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Commercial Pdx(dba)y from various suppliers was found to vary considerably in appearance, homogeneity, purity, and catalytic activity. The Buchwald–Hartwig amination of 4-bromoanisole (5) with anil...

Electrochemical oxidation of biomass substrates to valuable bio-chemicals is highly attractive. However, the design of efficient, selective, stable, and inexpensive electrocatalysts remains challenging. Here it is reported how a 3D highly ordered mesoporous Co

Herein, we present a straightforward surface modification technique for PDMS-based microfluidic devices. The method takes advantage of the high reactivity of concentrated sulfuric acid to enhance the surface properties of PDMS bulk material. This results in alteration of the surface morphology and chemical composition that is in-depth characterized by ATR-FTIR, EDX, SEM, and XPS. In comparison to untreated PDMS, modified substrates exhibit a significantly reduced diffusive uptake of small organic molecules while retaining its low electroosmotic properties. This was demonstrated by exposing the channels of a microfluidic device to concentrated rhodamine B solution followed by fluorescence microscopy. The surface modification procedure was used to improve chip-based electrophoretic separations. Separation efficiencies of FITC-labeled amines/amino acids obtained in treated and untreated PDMS-devices as well as in glass chips were compared. We obtained higher efficiencies in H2 SO4 treated PDMS chips compared to untreated ones but lower efficiencies than those obtained in commercial microfluidic glass devices.

The synthesis of 2,5-dimethylfuran (DMF) from 5-hydroxymethylfurfural (HMF) is a highly attractive route to a renewable fuel. However, achieving high yields in this reaction is a substantial challenge. Here it is described how PtCo bimetallic nanoparticles with diameters of 3.6 ± 0.7 nm can solve this problem. Over PtCo catalysts the conversion of HMF was 100% within 10 min and the yield to DMF reached 98% after 2 h, which substantially exceeds the best results reported in the literature. Moreover, the synthetic method can be generalized to other bimetallic nanoparticles encapsulated in hollow carbon spheres.

The synthesis of yolk–shell catalysts, consisting of platinum or gold–platinum cores and graphitic carbon shells, and their electrocatalytic stabilities are described. Different encapsulation pathways for the metal nanoparticles are explored and optimized. Electrochemical studies of the optimized AuPt, @C catalyst revealed a high stability of the encapsulated metal particles. However, in order to reach full activity, several thousand potential cycles are required. After the electrochemical surface area is fully developed, the catalysts show exceptionally high stability, with almost no degradation over approximately 30 000 potential cycles between 0.4 and 1.4 VRHE.

In cracking from: Highly engineered bifunctional yolk-shell nanocatalysts with tailored structural configuration, that is, hollow carbon spheres as the matrix, entrapped magnetite nanoparticles in the core, and in situ formed and highly dispersed noble metal nanoparticles within the carbon shells as active catalytic sites, were prepared. These nanocatalysts show high activity, reusability, and good magnetic separation properties.

The nanocomposite Co3O4/CoFe2O4 heterostructured mesoporous material was produced via a simple solid–solid reaction of an iron precursor with ordered mesoporous Co3O4 that had been prepared via nanocasting from mesoporous silica as hard template. The magnetic behavior of the exchange-coupled antiferromagnetic/ferrimagnetic (AFM/FM) system was investigated via superconducting quantum interference device (SQUID) magnetometry and 57Fe Mossbauer spectroscopy. The low-temperature magnetization loops of the Co3O4/CoFe2O4 heterostructure present exchange bias under cooling in an applied magnetic field. The antiferromagnetic ordering temperature of Co3O4 is increased due to the proximity of the hard magnetic CoFe2O4 phase. The nanocomposite Co3O4/CoFe2O4 behaves as an exchange coupled system with a cooperative magnetic switching.

