C O M M U N I C A T I O N S
Table 1. Physical and Structural Properties of Selected Mesoporous and Macroporous-Mesoporous Samples
a
)
c
)
f
sample
SBET (m2 g-1
Dmesopore (nm)b
Vmesopore (cm3 g-1
Dmacropore (nm)d
d100 (nm)e
wall thickness (nm)
crystal phase
Al-M
Al-M300-M
Al-M400-M
259
249
207
5.8
5.1
4.0
0.54
0.49
0.40
-
212
320
9.5
9.7
9.9
5.2
6.1
7.5
none
none
none
a Specific surface area obtained from adsorption data in the range 0.07 < P/P0 < 0.30. b Mesopore diameter taken at the middle of the segment
defined by the peak width at half height (BJH pore size distribution). c Mesopore volume evaluated for P/P0 > 0.980. d Average macropore diameter
obtained using TEM. e Interplanar spacing determined from Bragg’s law. f Wall thickness calculated for a hexagonal system ) (2d100/ꢀ3) - Dmesopore
.
mesoporous alumina (Table 1). The incorporation of macropores
only slightly perturbs the isotherm shown in Figure S6A, which
remains of type IV (characteristic of a mesoporous solid), albeit
with reduced mesopore volume. The corresponding pore size
distributions shown in Figure S6B are also narrow, consistent with
the regular pores seen by TEM, while the surface areas are higher
than for either commercial γ-alumina or macroporous Al2O3 from
previous syntheses.21,22 Our materials are robust and thermally
stable up to 800 °C (Figure S7) and amenable to simple multigram
production.
The combination of high surface area, thick-walled ordered
mesopores, and very uniform macropores paves the way to new
alumina supports that have predictable diffusion characteristics and
are ideal for functionalization by metal nanoparticles and application
in liquid/gas-phase catalysis.
Acknowledgment. We thank the Engineering and Physical
Sciences Research Council for financial support (EP/F063423/1;
EP/G007594/1) and the award of a Leadership Fellowship (A.F.L.).
We thank Serge Kaliaguine and Se´bastien Vaudreuil (Laval
University) for advice on latex bead synthesis.
Figure 2. Low-angle XRD patterns obtained for the mesostructured alumina
Al-M (a) and the two macro-mesostructured solids Al-M300-M (b) and
Al-M400-M (c).
work clearly comprises well-defined channels arising from ordered,
hexagonally packed mesopores (Figure 1C and Figure S4b,c). As
discussed in the literature,19 the mesopore network may be perturbed
by the interpenetrating spherical macropores, which inevitably place
geometric constraints on hexagonal cells within the mesopore
network in macroporous-mesoporous solids. Notably, the macro-
structure cell contraction seen during calcination does not influence
the associated macropore periodicity.
Supporting Information Available: Detailed materials synthesis
and characterization. This material is available free of charge via the
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