The mass production of graphene and nitrogen-doped (N-doped) graphene constitutes one of the main obstacles for the application of these materials. We demonstrate a novel resin-based methodology for large-scale self-assembly of the N-doped graphene. The N-doped graphene is readily obtained by using a precursor containing nitrogen and metal ions. The N-doped graphene is characterized by Raman, AFM, TEM, SEM, synchronic radiation and XPS measurements. The electrochemical performance of the catalyst made with such materials is investigated by a rotating ring-disk electrode (RRDE) system. The results reveal that the N-doped graphene is a selective catalyst and possesses an outstanding electrocatalytic activity, long-term stability, and good methanol and CO tolerance for oxygen reduction reaction (ORR).

Water-dispersible 8-hydroxy-1,3,6-pyrene trisulfonic acid trisodium salt (PyS)-functionalized graphene (PyS-graphene) sheets were prepared by a π–π interaction method, in which the aromatic organic molecules of PyS were reacted with graphene. The PyS-graphene sheets were used as Pt nanoparticle support to prepare a Pt/PyS-graphene catalyst for direct methanol fuel cells. The prepared materials were characterized by ultraviolet spectrometry (UV–vis), Fourier transform infrared spectrometry (FT-IR), atomic force microscopy (AFM), X-ray diffraction (XRD), Raman spectroscopy (SERS), and transmission electron microscopy (TEM). The electrocatalytic properties of the catalysts for methanol oxidation were evaluated by cyclic voltammetry (CV). The Pt/PyS-graphene catalysts were found to have higher electrocatalytic activity for methanol oxidation than Pt/graphene catalyst. This finding can be attributed to the introduction of negative sulfonic (SO3−) groups to the graphene sheet surface, which makes the graphene sheets dispersible in water. Consequently, the Pt nanoparticles were uniformly and securely deposited onto the graphene sheet surface. These results suggested that the sulfonic group-modified water-dispersible graphene sheets can be used to improve the electrocatalytic activity of catalysts for fuel cells.

We report the molecular self-assembly of two amphiphilic peptides (A6K and V6K) and the application of their self-assemblies as organic templates to direct biosilica formation. Under ambient conditions, A6K self-assembled into nanotubes 2.7 nm tall and approximately 1 μm to 2 μm long. In contrast, V6K self-assembled into lamellar-stack nanostructures approximately 4 nm tall and under 100 nm long. The self-assembled peptide nanostructures were used as organic templates to direct biosilica formation. Comparing with the self-assembled structures formed by the peptide/anions system, novel silica morphologies can be obtained by changing the peptide composition, using different anions, and applying electrostatic/flow fields. We observed that the presence of anions is important but not enough to produce ordered silica structures with novel morphologies. This study provides further understanding of silica biomineralization tailored by assembled peptides, which offers a simple but efficient method to control the formation of inorganic material.

Molecular self-assembly has evolved into a robust and powerful bottom-up approach for constructing biomaterials. In this paper, we report the molecular self-assembly of synthetic short amphiphilic peptides (Ac-I3K-NH2, Ac-A3K-NH2, and Ac-A9K-NH2) and their applications as specific biomineralization templates to investigate mechanisms controlling biosilica morphologies. In pure water, variation of peptide compositions from Ac-I3K-NH2 to Ac-A3K-NH2 and Ac-A9K-NH2 resulted in altered self-assembly into nanotubes, lamellar stack nanostructures, and nanofibrils, respectively. Addition of phosphate ions did not result in noticeable morphological variation in the self-assembled nanostructures of Ac-I3K-NH2 and Ac-A3K-NH2, but favored growth of the Ac-A9K-NH2 peptide to form long nanofibrils, suggesting that phosphate ions tune peptide aggregation via different mechanisms. The self-assembled nanomaterials were then utilized as organic templates to direct biosilica formation. Our results indicate that the nature of the peptide/anion complex and external forces were important factors in producing ordered biosilica structures. Because of the exceptional stability of Ac-I3K-NH2 self-assemblies, silica intermediates tended to precipitate directly at the peptide surface, whereas Ac-A3K-NH2 and Ac-A9K-NH2 self-assemblies mediated re-assembly of large sizes of biosilica particles from twinned crystals. Our findings demonstrate the potential use of self-assembled templates and biomimetic conditions for controlling morphologies of inorganic materials.

A bioinspired approach to the synthesis of silica was induced by poly (L-lysine) (PLL) under the presence of a flow dynamic field. We found that the biosilica-like morphologies were controlled by the combination of the molecular weight of PLL and the condition of the hydrodynamic field. The flow dynamic field can provide extra energy to the silica nucleation system and produce new stereostructures of silica. This study established an easy and efficient approach for producing desired biosilica-like structures using an external force field via careful control of the reaction microenvironment.

In this paper, the formation of stable and continuous inorganic coating on indium tin oxide (ITO) via biosilica polymerization in the presence and absence of externally imposed electrostatic fields is described. The electrostatic fields exert a stronger influence on poly-L-lysines (PLLs) with a lower molecular weight than on larger ones. The larger peptides only enhance the density and uniformity of the biosilica deposition, whereas the overall biosilica morphology is observed to shift from sphere- to club-like structures when smaller PLLs are used. To explore the biosilica formation mechanism under precisely controlled electrostatic fields, scanning electron microscopy, circular dichroism, and atomic force microscopy were used to investigate the process of polypeptide tailored silica precipitation. Our results indicated that electric fields result in a high concentration of polypeptide near the ITO surfaces, which can be used as organic templates and basic building blocks to provide opportunities for tailoring material morphologies.