Hydrodeoxygenation (HDO) is an attractive route for the upgrading of bio-oils produced from lignocellulose. Current catalysts require harsh conditions to effect HDO, decreasing the process efficiency in terms of energy and carbon balance. Herein we report a novel and facile method for synthesizing bimetallic PtCo nanoparticle catalysts (ca. 1.5 nm) highly dispersed in the framework of nitrogen-doped ordered mesoporous carbon (NOMC) for this reaction. We demonstrate that NOMC with either 2D hexagonal (p6m) or 3D cubic (Im3‾ m) structure can be easily synthesized by simply adjusting the polymerization temperature. We also demonstrate that PtCo/NOMC (metal loading: Pt 9.90 wt %; Co 3.31 wt %) is a highly effective catalyst for HDO of phenolic compounds and "real-world" biomass-derived phenolic streams. In the presence of PtCo/NOMC, full deoxygenation of phenolic compounds and a biomass-derived phenolic stream is achieved under conditions of low severity.

A facile method of coating polystyrene (PS) particles with organo-silica and their functionalization was presented. By adding the organo-silane precursor into PS aqueous solution in presence of ammonia, an organo-silica shell could be coated on PS particles directly. This method has several characteristics. First, only one process, one precursor and one solvent were used. Second, the organic groups could be varied from methyl, propyl, vinyl, to mercaptopropyl. The third is the tunable shell thickness with a high monodispersity. The organo-silica shells are further functionalized. The PS@vinyl-SiO2 particles were used to assemble colloidal crystals, and further modified with bromine, resulting in tunable photonic band gaps. PS@mercaptopropyl-SiO2 particles allow the encapsulation of Au nanoparticles. The resulting 2.2 nm Au particles were stable at 550 °C and well-distributed in the whole SiO2 shell with a loading up to 20 wt%.

UV dye DMT-doped silica films were prepared by sol–gel process with dioxane as the cosolvent. Luminescence quenching was not observed even if the DMT concentration in the visibly transparent silica film is as high as 1.26×10−2 M. The emission peaks centered at ∼375 nm for the films show red-shift of 35–45 nm, comparing with that of the cyclohexane solution of DMT. The fluorescence quantum efficiency of the films centered at ∼590 nm are larger than those at ∼375 nm.

Herein, we present a straightforward surface modification technique for PDMS-based microfluidic devices. The method takes advantage of the high reactivity of concentrated sulfuric acid to enhance the surface properties of PDMS bulk material. This results in alteration of the surface morphology and chemical composition that is in-depth characterized by ATR-FTIR, EDX, SEM, and XPS. In comparison to untreated PDMS, modified substrates exhibit a significantly reduced diffusive uptake of small organic molecules while retaining its low electroosmotic properties. This was demonstrated by exposing the channels of a microfluidic device to concentrated rhodamine B solution followed by fluorescence microscopy. The surface modification procedure was used to improve chip-based electrophoretic separations. Separation efficiencies of FITC-labeled amines/amino acids obtained in treated and untreated PDMS-devices as well as in glass chips were compared. We obtained higher efficiencies in H2 SO4 treated PDMS chips compared to untreated ones but lower efficiencies than those obtained in commercial microfluidic glass devices.

We describe a solid polyphenylene support that serves as an excellent platform for metal-catalyzed reactions that are normally carried out under homogeneous conditions. The catalyst is synthesized by palladium-catalyzed Suzuki coupling which directly results in formation of palladium nanoparticles confined to a porous polyphenylene network. The composite solid is in turn highly active for further Suzuki coupling reactions, including non-activated substrates that are challenging even for molecular catalysts. A major goal in catalysis is to combine the advantages of molecular catalysts and heterogeneous processes, ideally maintaining—or even improving—the reactivity and selectiv- ity of the molecular catalysts, while facilitating product recovery and catalyst recycling. (1-3) However, in fine-chem- icals synthesis molecular catalysts are predominantly used, partly because typical solids do not provide the nonpolar environments often required for organic reactions. This is often easier realized with metal complexes and suitable ligands and solvents, which provide the required geometry and stabilize the transition state of the reaction. (4-6) Polymers as less conventional supports could provide a "solvent"-like reaction environment, onto which ligands and metal com- plexes can be grafted to provide the catalytic functionality. (7, 8) Polymeric solids based on polystyrene, (9, 10) polydivinylben- zene (PDVB), (11) polyacrylate derivatives, (12) covalent organic frameworks (COF), (13) and hybrid metal-organic frame- works (14-16) have recently been explored as carriers for catalytic metal nanoparticles. Commercially, polymeric catalyst supports are limited to ion-exchange resins, for example, the Amberlyst series based on polystyrene-co-divinylbenzene. Also carbon materials are widely applied when an apolar carrier material is required to host metal catalytic species. (17) In our search for intermediate materials between carbons and the polymers listed above, we decided to study the performance of polyphenylene (PPhen) in catalysis. In this polymer, all the carbon atoms are sp 2 hybridized. The thermal and chemical stability of PPhen is higher than those of most other polymers, while it still provides a "solvent-like" reaction environment, suggesting its

