Facile fabrication of hierarchically porous carbonaceous monoliths with ordered mesostructure via an organic organic self-assembly

Abstract

A simple strategy for the synthesis of macro-mesoporous carbonaceous monolith materials has been demonstrated through an organic organic self-assembly at the interface of an organic scaffold such as polyurethane (PU) foam. Hierarchically porous carbonaceous monoliths with cubic (Im m) or hexagonal (p6mm) mesostructure were prepared through evaporation induced self-assembly of the mesostructure on the three-dimensional (3-D) interconnecting struts of the PU foam scaffold. The preparation was carried out by using phenol/formaldehyde resol as a carbon precursor, triblock copolymer F127 as a template for the mesostructure and PU foam as a sacrificial monolithic scaffold. Their hierarchical pore system was macroscopically fabricated with cable-like mesostructured carbonaceous struts. The carbonaceous monoliths exhibit macropores of diameter 100 450 μm, adjustable uniform mesopores (3.8 7.5 nm), high surface areas (200 870 m 2 /g), and large pore volumes (0.17 0.58) cm 3 /g. Compared with the corresponding evaporation induced self-assembly (EISA) process on a planar substrate, this facile process is a time-saving, labor-saving, space-saving, and highly effi cient pathway for mass production of ordered mesoporous materials.

Monolithic porous carbon materials prepared from polyurethane foam templates

“…In fact, at higher magnification (×5 k, not shown) no aggregates on the surface of the materials were noted, indicating that a homogeneous film of resol is formed in the surface of the foam and that this film is preserved after carbonization. These observations are in agreement with the literature [9]. At the highest magnification (Fig.…”

“…For mesoporous carbon powders obtained by the hard or the soft-templated methods, a large number of studies exist in the literature, including reviews considering their preparation methodologies and their characterization [1,[6][7][8]. On the other hand, for monolith mesoporous carbon prepared by soft-template methodologies, just a few studies exist in the literature [9]. In the present work we prepared mesoporous carbons using a non-ionic surfactant (Pluronic F127; Sigma, USA) in a matrix of open cell polyurethane foam, so that the final carbon material has the monolithic shape of the foam matrix, but also has hierarchical porosity, with macropores from the polyurethane foam, as well as inherent meso-and micro-pores.…”

Fe nanoclusters on the Ge(001) surface studied by scanning tunneling microscopy, density functional theory calculations and X-ray magnetic circular dichroism

“…1). It exhibits large terraces with the Ge dimers forming zig-zag rows oriented along the [1][2][3][4][5][6][7][8][9][10] direction, in agreement with previous studies [10,37] If the sample is left at room temperature under UHV conditions for more than one hour after Fe deposition, larger clusters are observed on the Ge(001) surface, similar to results obtained by Jordan et al [13]. Typical low temperature STM images of 0.2 ML of Fe on the Ge(001) surface are shown in Fig.…”

“…Annealing the Fe nanoclusters on the Ge(001) surface at 420 K for 30 minutes leads to the formation of nanorow structures (or linear nanocluster arrays) elongated along the [1][2][3][4][5][6][7][8][9][10] direction of the Ge dimer rows (Fig. 6a).…”

“…The self-assembly of atoms or molecules into ordered surface-supported nanostructures is one of the key topics in solid state physics and surface science [1][2][3][4][5][6][7][8][9]. One major reason for this attention is the prospect of controlling atomic scale structures on surfaces, which can lead to mass fabrication of usable systems and novel devices.…”