0000000000000253
AUTHOR
Mónica Pérez-cabero
Hierarchical porous carbon with designed pore architecture and study of its adsorptive properties
Abstract Ordered mesoporous carbon nanoparticles have been synthesized by a nanocasting procedure from furfuryl alcohol impregnation into alumino–silica UVM-7 material. By a proper adjustment of the synthesis parameters, furfuryl alcohol volume vs . template pore volume, it was possible to obtain a carbonaceous templated material which keeps the hierarchical bimodal porosity of the silica together with its high surface area (>1000 m 2 /g), as it was confirmed by means of electron transmission microscopy and N 2 adsorption isotherms. This carbon material was evaluated by testing it as a sorbent for several pesticides in aqueous solutions. Its absorption efficiency was compared with typical c…
Mesoporous aluminum phosphite
Abstract High surface area pure mesoporous aluminum-phosphorus oxide-based derivatives have been synthesized through an S+I− surfactant-assisted cooperative mechanism by means of a one-pot preparative procedure from aqueous solution and starting from aluminum atrane complexes and phosphoric and/or phosphorous acids. A soft chemical extraction procedure allows opening the pore system of the parent as-prepared materials by exchanging the surfactant without mesostructure collapse. The nature of the pore wall can be modulated from mesoporous aluminum phosphate (ALPO) up to total incorporation of phosphite entities (mesoporous aluminum phosphite), which results in a gradual evolution of the acid…
Stable anchoring of dispersed gold nanoparticles on hierarchic porous silica-based materials
The nanometric organization of MOx (M = Co, Zn, Ni) domains partially embedded inside the mesoporous silica walls but accessible to the pore voids, which is achieved through a simple one-pot surfactant-assisted procedure, define optimal anchors for the nucleation and growth of gold nanoparticles, which in turn favours an exceptional thermal stability for the final Au-supported materials. As silica support we have selected a UVM-7 silica having a highly accessible architecture defined by two hierarchic pore systems. The combination of nanometric pore length, tortuous mesopores and MOx inorganic anchors favours the stability of the final Au/CoOx-UVM-7 nanocomposites.
Nano-sized mesoporous carbon particles with bimodal pore system and semi-crystalline porous walls
Acetylene CVD carbon replication of a hierarchical pore silica-based material, Fe-UVM-7, is reported. The original template organization, which is based on the aggregation of mesoporous nanoparticles, is accurately replicated in the final carbon material: a bimodal porous carbon combining mesoporous nanoparticles and inter-particle textural-like pores which provide high surface area, a highly accessible pore system and semi-crystalline pore walls in the form of graphitic-like nanodomains is presented.
Effects of functionalized carbon nanotubes in peroxide crosslinking of diene elastomers
Abstract The crosslinking reaction of ethylene–propylene–diene terpolymer (EPDM) peroxide vulcanization filled with pristine and functionalized carbon nanotubes (CNTs and S/CNTs) was evaluated by rheometric tests. The functionalization of CNTs was carried out by diazonium salt methodology in acid medium. S/CNTs were characterised by means of TGA, EDX, Raman and elemental analysis. Pristine CNTs were found to gradually increase the delta torque as a function of loading fraction. Nevertheless, the vulcanization time, scorch and optimum cure time hardly varied on addition of CNTs. However, S/CNTs noticeably affected the cure process, reducing the vulcanization time and delta torque. This effec…
Polyfurfuryl alcohol composite as adsorbent of polychlorinated biphenyls and pyrethroid insecticides
Abstract Composites from furfuryl alcohol and silica gel were prepared in dichloromethane using trifluoroacetic acid as catalyst and characterized by means of thermogravimetric analysis, transmission electron microscopy and nitrogen adsorption–desorption isotherms. The polymer content in the composites ranged between 19.5% and 32.9%. The capability to adsorb polychlorinated biphenyls and pyrethroid insecticides was tested for composite samples containing different percentages of polymer. Pyrethroids are retained almost totally by composites containing around 24–33% of polymer, while recovery of PCBs close to 80% is obtained with all the composites. No selectivity between compounds of the sa…
Thalassiosira pseudonana diatom as biotemplate to produce a macroporous ordered carbon-rich material
Abstract Ordered macroporous–mesoporous carbonaceous materials were produced as a direct replica of the Thalassiosira pseudonana diatom by infiltration of the skeleton with furfuryl alcohol. The final carbon-rich material preserves the macropores of the diatom acting as bio-template and new hierarchical macro–mesopores appears as the silica is eliminated through chemical etching. The final solid can be described as an organized array of carbon macrotubes. In order to understand the progressive silica etching and the subsequent effect on the final carbon material, different etching reagents have been used. Moreover, the similar pore topology of T. pseudonana and the well known MCM-41 mesopor…
Total oxidation of VOCs on Au nanoparticles anchored on Co doped mesoporous UVM-7 silica
Abstract Gold deposited on a cobalt containing siliceous mesoporous structure, UVM-7, presents a good catalytic performance in the total oxidation of propane and toluene. The presence of both gold and cobalt is necessary as bimetallic Au/Co-UVM-7 catalysts are remarkably more active than monometallic Au/UVM-7 or Co-UVM-7 catalysts. The improved activity of the bimetallic AuCo-samples if compared to gold free cobalt catalysts can be explained on the basis of the enhanced reducibility of some cobalt species in the presence of gold, which facilitates the redox cycle. This high reducibility of cobalt species in the bimetallic samples is probably due to the formation of Co 3 O 4 domains at the g…
Mesosynthesis of ZnO-SiO(2) porous nanocomposites with low-defect ZnO nanometric domains.
Silica-based ZnO-MCM-41 mesoporous nanocomposites with high Zn content (5≤Si/Zn≤50) have been synthesized by a one-pot surfactant-assisted procedure from aqueous solution using a cationic surfactant (CTMABr = cetyltrimethylammonium bromide) as structure-directing agent, and starting from molecular atrane complexes as inorganic hydrolytic precursors. This preparative technique allows optimization of the dispersion of the ZnO nanodomains in the silica walls. The mesoporous nature of the final materials is confirmed by x-ray diffraction (XRD), transmission electron microscopy (TEM) and N(2) adsorption-desorption isotherms. The ZnO-MCM-41 materials show unimodal pore size distributions without …