From the Special Topic of
According to our recent Special Topic on mesoporous
materials over the past decade, the scientist ranking at #2
by total number of papers and #12 by total citations is
Professor Mietek Jaroniec, with 80 papers cited a total of
Science IndicatorsSM from
Reuters, Prof. Jaroniec's record includes 198 papers,
mostly classified in the fields of Chemistry and Materials
Science, cited a total of 5,861 times between January 1,
1998 and April 30, 2008. Prof. Jaroniec hails from Kent
State University in Kent, Ohio, where he is a Professor in
the Department of Chemistry.
In the interview below,
he talks with ScienceWatch.com about his
frequently cited work.
Please tell us a little about your
educational and research background.
I was born in Poland and underwent higher education in chemistry at the
Marie Curie-Sklodowska University in Lublin, Poland, where I received an
equivalent degree of M. Sc. in 1972, a Ph.D. in 1976, and a Doctor of
Science degree in 1979. In 1985 I received a title of Professor and was a
faculty member in the Department of Chemistry at the M. Curie-Sklodowska
University until 1991.
In the meantime, I had a few visiting appointments, including Georgetown
University (1984-85), McMaster University (1985-86) and Kent State
University (1987, 1988-89). In 1991, I moved to Kent State University and
have been a chemistry professor there since. In 2005 I received an Honorary
Professor title from my alma mater.
What first interested you in mesoporous
The term "mesoporous materials" refers to solids with broad or narrow
distribution of pores in the range between 2 and 50 nm, which form a
disordered or ordered network. In my studies at M. Curie-Sklodowska
University, I was primarily interested in interfacial chemistry, especially
in physical adsorption from the gas and liquid phases on microporous (pore
widths below 2 nm) and mesoporous solids. The solids studied, including
carbons, silica gels, and other inorganic materials, featured broad pore
size distributions and disordered porosity.
"The past fifteen years of remarkable
progress in the synthesis of OMM have been
accompanied by the development of a wide variety
of potential applications of these
One of the intriguing questions, which initially attracted my attention,
was the effect of pore size distribution (structural heterogeneity) on
physical adsorption and related phenomena. It soon became evident that the
computer simulations and experimental studies of adsorption in uniform
mesopores are essential for modeling physical adsorption in heterogeneous
mesoporous solids. Therefore, two pioneering papers from Mobil Co. (Kresge
CT, et al., "Ordered mesoporous molecular sieves synthesized by a
liquid crystal template mechanism," Nature 359: 710-2, 22
October 1992; Beck JS, et al., "A new family of mesoporous
molecular sieves prepared with liquid crystal templates," JACS
114: 10834-43, 30 December 1992), reporting the self-assembly synthesis
of ordered mesoporous silicas of hexagonal and cubic symmetry, immediately
attracted my attention. These two papers initiated a separate research
field spawning about ten thousand publications; because of this, the term
"mesoporous materials" is often identified with "ordered mesoporous
My adsorption experience primarily directed me towards usage of these
well-defined mesostructures as model adsorbents for the refinement of the
existing methods and the development of new ones for characterization of
mesoporous materials. My prior experience in the organosilane modification
of silica particles for chromatographic separations inspired me to study
ordered mesoporous organosilicas. In the first case I was fortunate to
collaborate with a highly motivated and talented graduate student and
postdoctoral fellow, Michal Kruk (currently assistant professor at CUNY,
Staten Island), and Professor Abdel Sayari (currently at Ottawa
University). This collaboration led to the development of a simple and
accurate method of pore size analysis of channel-like mesoporous materials
("Application of large-pore MCM-41 molecular sieves to improve pore size
analysis using nitrogen adsorption measurements," Langmuir 13:
6267-73, 12 November 1997), which is known as the KJS method.
The development of ordered mesoporous organosilicas has been an equally
exciting topic because the self-assembly of appropriate organosilanes and
surfactants or block copolymers creates almost unlimited possibilities in
the synthesis of novel organosilica mesostructures of tailored porosity,
surface and framework properties, and morphology.