Hollow carbon spheres were synthesized using sulfonated polystyrene (PS) spheres as a core template and aniline monomer as carbon source. The spheres prepared were characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, Fourier infrared spectrometry, and thermogravimetry. The results showed that the as-prepared hollow carbon spheres were uniform in diameter with a shell thickness of 35 nm. The morphology, diameter, and wall thickness of the hollow carbon spheres can be tuned by varying the sulfonation rate of the PS core template. Sulfonation modification of PS spheres for 8 h was appropriate to prepare hollow carbon spheres. Owing to the presence of enough sulfonic acid groups on PS surface, the difference in the decomposition temperature between the PANI shells and the PS core was increased, resulting in the formation of the hollow carbon spheres with good sphericity and thick carbon shells by carbonizing sulfonated PS/PANI core-shell polymer spheres.

Biohydrogen was produced from starch in wastewater by anaerobic fermentation. The effects of parameters, such as pH, starch concentration were investigated and optimum operating conditions were determined. The optimal pH and starch concentration for hydrogen production at 37 °C were 6.5 and 5 g/L, respectively with a maximum hydrogen yield of 186 ml/g-starch. The produced biogas contains 99% of hydrogen after passing through KOH solution to remove CO2. The anaerobic fermentation installation was integrated with a proton-exchange-membrane fuel cell (PEMFC) system for on-line electricity generation. This combination system of biohydrogen and fuel cell achieved a power output of 0.428 W at 0.65 V per cell.

The Pt supported on WC modified MWCNT catalysts (PtWC/MWCNT) were synthesized by the combination of organic colloidal and intermittent microwave heating (IMH) methods for the first. The results proved the better performance of the PtWC/MWCNT catalyst than that of Pt/C for methanol oxidation in terms of the onset potential and peak current density. The synergistic effect between Pt nanoparticles and WC and the structure effect of the MWCNTs could be the reasons to result in the high activity. The CO stripping test provided the evidence that the onset potential shift for methanol oxidation is consistent with the reduction in the overpotential for the CO oxidation on PtWC/MWCNT catalyst. Therefore, the mechanism of the high performance for methanol oxidation on PtWC/MWCNT catalyst is probably the easier oxidation of CO-like species which cause high overpotential for further oxidation of methanol.

TiO2–SiO2 metal oxide materials with a mesostructure have been prepared by a novel method in which hydrolysis and condensation of titanium tetraisopropoxide (TTIP) and tetraethoxysilane (TEOS) were controlled by the pH change of acidic solution. The Pt-modified TiO2–SiO2 catalysts were synthesized by the photo-reduction method. The resulting materials showed a high photocatalytic activity for the photodegradation of methyl orange in the visible-light range. A reaction mechanism was proposed and discussed.

Ordered amino-functionalized mesoporous organic–inorganic hybrid silica thin films were prepared by evaporation induced self-assembly in acidic conditions. DNA molecules were covalently bound to these mesoporous substrates and characterized by transmission electron microscopy, atomic force microscopy and laser scanning confocal fluorescence microscopy.

Titanium dioxide thin films supported on glass containing 0.1, 0.5 and 0.8 at% of platinum-dopant were prepared by the microemulsion templating. The resulting films had an average size of TiO2 nanoparticles of 15–20 nm with a narrow size distribution and a mesoporous film structure. The thin films prepared showed a TiO2 anatase structure and shifted the UV–vis absorption to visible light region. The Pt-modified TiO2 thin films possessed the higher photocatalytic activity than that of TiO2 thin films alone for the photodegradation of the methyl orange dye in the visible light range. The mechanism of photocatalytic activity enhancement of the Pt-modified TiO2 thin films was discussed.

Amino-functionalized mesostructured cellular foams (AF-MCFs) with large mesopores have been prepared by co-condensation of tetraethoxysilane (TEOS) and 3-aminopropyl-triethoxysilane (ATES) using oil-in-water microemulsion template. These resulting materials had disordered mesopores with well-defined large mesopore frameworks and amino functional groups adding to their interior surfaces.

Large mesoporous aluminas have been prepared by the hydrolysis of aluminum tri-sec-butoxide in the presence of cetyltrimethylammonium bromide (CTAB) using oil-in-water microemulsion template. These resulting materials showed a disordered mesostructure with large mesopore frameworks. It is found to convert the intermediate phase (hydrated pseudoboehmite) into γ-Al2O3 at 268.7 °C. The large mesoporous alumina materials possess relative narrow mesoporous size distribution, high surface area (407.2 m2/g) and pore volumes (0.877 cm3/g). The prepared materials exhibited higher performance as catalyst support than that of the similar commercial γ-Al2O3 granules.

The mass production of graphene and nitrogen-doped (N-doped) graphene constitutes one of the main obstacles for the application of these materials. We demonstrate a novel resin-based methodology for large-scale self-assembly of the N-doped graphene. The N-doped graphene is readily obtained by using a precursor containing nitrogen and metal ions. The N-doped graphene is characterized by Raman, AFM, TEM, SEM, synchronic radiation and XPS measurements. The electrochemical performance of the catalyst made with such materials is investigated by a rotating ring-disk electrode (RRDE) system. The results reveal that the N-doped graphene is a selective catalyst and possesses an outstanding electrocatalytic activity, long-term stability, and good methanol and CO tolerance for oxygen reduction reaction (ORR).