials, we directly utilized the surfactants as capturing and stabilizing agents to prepare supported noble metal nanoparticle catalysts. The Pd-supported catalysts exhibited high and stable activity in hydrogenation of allyl alcohol (with a remarkably high turnover frequency of 5676 h−1) and aerobic oxidation of benzyl alcohol. During the recycle use of the catalyst, though surfactants were gradually leached into the reaction medium, the amount of Pd in the catalyst remained constant within experimental error. It is facile and energy-saving to use directly the as-synthesized mesostructured materials as support for noble metal nanoparticles without further calcination or further modification treatment. This method is versatile to prepare other noble metal (such as Au and Pt) supported catalysts by altering the metal precursors.A facile method was reported to prepare as-synthesized mesostructured material supported Pd catalysts which exhibited high and stable activity in hydrogenation of allyl alcohol.Download high-res image (96KB)Download full-size image

Hierarchically porous Ti-SBA-2 with high framework Ti content (up to 5 wt%) was firstly synthesized by employing organic mesomorphous complexes of a cationic surfactant (CTAB) and an anionic polyelectrolyte (PAA) as templates. The material exhibited excellent performance in oxidative desulfurization of diesel fuel at low temperature (40 °C or 25 °C) due to the unique hierarchically porous structure and high framework Ti content.

Porous lanthanide oxides were fabricated by a precursor-thermolysis method. The precursors were synthesized by a hydrothermal reaction with lanthanide (La, Ce, Pr and Nd) salts, sodium oxalate and asparagine (or glutamine). Under hydrothermal conditions asparagine and glutamine exhibited greatly different complexation abilities with lanthanide cations. The competitive interactions of lanthanide cations with oxalate anions and asparagine (or glutamine) gave rise to the formation of precursors with different structures and morphologies. ESI-MS detection further confirmed the different complexation abilities of asparagine or glutamine with lanthanide cations at the molecular level. Variation of oxalate anion concentration or the pH value of the reaction solution could tune the morphology of the products. After calcination, porous lanthanide oxides were obtained with the morphologies of their corresponding precursors. Our work suggests that the complexation ability of organic molecules with metal cations could be a crucial factor for morphological control of the precursors. Moreover, considering the diversity of organic additives and metal salts, other metal oxides with complex composition and morphology could be fabricated via this organic molecule-modified precursor method.

Hierarchically mesoporous silica nanorods with well-ordered cubic Fm-3m mesostructure were fabricated for the first time under basic conditions by using cationic surfactant cetyltrimethylammonium bromide (CTAB) as a template with poly(acrylic acid) (PAA) and triblock copolymer Pluronic P123 (PEO20PPO70PEO20) as co-templates. Due to the electrostatic interaction between CTAB and PAA, they would co-assemble to form complex colloids. The nonionic surfactant P123 would also be incorporated into the complex. The CTA/PAA/P123 complex colloids exhibited the morphology of nanorods, and the morphology of the final product inherited from the complex. The ordered mesopores (∼3 nm) of hierarchically mesoporous silica were connected with the secondary mesopores, whose average pore size was about 20 nm. Interestingly, the existence of the secondary mesopores did not disturb the ordered mesostructure of the nanorods and thus all the nanorods remained as single-crystalline mesoporous silica crystals. By varying the average molecular weight of the triblock copolymers, we could obtain hierarchically mesoporous silica with 2-D hexagonal mesostructure, which had a high surface area (∼980 m2 g−1) and large pore volume (∼1.3 cm3 g−1). Au-supported hierarchically mesoporous silica nanorods exhibited much higher reaction rate than that of Au-supported MCM-41 in catalytic reduction of 4-nitrophenol, as a result of its unique hierarchically mesoporous structure.

A facile one-pot method was reported to fabricate noble metal nanoparticles encapsulated in silica hollow nanospheres with radially oriented mesopores, and the anionic amino acid surfactant, N-lauroylsarcosine sodium, played multiple roles: reducing agent, stabilizer, emulsion droplets and mesopore template.

Bismuth–asparagine coordination polymer nanostructures with diverse morphologies were fabricated by a facile aqueous bottom-up coordination-based self-assembly approach, and they exhibited unique properties in catalysis and biological aspects.

The Mg2+-assisted low temperature reduction approach was applied for the preparation of an alloyed AuPd/C nanocatalyst, which exhibited high activity in hydrogen generation from formic acid. At room temperature the initial turnover frequency (TOF) could reach as high as 1120 h−1.

A series of lanthanideoxide microspheres and hollow spheres have been fabricated by thermolysis of corresponding lanthanide coordination compounds formed via bottom-up self-assembly.