Your most-cited paper in our Special Topics
analysis is the 2001 Advanced Materials paper, "Ordered
mesoporous carbons." Would you talk a little bit about this
paper—its findings and the significance for the field?
The popularity of this paper illustrates the importance of timely and
concise review articles in rapidly growing areas of research. At the end of
1999 Professor Ryong Ryoo and co-workers from the Korean Advanced Institute
of Science and Technology (KAIST) reported in J. Phys. Chem. B the
synthesis of ordered mesoporous carbon (OMC) by using a cubic OMS, MCM-48,
as a hard template. The hard-templating synthesis (nanocasting) involves
the filling of pores of the template with carbon precursor, carbonization
of the latter, and the dissolution of the siliceous template.
The 2001 Advanced Materials paper was the first review article
devoted to the OMC materials; it was published just two years after
discovery of OMC. Since the hard-templating synthesis of OMCs was one of
the major advancements in the area of ordered mesoporous materials, this
concise review attracted the attention of many scientists and stimulated
the further development of OMCs.
Your most-cited paper overall in Essential
Science Indicators is the 2000 Journal of the American
Chemical Society paper, "Synthesis of a new, nanoporous carbon
with hexagonally ordered mesostructures." Why do you think this paper
has garnered so much attention?
Porous carbons, especially active carbons, have been known for thousands of
years because of their common usage in purification, pre-concentration, and
separation processes. From a physicochemical viewpoint, active carbons are
structurally heterogeneous due to the presence of fine pores (mainly
micropores) of different sizes, shapes, and connectivity, which limit their
accessibility to small molecules and hinder molecular transport through the
pore network. Therefore, there was a great interest in the development of
mesoporous carbons in order to extend their applicability for adsorption of
larger molecules and to improve the kinetics of the aforementioned
processes. Several recipes, which have been proposed for the development of
mesoporous carbons, afforded materials with broad distribution of pores and
Two landmark papers published in 1998 and 1999 showed a new way for the
synthesis of carbons with ordered pores; the first one (Zakhidov AA, et
al., "Carbon structures with three-dimensional periodicity at optical
wavelengths," Science 282: 897-901, 30 October 1998) is
devoted to the fabrication of ordered macroporous (pore widths above 50 nm)
carbons by using siliceous colloidal crystals as hard templates, whereas
the second one (Ryoo R, Joo SH, Jun S, "Synthesis of highly ordered carbon
molecular sieves via template-mediated structural transformation," J.
Phys. Chem. B 103: 7743-6, 16 September 1999) reports the
synthesis of ordered mesoporous carbons using the MCM-48 templates. Since
the MCM-48 cubic structure consists of two interwoven three-dimensional
pore systems, the resulting carbon is not a true inverse replica of the
template because of a structural change during templating synthesis.
"The popularity of this paper
illustrates the importance of timely and concise
review articles in rapidly growing areas of
In contrast, the JACS paper (a collaborative effort of Professors
Ryoo, Terasaki, myself, and our co-workers) reports the first synthesis of
OMC, which is a true inverse replica of SBA-15 (hexagonally ordered
mesoporous silica, OMS). This work shows the possibility of tailoring the
OMC structure by selection of appropriate siliceous hard templates. Also,
it provides additional evidence on the presence of interconnecting fine
pores in SBA-15 (see response to the next question).
The SBA-15 template (which consists of hexagonally ordered cylindrical
mesopores interconnected by irregular micropores), after filling its pores
completely with carbon precursor followed by carbonization and silica
dissolution, gives the inverse carbon replica, which is a collection of
hexagonally ordered carbon rods interconnected by irregular carbon wires.
If pores of the SBA-15 template are not filled completely, the resulting
replica consists of hexagonally ordered interconnected carbon nanopipes.
