Nanocasting synthesis of BiFeO₃ nanoparticles with enhanced visible-light photocatalytic activity

• Thomas Cadenbach,
• Maria J. Benitez,
• A. Lucia Morales,
• Cesar Costa Vera,
• Luis Lascano,
• Francisco Quiroz,
• Alexis Debut and
• Karla Vizuete

Beilstein J. Nanotechnol. 2020, 11, 1822–1833, doi:10.3762/bjnano.11.164

• Fuerzas Armadas ESPE, Av. Gral. Rumiñahui s/n, Sangolquí, PO Box 171-5-231B, Ecuador 10.3762/bjnano.11.164 Abstract In this work, monodisperse BiFeO3 nanoparticles with a particle diameter of 5.5 nm were synthesized by a nanocasting technique using mesoporous silica SBA-15 as a hard template and pre

• radical trapping experiments. Keywords: bismuth ferrite (BiFeO3); dye; nanocasting; nanoparticles; photocatalysis; rhodamine B; SBA-15; Introduction In the face of a continuously growing demand, the production of safe and readily available water is one of the biggest challenges humanity is facing

• diameter corresponding to the pore size of the porous matrix and, consequently, by a high specific surface area. Silica matrices, such as Santa Barbara Amorphous silica (SBA-15) or Korean Advanced Institute of Science and Technology silica (KIT-6), have been used successfully as hard templates to

Photoactive nanoarchitectures based on clays incorporating TiO₂ and ZnO nanoparticles

• Eduardo Ruiz-Hitzky,
• Pilar Aranda,
• Marwa Akkari,
• Nithima Khaorapapong and
• Makoto Ogawa

Beilstein J. Nanotechnol. 2019, 10, 1140–1156, doi:10.3762/bjnano.10.114

• to the NPs confined in the nanopores, is still an important challenge. Recently, the size-controlled synthesis of TiO2 NPs within mesoporous silica (SBA-15) has been reported, where, according to Vibulyaseak and co-workers [70], the NPs formation occurred exclusively in the mesopores. The aim of this

Thermal control of the defunctionalization of supported Au₂₅(glutathione)₁₈ catalysts for benzyl alcohol oxidation

• Zahraa Shahin,
• Hyewon Ji,
• Rodica Chiriac,
• Nadine Essayem,
• Franck Rataboul and
• Aude Demessence

Beilstein J. Nanotechnol. 2019, 10, 228–237, doi:10.3762/bjnano.10.21

• has been shown that the presence or absence of the thiolate ligand affects the catalytic activity and selectivity of gold thiolate clusters [17][18]. For example, high activity in the aerobic epoxidation of trans-stilbene was observed using non-calcined Au25(SPhNH2)17@SBA-15, whereas upon calcination

• 4 h and showed full conversion of benzyl alcohol into mostly benzoic acid, under 1 atm of O2 at 30 °C using a base [17]. In a previous study by our group, Au25(SPhNH2)17@SBA-15, calcined at 400 °C to fully remove the ligands, induced the full conversion of benzyl alcohol after a couple of hours in

• general, supported gold thiolate clusters are known to grow when calcined at high temperature [24], except when they are inserted in a porous material, such as SBA-15 [21], or loaded with a very small quantity of clusters [22]. Here we note that the gold clusters maintain a diameter of around 2 nm or

pH-mediated control over the mesostructure of ordered mesoporous materials templated by polyion complex micelles

• Emilie Molina,
• Mélody Mathonnat,
• Jason Richard,
• Patrick Lacroix-Desmazes,
• Martin In,
• Philippe Dieudonné,
• Thomas Cacciaguerra,
• Corine Gérardin and
• Nathalie Marcotte

Beilstein J. Nanotechnol. 2019, 10, 144–156, doi:10.3762/bjnano.10.14

• condensation step is triggered with the aid of sodium fluoride and/or pH adjustment [19]. Separating the hydrolysis of TEOS from the condensation step enabled highly ordered 2D hexagonal SBA-15-type [20] and cubic [21][22] SBA-16-type materials to be obtained up to pH 5 and pH 4–4.5, respectively. Since 2008

• was not trapped into silica walls of the materials but rather acted as a porogen agent contributing to the mesopore volume once the materials were calcined. Such an occurrence is reminiscent of the size increase of the structural mesopores of SBA-15 materials observed at temperature of synthesis

Cr(VI) remediation from aqueous environment through modified-TiO₂-mediated photocatalytic reduction

• Rashmi Acharya,
• Brundabana Naik and
• Kulamani Parida

Beilstein J. Nanotechnol. 2018, 9, 1448–1470, doi:10.3762/bjnano.9.137

• support. The photogenerated electrons are transported from the Mn-doped TiO2 through RGO and were found to reduce the adsorbed Cr(VI) [137]. A Ti–SBA-15–g-C3N4 material was also shown to exhibit higher Cr(VI) photoreduction under visible light illumination. The Ti moiety in Ti–SBA-15 can extract the

Understanding the performance and mechanism of Mg-containing oxides as support catalysts in the thermal dry reforming of methane

