Design of a new Ni@NCNT/graphene hybrid structured catalyst for high-performance electrochemical CO reduction: unravelling the roles of N-doping.

Doping strategies have been recognized as effective approaches for developing cost-effective and durable catalysts with enhanced reactivity and selectivity in the electrochemical synthesis of value-added compounds directly from CO. However, the reaction mechanism and the specific roles of heteroatom doping, such as N doping, in advancing the CO reduction reaction are still controversial due to the lack of precise control of catalyst surface microenvironments. In this study, we investigated the effects of N doping on the performances for electrochemically converting CO to CO over Ni@NCNT/graphene hybrid structured catalysts (Ni@NCNT/Gr).

Au@TiO Core-Shell Nanoparticles with Nanometer-Controlled Shell Thickness for Balancing Stability and Field Enhancement in Plasmon-Enhanced Photocatalysis.

Plasmonic core-shell nanostructures can make photocatalysis more efficient for several reasons. The shell imparts stability to the nanoparticles, light absorption is expanded, and electron-hole pairs can be separated more effectively, thus reducing recombination losses. The synthesis of metal@TiO core-shell nanoparticles with nanometer control over the shell thickness and understanding its effect on the resulting photocatalytic efficiency still remains challenging.

Surface modification of mesostructured cellular foam to enhance hydrogen storage in binary THF/H clathrate hydrate.

This study introduces solid-state tuning of a mesostructured cellular foam (MCF) to enhance hydrogen (H) storage in clathrate hydrates. Grafting of promoter-like molecules (, tetrahydrofuran) at the internal surface of the MCF resulted in a substantial improvement in the kinetics of formation of binary H-THF clathrate hydrate. Identification of the confined hydrate as sII clathrate hydrate and enclathration of H in its small cages was performed using XRD and high-pressure H NMR spectroscopy respectively.

Tailored Covalent Organic Framework Platform: From Multistimuli, Targeted Dual Drug Delivery by Architecturally Engineering to Enhance Photothermal Tumor Therapy.

Engineering bulk covalent organic frameworks (COFs) to access specific morphological structures holds paramount significance in boosting their functions in cancer treatment; nevertheless, scant effort has been dedicated to exploring this realm. Herein, silica core-shell templates and multifunctional COF-based reticulated hollow nanospheres (HCOFs) are novelly designed as a versatile nanoplatform to investigate the simultaneous effect of dual-drug chemotherapy and photothermal ablation. Taking advantage of the distinct structural properties of the template, the resulting two-dimensional (2D) HCOF, featuring large internal voids and a peripheral interconnected mesoporous shell, presents intriguing benefits over its bulk counterparts for cancer treatment, including a well-defined morphology, an outstanding drug loading capability (99.

Structured LDH/Bentonite Composites for Chromium Removal and Recovery from Aqueous Solutions.

This study focuses on chromium removal through adsorption and ion exchange using structured calcined layered double hydroxide (LDH) (MgAl)-bentonite composites. Firstly, the powders were structured into granulates to study the effect on Cr sorption kinetics to circumvent the limitations of working with powders in real-life applications. Secondly, the regeneration of the structured composites was optimized to enable multi-cycling operation, which is the key for their applicability beyond laboratory scale.

Recent Trends in Plasmon-Assisted Photocatalytic CO Reduction.

Direct photocatalytic reduction of CO has become an highly active field of research. It is thus of utmost importance to maintain an overview of the various materials used to sustain this process, find common trends, and, in this way, eventually improve the current conversions and selectivities. In particular, CO photoreduction using plasmonic photocatalysts under solar light has gained tremendous attention, and a wide variety of materials has been developed to reduce CO towards more practical gases or liquid fuels (CH , CO, CH OH/CH CH OH) in this manner.

Sunlight-Powered Reverse Water Gas Shift Reaction Catalysed by Plasmonic Au/TiO Nanocatalysts: Effects of Au Particle Size on the Activity and Selectivity.

This study reports the low temperature and low pressure conversion (up to 160 °C, = 3.5 bar) of CO and H to CO using plasmonic Au/TiO nanocatalysts and mildly concentrated artificial sunlight as the sole energy source (up to 13.9 kW·m = 13.

Plasmonic Near-Field Localization of Silver Core-Shell Nanoparticle Assemblies via Wet Chemistry Nanogap Engineering.

Silver nanoparticles are widely used in the field of plasmonics because of their unique optical properties. The wavelength-dependent surface plasmon resonance gives rise to a strongly enhanced electromagnetic field, especially at so-called hot spots located in the nanogap in-between metal nanoparticle assemblies. Therefore, the interparticle distance is a decisive factor in plasmonic applications, such as surface-enhanced Raman spectroscopy (SERS).