Porous carbon monoliths with defined multilength scale pore structures, a nitrogen-containing framework, and high mechanical strength were synthesized through a self-assembly of poly(benzoxazine-co-resol) and a carbonization process. Importantly, this synthesis can be easily scaled up to prepare carbon monoliths with identical pore structures. By controlling the reaction conditions, porous carbon monoliths exhibit fully interconnected macroporosity and mesoporosity with cubic Im3m symmetry and can withstand a press pressure of up to 15.6 MPa. The use of amines in the synthesis results in a nitrogen-containing framework of the carbon monolith, as evidenced by the cross-polarization magic-angle-spinning NMR characterization. With such designed structures, the carbon monoliths show outstanding CO(2) capture and separation capacities, high selectivity, and facile regeneration at room temperature. At ~1 bar, the equilibrium capacities of the monoliths are in the range of 3.3-4.9 mmol g(-1) at 0 °C and of 2.6-3.3 mmol g(-1) at 25 °C, while the dynamic capacities are in the range of 2.7-4.1 wt % at 25 °C using 14% (v/v) CO(2) in N(2). The carbon monoliths exhibit high selectivity for the capture of CO(2) over N(2) from a CO(2)/N(2) mixture, with a separation factor ranging from 13 to 28. Meanwhile, they undergo a facile CO(2) release in an argon stream at 25 °C, indicating a good regeneration capacity.

In situ Fourier transform infrared (FTIR) spectroscopy was employed to characterize the adsorption behavior (as a function of pressure or time) and surface species of CO2 molecules on pure, phosphated, and phosphonated CaO. Carbonate and bicarbonate species were found to form on the pure oxide, whereas on the phosphated and phosphonated oxide samples the carbonate species were found to substitute favorably some of the OH(-) and PO4(3-) groups thereon exposed, respectively. Before and after carbonation, the test samples were further examined by in situ FTIR spectroscopy of adsorbed pyridine species, scanning electron microscopy, and energy dispersive X-ray spectroscopy. Then they were in situ acidified by exposure to a wet atmosphere of HCl vapor at 673 K for 10 min and re-examined similarly to reveal the influence of CO2 adsorption on the chemical and morphological consequences of acidification. The results obtained show the carbonate substitution of PO4(3-) groups to enhance agglomeration of the otherwise fine, longitudinal material particles into much bulkier ones and to render the otherwise more stable phosphonate groups less stable to acid treatment than the phosphate groups. Moreover, the bulky particle agglomerates of the carbonated test samples were detectably eroded following the acid treatment.

A capillary deposition method for the preparation of opal and inverse opal films has been developed. By this method, one can control the film thickness and the crack arrangement in opal as well as inverse opal structures. This method combines tube capillarity with cell capillarity or with gravity depending on the stability of the suspensions. The combination of tube capillarity with cell capillarity is used to prepare opal films from stable suspensions. The tube capillary transports the suspension, while the cell capillary helps to assemble the spheres. The setup defines the drying fronts, thickness, and crack arrangements of the opal films. The combination of capillarity with gravity is useful for making opal films from unstable suspensions. Opal films of spheres with size up to 1 mum can be easily prepared from this combination. Here, the gravity influences the arrangement of the spheres. The two-capillary setup has also been used to infiltrate the opal films with a titania precursor. After calcination, inverse titania opal films with skeleton structure have been obtained.

The growth of α-Al2O3 nanofibers was observed using mesoporous carbon aerogels as substrate and aluminium nitrate as Al2O3 source based on a carbothermal route. The alumina fibers exhibit single crystal characteristics.