Atomic layer deposition-based tuning of the pore size in mesoporous thin films studied by in situ grazing incidence small angle x-ray scattering
Jolien Dendooven, Kilian Devloo-Casier, Matthias Ide, Kathryn Grandfield, Mert Kurttepeli, Karl F. Ludwig, Sara Bals, Pascal Van Der Voort, Christophe Detavernier
Atomic layer deposition (ALD) enables the conformal coating of porous materials, making the technique suitable for pore size tuning at the atomic level, e.g., for applications in catalysis, gas separation and sensing. It is, however, not straightforward to obtain information about the conformality of ALD coatings deposited in pores with diameters in the low mesoporous regime (< 10 nm). In this work, it is demonstrated that in situ synchrotron based grazing incidence small angle x-ray scattering (GISAXS) can provide valuable information on the change in density and internal surface area during ALD of TiO2 in a porous titania film with small mesopores (3-8 nm). The results are shown to be in good agreement with in situ x-ray fluorescence data representing the evolution of the amount of Ti atoms deposited in the porous film. Analysis of both data sets indicates that the minimum pore diameter that can be achieved by ALD is determined by the size of the Ti-precursor molecule.
The porous titanium nickelide is very popular in various industries due to unique combination of physical and mechanical properties such as shape memory effect, high corrosion resistance, and biocompatibility. The non-equilibrium molecular dynamics simulation was applied to study the influence of porosity degree on mechanical properties of porous amorphous titanium nickelide at uniaxial tension, uniaxial compression, and uniform shear. We have found that the porous amorphous alloy is characterized by a relatively large value of Young's modulus in comparison to its crystalline analogue. It has …
The structural and dynamical properties of water confined in nanoporous silica with a pore diameter of 2.7 nm were investigated by performing large-scale molecular dynamics simulations using the reactive force field. The radial distribution function and diffusion coefficient of water were calculated, and the values at the center of the pore agreed well with experimental values for real water. In addition, the pore was divided into thin coaxial layers, and the average number of hydrogen bonds, hydrogen bond lifetime, and hydrogen bond strength were calculated as a function of the radial distanc…
Mesoporous silica obtained with methyltriethoxysilane as co-precursor in alkaline medium
以正硅酸四乙酯（TEOS）和甲基三乙氧基硅烷（MTES）为原料，在乙醇和水的混合物中，以不同比例的二氧化硅前体，通过溶胶-凝胶法合成了介孔二氧化硅颗粒。在室温下以氨水为催化剂，十六烷基三甲基溴化铵（CTAB）为结构导向剂。氮吸附，X-射线衍射和小角中子散射给出了信息的MTES/TEOS摩尔比的函数的凝胶结构和孔形态的演变。热重和差热分析表明，随着MTES的加入，低分子量有机碎片的氧化放热峰向更高的温度移动。提出了一种室温下一锅法合成MCM-41型材料的方法，其中MTES浓度的变化允许改变疏水性，保持材料的特定性质，如有序的孔结构、大的比表面积和高孔隙率，使它们适合于在药物负载应用中选择性吸收客体物种。具体而言，所获得的材料具有圆柱形孔，比表面积高达1101 m2/g，总孔体积高达0.473 cm 3/g。所获得的介孔材料易于进一步官能化，以改善其在药物递送应用中对客体物种的选择性摄取。
We present a capacitance method to measure the adsorption of rod-like nematogens (4-cyano-4'-pentylbiphenyl, 5CB) from a binary liquid 5CB/methanol solution into a monolithic mesoporous silica membrane traversed by tubular pores with radii of 5.4 nm at room temperature. The resulting adsorption isotherm is reminiscent of classical type II isotherms of gas adsorption in mesoporous media. Its analysis by a model for adsorption from binary solutions, as inspired by the Brunauer-Emmett-Teller (BET) approach for gas adsorption on solid surfaces, indicates that the first adsorbed monolayer consists …
Formation and Thermodynamic Behavior of THF-Water Hydrates in Confined Mesoporous Media
Institute of Physics of Rennes, CNRS-University of Rennes 1（雷恩物理研究所，法国国家科学研究中心-雷恩第一大学）；Laboratoire Léon Brillouin（莱昂·布里渊实验室）；Institut des Sciences moléculaires, UMR5255 CNRS – Université de Bordeaux（分子科学研究所，法国国家科学研究中心-波尔多大学）