Automated discrete electron tomography - Towards routine high-fidelity reconstruction of nanomaterials.

Electron tomography is an essential imaging technique for the investigation of morphology and 3D structure of nanomaterials. This method, however, suffers from well-known missing wedge artifacts due to a restricted tilt range, which limits the objectiveness, repeatability and efficiency of quantitative structural analysis. Discrete tomography represents one of the promising reconstruction techniques for materials science, potentially capable of delivering higher fidelity reconstructions by exploiting the prior knowledge of the limited number of material compositions in a specimen.

Direct-synthesis method towards copper-containing periodic mesoporous organosilicas: detailed investigation of the copper distribution in the material.

Three-dimensional cubic Fm3[combining macron]m mesoporous copper-containing ethane-bridged PMO materials have been prepared through a direct-synthesis method at room temperature in the presence of cetyltrimethylammonium bromide as surfactant. The obtained materials have been unambiguously characterized in detail by several sophisticated techniques, including XRD, UV-Vis-Dr, TEM, elemental mapping, continuous-wave and pulsed EPR spectroscopy. The results show that at lower copper loading, the Cu(2+) species are well dispersed in the Cu-PMO materials, and mainly exist as mononuclear Cu(2+) species.

Asymmetric dyes align inside carbon nanotubes to yield a large nonlinear optical response.

Asymmetric dye molecules have unusual optical and electronic properties. For instance, they show a strong second-order nonlinear optical (NLO) response that has attracted great interest for potential applications in electro-optic modulators for optical telecommunications and in wavelength conversion of lasers. However, the strong Coulombic interaction between the large dipole moments of these molecules favours a pairwise antiparallel alignment that cancels out the NLO response when incorporated into bulk materials.

Probing framework-guest interactions in phenylene-bridged periodic mesoporous organosilica using spin-probe EPR.

The pore walls of phenylene-bridged periodic mesoporous organosilicas (B-PMOs) can be crystal-like or amorphous depending on the synthesis conditions. Here, spin-probe electron paramagnetic resonance (EPR) is used to monitor the adsorption of nitroxide radicals on three types of B-PMO with varying pore size and wall characteristics. Nitroxide radicals with varying polarity are chosen as probes to mimic guest molecules with different properties.

Demonstrating the benefits and pitfalls of various acidity characterization techniques by a case study on bimodal aluminosilicates.

A new combination of a volumetric with a dynamic method to investigate the acidity properties of aluminosilicates is introduced. In the first step, the total acidity is determined volumetrically by the measurement of two-cycle adsorption (TCA) isotherms with ammonia as a probe, directly followed by a dynamic temperature-programmed desorption (TPD) experiment to define the acid strength distribution. Furthermore, the results obtained by the new direct combination of TCA and TPD are validated by comparison with an in-situ FTIR (Fourier transform infrared) study with the same probe molecule on the same materials.

Effects of copper and vanadium deposition in multi-walled hydrogen trititanate and mixed-phase anatase/trititanate nanotubes.

Metal incorporation and doping is one of the routes commonly explored to improve visible light photocatalytic activity of titania and related materials. In this work, we explore the effect of copper and vanadium deposition and incorporation in multi-walled hydrogen trititanate and mixed-phase anatase/trititanate nanotubes. The molecular designed dispersion method is used to introduce the metals in the materials.

Investigation on the low-temperature transformations of poly(furfuryl alcohol) deposited on MCM-41.

MCM-41-type mesoporous silica was used as a support for poly(furfuryl alcohol) deposition. This material was produced by precipitation-polycondensation of furfuryl alcohol (FA) in aqueous slurry of the SiO2 support followed by controlled partial carbonization. By tuning the FA/MCM-41 mass ratio in the reaction mixture, various amounts of polymer particles were introduced on the inner and outer surface of the MCM support.

Controlling pore size and uniformity of mesoporous titania by early stage low temperature stabilization.

The control of the formation process during and after self-assembly is of utmost importance to achieve well structured, controlled template-assisted mesoporous titania materials with the desired properties for various applications via the evaporation induced self-assembly method (EISA). The present paper reports on the large influence of the thermal stabilization and successive template removal on the pore structure of a mesostructured TiO(2) material using the diblock copolymer Brij 58 as surfactant. A controlled thermal stabilization (temperature and duration) allows one to tailor the final pore size and uniformity much more precise by influencing the self-assembly of the template.