• Nor Fazila Khairudin,
• Mohd Farid Fahmi Sukri,
• Mehrnoush Khavarian and
• Abdul Rahman Mohamed

Beilstein J. Nanotechnol. 2018, 9, 1162–1183, doi:10.3762/bjnano.9.108

• unstable when the catalyst was exposed to an excessively long treatment time. Wang et al. [119] prepared and analyzed a MgO-SBA-15 catalyst via two different methods, which are the one-pot synthesis method and impregnation method as shown in Figure 9a. As a result, the catalyst prepared using the one-pot

• synthesis showed a better order of MgO-coated sample in the mesostructure of SBA-15, a larger BET surface area, and formed more basic sites compared to the conventional impregnation method. The authors further impregnated the basic sites with nickel metal and tested it in DRM. The MgO-coated Ni/SBA-15

• catalysts showed greater catalyst performance and stability compared to the Ni/SBA-15 sample. Figure 9b depicts the total petroleum hydrocarbons (TPH) profiles of spent catalyst after 40 h of stability. It is interesting to note that 8 wt % of MgO loading exhibited excellent catalytic activity. The SBA-15

Review on optofluidic microreactors for artificial photosynthesis

• Xiaowen Huang,
• Jianchun Wang,
• Tenghao Li,
• Jianmei Wang,
• Min Xu,
• Weixing Yu,
• Abdel El Abed and
• Xuming Zhang

Beilstein J. Nanotechnol. 2018, 9, 30–41, doi:10.3762/bjnano.9.5

• membrane-based reactors were reported as well, for instance, mesoporous CdS/TiO2/SBA-15@carbon paper composite membranes [77] and copper-decorated TiO2 nanorod thin films [78]. In addition to the PDMS/PMMA-based microchannel reactors, bacterium has been shown to be a good microreactor as well. Yang et al

One-step chemical vapor deposition synthesis and supercapacitor performance of nitrogen-doped porous carbon–carbon nanotube hybrids

• Egor V. Lobiak,
• Lyubov G. Bulusheva,
• Ekaterina O. Fedorovskaya,
• Yury V. Shubin,
• Pavel E. Plyusnin,
• Pierre Lonchambon,
• Boris V. Senkovskiy,
• Zinfer R. Ismagilov,
• Emmanuel Flahaut and
• Alexander V. Okotrub

Beilstein J. Nanotechnol. 2017, 8, 2669–2679, doi:10.3762/bjnano.8.267

• works devoted to one-step formation of porous carbon–CNT hybrids for energy storage applications. Lei et al. have reported the CCVD synthesis of nitrogen-doped ordered mesoporous carbon and multiwalled CNTs (MWCNTs) with the use of a silica SBA-15 template impregnated by iron nitrate [14

Cantilever bending based on humidity-actuated mesoporous silica/silicon bilayers

• Christian Ganser,
• Gerhard Fritz-Popovski,
• Roland Morak,
• Parvin Sharifi,
• Benedetta Marmiroli,
• Barbara Sartori,
• Heinz Amenitsch,
• Thomas Griesser,
• Christian Teichert and
• Oskar Paris

Beilstein J. Nanotechnol. 2016, 7, 637–644, doi:10.3762/bjnano.7.56

• the plane of the film is random. From the positions of the diffraction peaks, the lattice symmetry can easily be deduced. As reported already in earlier work [24], this symmetry deviates considerably from the 2D hexagonal lattice found for powder SBA-15 materials [25]. This is understood by the fact

• [35][36]. The value of EF ≈ 5.0 GPa obtained from Equation 2 agrees indeed fairly well with the one found in SBA-15 (EF ≈ 6 GPa) with a similar volume fraction of mesopores [27]. Now we try to estimate the maximum sorption-induced deformation ε and thus, the cantilever deflection, on a more

• SBA-15 [40] show that this drop may be rather small for the adsorption branch. There should be, however, a clear increase in slope above capillary condensation, which is seen in both, the strain isotherm (Figure 4) and the cantilever deflection (Figure 2) at RH ≈ 70–80%. To come to an estimate for the

Nanoporous composites prepared by a combination of SBA-15 with Mg–Al mixed oxides. Water vapor sorption properties

• Amaury Pérez-Verdejo,
• Alvaro Sampieri,
• Heriberto Pfeiffer,
• Mayra Ruiz-Reyes,
• Juana-Deisy Santamaría and
• Geolar Fetter

Beilstein J. Nanotechnol. 2014, 5, 1226–1234, doi:10.3762/bjnano.5.136

• nanostructured mesoporous composites by interconnecting and combining SBA-15 with mixed oxides derived from a calcined Mg–Al hydrotalcite. Two different Mg–Al hydrotalcite addition procedures were implemented, either after or during the SBA-15 synthesis (in situ method). The first procedure, i.e., the post

• -synthesis method, produces a composite material with Mg–Al mixed oxides homogeneously dispersed on the SBA-15 nanoporous surface. The resulting composites present textural properties similar to the SBA-15. On the other hand, with the second procedure (in situ method), Mg and Al mixed oxides occur on the