Capillary rise dynamics of liquid hydrocarbons in mesoporous silica as explored by gravimetry, optical and neutron imaging: Nano-rheology and determination of pore size distributions from the shape of imbibition fronts
The coherent manipulation of acoustic waves on the nanoscale usually requires multilayers with thicknesses and interface roughness defined down to the atomic monolayer. This results in expensive devices with predetermined functionality. Nanoscale mesoporous materials present high surface-to-volume ratio and tailorable mesopores, which allow the incorporation of chemical functionalization to nanoacoustics. However, the presence of pores with sizes comparable to the acoustic wavelength is intuitively perceived as a major roadblock in nanoacoustics. Here we present multilayered nanoacoustic reson…
The lattice dynamics of preferentially aligned nanocrystals formed upon drying of aqueous Ba(NO$_3$)$_2$ solutions in a mesoporous silica glass traversed by tubular pores of approximately 12 nm are explored by Raman scattering. To interpret the experiments on the confined nanocrystals polarized Raman spectra of bulk single crystals and X-ray diffraction experiments are also performed. Since a cubic symmetry is inherent to Ba(NO$_3$)$_2$, a special Raman scattering geometry was utilized to separate the phonon modes of A$_g$ and E$_g$ species. Combining group-theory analysis and \textit{ab initi…
Achieving high power performance and durability with low Pt loadings are critical challenges for proton exchange membrane fuel cells. PtCo catalysts developed on new carbon black supports show promise by simultaneously providing good oxygen reduction kinetics and local oxygen transport. We investigate the role of nanoscale morphology in the performance of these catalysts supported on accessible (HSC-e and HSC-f) and conventional (Ketjen Black) porous carbons using 3D electron tomography, nitrogen sorption, and electrochemical performance measurements. We find that the accessible porous carbons…
We present gravimetrical and optical imaging experiments on the capillarity-driven imbibition of silicone oils in monolithic silica glasses traversed by 3D networks of pores (mesoporous Vycor glass with 6.5 nm or 10 nm pore diameters). As evidenced by a robust square-root-of-time Lucas-Washburn (L-W) filling kinetics, the capillary rise is governed by a balance of capillarity and viscous drag forces in the absence of inertia and gravitational effects over the entire experimental times studied, ranging from a few seconds up to 10 days. A video on the infiltration process corroborates a collecti…
Nanocomposite metal oxide thin films exhibit assuring qualities in the field of gas sensors because of the collective opportunities provided by the heterointerface formation. In this work, we present the synthesis of nitrogen doped mesoporous In$_2$O$_3$-ZnO nano-composite thin films by simple wet chemical method using urea as the nitrogen precursor. SEM investigation suggests formation of mesoporous nano-composite thin films, where the uniformity of surface pore distribution depends on the relative proportion of In$_2$O$_3$ and ZnO in the composites. HRTEM investigation suggest formation of s…
Generalization of Linearized Gouy-Chapman-Stern Model of Electric Double Layer for Nanostructured and Porous Electrodes: Deterministic and Stochastic Morphology
CERIC-ERIC（欧洲同步辐射与中子源研究基础设施联盟）；Institute of Inorganic Chemistry, University of Technology, Graz（格拉茨工业大学无机化学研究所）；Istituto Officina dei Materiali - CNR-IOM（材料研究所-意大利国家研究委员会）；Elettra Sincrotrone Trieste（的里雅斯特电子同步加速器）；Faculty of chemistry and chemical engineering, University of Maribor（马里博尔大学化学与化工学院）；Institute of Physical and Theoretical Chemistry, University of Graz（格拉茨大学物理与理论化学研究所）；Institute of Organic Chemistry, University of Technology, Graz（格拉茨工业大学有机化学研究所）