This example shows the attractiveness of hard-templating synthesis for
fabrication of various carbon nanostructures. An additional advantage of
this synthesis is the preservation of template morphology when the
three-dimensional rigid OMSs are used as hard templates.
Another key paper is the 2000 Chemistry of
Materials paper, "Characterization of the porous structure of
SBA-15." Would you sum up this paper and its findings for our
SBA-15, one of the most-popular OMMs reported in 1998 in Science
(Zhao DY et al., "Triblock copolymer synthesis of mesoporous silica with
periodic 50 to 300 angstrom pores," 279: 548-52), is a hexagonally
ordered mesoporous silica obtained by using poly(ethylene
oxide)-poly(propylene oxide)-poly(ethylene oxide) block copolymers as soft
templates. Initially, it was suggested that SBA-15 is a large-pore
counterpart of MCM-41, which is a solely mesoporous material synthesized by
using cationic surfactants as soft template. According to this suggestion,
the only difference between SBA-15 and MCM-41 was the size of mesopores,
which in the former case were much larger. Thus, both MCM-41 and SBA-15
were supposed to be two-dimensional (2D) hexagonally ordered mesoporous
The 2000 Chemistry of Materials paper and subsequent one (J.
Phys. Chem. B) shows that this is not true for the SBA-15 samples
reported so far. In fact, SBA-15 exhibits a 3D microporous-mesoporous
network, which consists of 2D hexagonally ordered cylindrical mesopores
interconnected by irregular complementary pores such as micropores and fine
mesopores. An accurate analysis of adsorption data, post-synthesis
modification, and inverse replication studies proved the presence of
complementary fine pores in the mesopore walls of SBA-15. Solid evidence
has been provided by the above JACS paper, which reports a
successful synthesis of a true inverse carbon replica of SBA-15; this would
be impossible if SBA-15 had no interconnecting microporosity.
What are the practical applications (or potential
applications) of these materials?
In the preface of a recent special issue "Templated materials" of
Chemistry of Materials (20: 599-600, 12 February 2008) edited
by Professor Ferdi Schüth and myself, we wrote:
"The past fifteen years of remarkable progress
in the synthesis of OMM have been accompanied by the development of a wide
variety of potential applications of these materials,
ranging from adsorption, catalysis, separations, gas storage and
environmental cleanup to drug delivery, sensing devices, optoelectronics,
nanotechnology, energy storage and conversion." This special issue contains
many invited reviews and original papers, which report on the potential
applications of OMMs.
What should the "take-away lesson" be about your
Soft-templating and hard-templating strategies provide tremendous
possibilities for the synthesis of novel ordered mesostructures of tailored
porosity, surface and framework properties, and morphology. Examples of the
aforementioned OMMs as well as extensively studied metal-organic frameworks
(MOFs) show that we are still in the beginning of an exciting journey and a
lot will be done in the development of novel ordered nanostructures and
especially in the area of their applications.
The three papers presented in this interview were performed in
collaboration with Professor Ryoo’s group (KAIST), which is one of
the most active and productive groups in the area of OMMs. The
aforementioned papers show how much can be done through international
collaboration. Therefore, I would like to thank Prof. Ryoo and his group as
well as other past and current graduate students and collaborators for
their fruitful interactions.
Mietek Jaroniec, Ph.D.
Department of Chemistry
Kent State University
Kent, OH, USA
Jaroniec's most-cited paper with
473 cites to date:
Jun S, et al., "Synthesis of new, nanoporous
carbon with hexagonally ordered mesostructure," J. Am.
Chem. Soc. 122(43): 10712-3, 1 November 2000. Source:
Essential Science Indicators from
View a Fast Moving Front comment by
Mietek Jaroniec from 2004.
Keywords: mesoporous materials, interfacial chemistry, pore
size distribution, structural heterogeneity, physical adsorption,
mesoporous organosilicas, ordered mesoporous carbons, SBA-15, soft
templating, hard templating, ordered nanostructures.