• might be utilized as as acid-base catalysts, adsorbents, sensors or storage nanomaterials. Keywords: calcined Mg–Al hydrotalcite; nanoporous composites; SBA-15; vapor sorption; Introduction Multifunctional nanomaterials are designed to satisfy specific ranged sets of performance requirements. The

Thermal stability and reduction of iron oxide nanowires at moderate temperatures

• Annalisa Paolone,
• Marco Angelucci,
• Stefania Panero,
• Maria Grazia Betti and
• Carlo Mariani

Beilstein J. Nanotechnol. 2014, 5, 323–328, doi:10.3762/bjnano.5.36

• mesoporous silica (SBA-15) synthesized through the sol–gel method. In order to embed the iron oxide nanowires, 0.01 M Fe(NO3)3·9H2O was dissolved in 50 mL of ethanol and added to 1 g of SBA-15. This solution was mixed at room temperature, dried at 310 K for 1 week, and the resulting powder was sintered at

Synthesis and catalytic applications of combined zeolitic/mesoporous materials

• Jarian Vernimmen,
• Vera Meynen and
• Pegie Cool

Beilstein J. Nanotechnol. 2011, 2, 785–801, doi:10.3762/bjnano.2.87

• counterparts, such as a diminished crystallinity, resulting in a loss of catalytic activity and lower stability [20][21]. The second option is the creation of nanoporous materials with larger pores, namely mesoporous materials, such as SBA-15 [22][23], SBA-16 [23], M41S [24][25][26], MSU [27][28][29][30][31

• , due to the harsh acidic medium that is required for the synthesis of SBA-15, leaching of heteroelements such as Ti is unavoidable during in situ syntheses, limiting their catalytic activity [39][40][41][42]. Moreover, in some occasions the amorphous siliceous framework hampers the solid incorporation

• SBA-15) or to fill the mesopores with a support material (such as the mesotemplate [77]) in order to prevent a collapse of the mesopores during zeolitization. An example of a combined zeolitic/mesoporous material synthesized by the recrystallization route is UL-TS-1, which is formed by heating TPAOH

Inorganic–organic hybrid materials through post-synthesis modification: Impact of the treatment with azides on the mesopore structure

• Miriam Keppeler,
• Jürgen Holzbock,
• Johanna Akbarzadeh,
• Herwig Peterlik and
• Nicola Hüsing

Beilstein J. Nanotechnol. 2011, 2, 486–498, doi:10.3762/bjnano.2.52

• [38][39]. This has been experimentally and theoretically used to model the electron density across the pore for modified and unmodified MCM-41 and SBA-15 materials [11][40] (for detailed information on SAXS data evaluation, see Supporting Information File 1). The best solution for the three observed

• reflections in our case was −+−, which differs to the phase shift from −−++ for the first four coefficients for the SBA 15 material observed by Flodström et al. or −++− for the MCM 41 material [11][40]. This could be due to the variations in the synthesis conditions of the different materials. As an example

Pore structure and surface area of silica SBA-15: influence of washing and scale-up

• Jörg P. Thielemann,
• Frank Girgsdies,
• Robert Schlögl and
• Christian Hess

Beilstein J. Nanotechnol. 2011, 2, 110–118, doi:10.3762/bjnano.2.13

• , 64287 Darmstadt, Germany 10.3762/bjnano.2.13 Abstract The removal of the surfactant (EO20PO70EO20) by washing before final calcination is a critical step in the synthesis of silica SBA-15. In contrast to washing with pure water or ethanol, washing with water and ethanol may, depending on the quantity

• of solvent used, alter the homogeneity and order of the pores, but also lead to an increase of the surface area of SBA-15. A reduction of solvent volume and a controlled washing protocol allow the synthesis of high surface area SBA-15 materials with a narrow monomodal pore size distribution. For

• larger batch sizes the influence of the quantity of solvent on the quality of the SBA-15 is reduced. Keywords: SBA-15; scale-up; silica mesoporous material; tensile strength effect; washing; Introduction SBA-15 is a mesoporous silica sieve based on uniform hexagonal pores with a narrow pore size

Synthesis of LiNbO₃ nanoparticles in a mesoporous matrix

• Anett Grigas and
• Stefan Kaskel

Beilstein J. Nanotechnol. 2011, 2, 28–33, doi:10.3762/bjnano.2.3

• Anett Grigas Stefan Kaskel Department of Inorganic Chemistry, Dresden University of Technology, Mommsenstraße 6, D-01062 Dresden, Germany 10.3762/bjnano.2.3 Abstract The synthesis of LiNbO3 nanoparticles in SBA-15 is reported for the first time. The preparation of nanoparticles was carried out by

• impregnation from the metal precursor and mesoporous silica SBA-15 as the template. A rapid one-step treatment in an IR furnace reduces the preparation time to only 10 min. In comparison, a conventional furnace requires 5 h reaction time to produce nanoparticles with similar textural properties. Another

• ). The obtained nanoparticles are spherical with a diameter of approximately 10 nm. Keywords: LiNbO3; ordered mesoporous material; SBA-15; template synthesis; Introduction Lithium niobate is one of the most important ferroelectric materials. At room temperature it has a rhombohedral symmetry and space