New nano-architectures of mesoporous silica spheres analyzed by advanced electron microscopy.

Using template-containing silica microspheres as a precursor, novel ordered mesoporous silica nanoparticles with a narrow pore size distribution and high crystallinity have been synthesized by various hydrothermal merging processes. Several architectures like chains, dumbbells, triangles, squares and flowers have been discovered. The linking mechanisms of these interacting silica spheres leading to the formation of ordered nano-structures are studied by HRTEM, HAADF-STEM and electron tomography and a plausible model is presented for several merging processes.

Synthesis and catalytic applications of combined zeolitic/mesoporous materials.

In the last decade, research concerning nanoporous siliceous materials has been focused on mesoporous materials with intrinsic zeolitic features. These materials are thought to be superior, because they are able to combine (i) the enhanced diffusion and accessibility for larger molecules and viscous fluids typical of mesoporous materials with (ii) the remarkable stability, catalytic activity and selectivity of zeolites. This review gives an overview of the state of the art concerning combined zeolitic/mesoporous materials.

Influence of surfactant concentration on the surface morphology of hollow silica microspheres and its explanation.

The surface morphology of hollow silica microspheres has influence on their applications. After a thorough investigation of the deposition of silica nanoparticles on polystyrene (PS) beads and the surface morphology and texture of the resultant hollow silica shells with scanning electron microscopy, transmission electron microscopy, and N2-sorption measurements, the influence of surfactant [cetyltrimethylammonium bromide (CTAB)] concentration on the surface morphology of hollow silica microspheres templated by PS beads is explained. Previously, CTAB was believed to turn the surface charge of PS beads from negative into positive so that negatively charged silica could be deposited on the PS template.

Immersion calorimetry as a tool to evaluate the catalytic performance of titanosilicate materials in the epoxidation of cyclohexene.

Different types of titanosilicates are synthesized, structurally characterized, and subsequently catalytically tested in the liquid-phase epoxidation of cyclohexene. The performance of three types of combined zeolitic/mesoporous materials is compared with that of widely studied Ti-grafted-MCM-41 molecular sieve and the TS-1 microporous titanosilicate. The catalytic test results are correlated with the structural characteristics of the different catalysts.

Self-assembly and diffusion of block copolymer templates in SBA-15 nanochannels.

Molecular dynamics of triblock copolymers under confinement by the nanochannels of SBA-15 was investigated using pulsed field gradient (PFG) NMR spectroscopy with high-intensity field gradient pulses. The mesoporous material SBA-15 was synthesized using the surfactant Pluronic P123 (EO(20)-PO(70)-EO(20)). The diffusion of P123 in mixtures with water was studied both in bulk and under the condition of confinement by the mesoporous channels of SBA-15.

Direct spectroscopic detection of framework-incorporated vanadium in mesoporous silica materials.

Framework-incorporated vanadium mesoporous silica materials with different contents in vanadium were obtained by a facile, direct synthesis at room temperature, using VOSO4 x 5H2O as the vanadium precursor. The porous characteristics of the samples and the coordination environment of the vanadia in the structure were studied by a combination of techniques: X-ray diffraction, N2-adsorption/desorption, FT-Raman, FTIR-PAS and UV-Vis-DR, electron paramagnetic resonance (EPR) and electron nuclear double resonance (ENDOR) spectroscopy. A structural comparison is made using pulsed EPR and ENDOR spectroscopic techniques between vanadia deposited on the surface of MCM-41 by the Molecular Designed Dispersion method and as-synthesised samples of vanadia incorporated in the mesoporous silica framework using the above-mentioned synthesis method.

Modification of MCM-48-, SBA-15-, MCF-, and MSU-type mesoporous silicas with transition metal oxides using the molecular designed dispersion method.

Four various mesoporous silicas (MCM-48, SBA-15, MCF, and MSU) were modified by the molecular designed dispersion method using Fe(acac)3, Cr(acac)3, and Cu(acac)2 complexes. The deposition was performed at the same concentration of the metal acetylacetonate (acac) complex in a toluene solution. All as-synthesized samples were investigated by diffuse reflectance infrared Fourier transform spectroscopy, Fourier transform infrared photoacoustic spectroscopy, and thermogravimetric analysis.

Anatase formation during the synthesis of mesoporous titania and its photocatalytic effect.

Thermally stable mesoporous titania can be synthesized following different synthesis routes. In this paper, mesoporous titania was synthesized applying the evaporation-induced self-assembly (EISA) method. The mesostructured titania was treated with an NH(4)OH solution to increase the thermal stability.