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In this paper, we describe a facile new synthetic method for making highly dispersed molybdenum disulfide nanoparticles (~ 3 nm) on Ketjenblack carbon (MoS2/KC) via particle incorporation and sequential sulfidation. The MoS2/KC nanocatalyst obtained showed a good onset potential value (0.83 V), high durability, and excellent methanol tolerance for the oxygen reduction reaction. We report a simple method for making highly dispersed molybdenum disulfide nanoparticles (~ 3 nm) on Ketjenblack carbon support for sustainable oxygen reduction reactions with good onset potential, high durability, and excellent methanol tolerance.

Bimetallic Rh–Co nanoparticles supported on nitrogen-doped porous carbon (Rh–Co/NPC) were synthesized from metal precursors and urea through a simple thermal decomposition/reduction under a nitrogen flow. The Rh–Co/NPC nanocatalyst which contains highly dispersed alloy nanoparticles (∼6 nm) showed high catalytic performance as well as good recyclability for the C–Se coupling reaction of diphenyl diselenide and aryl boronic acid and p-nitrophenol reduction.

Tin(IV) oxide (SnO2) is the catalyst most commonly used for electrochemical reduction of CO2 into formate. However, the electrocatalytic performance of SnO2 is not ensured due to its poor long-term stability. Here, we report our study on the electrochemical stability of SnO2 for 152 h and describe an approach to achieve stable SnO2 electrodes using a γ-alumina (γ-Al2O3) support. The γ-Al2O3 reduces the leaching of Sn from the supported-SnO2 during CO2 electrolysis due to the strong interaction of the support with the electrocatalyst. This maintains the particle size, morphology, and crystallinity of SnO2. Thereby, pulverization of SnO2 is prevented and stable selectivity towards CO2 reduction results. The prepared SnO2/γ-Al2O3 exhibits much more stable Faradaic efficiency (65.0% at 152 h) and partial current density (21.7 mA cm−2 at 152 h) for formate synthesis than does unsupported SnO2 electrocatalyst (14.2% Faradaic efficiency; 4.6 mA cm−2 of partial current density at 152 h).

The mesoporous hematite cubic frameworks (α-Fe2O3 microcube) with 2–3 μm sizes were prepared using a simple thermal treatment of the iron oxalate hydrate cubes (4 μm). The α-Fe2O3 microcube structure with a high surface area (36 m2 g−1) had three-dimensionally connected small grain sizes (˜18 nm). In formaldehyde (HCHO) gas sensing, the fabricated device by α-Fe2O3 microcubes shows excellent detection ability even at low HCHO concentration (˜50 ppb) and high response reaching to Rgas/Rair = 5.2 at 1 ppm as well as long-term stability, compared with conventional Fe2O3 nanoparticles.

Synthetic methods of mesoporous silica using surfactants or ionic liquids as a template have several disadvantages to commercialization such as low economic feasibility and low sustainability. Thus...

Catalytic reduction by the reverse water gas shift (RWGS) reaction is an efficient way to utilize carbon dioxide and reduce its environmental impact as a greenhouse gas. In this research, an active CuFe/Al 2 O 3 nano powder was developed as a high temperature reforming catalyst for the RWGS reaction. The powder was synthesized by a wet-impregnation method and the copper alloy was uniformly dispersed on the γ-Al 2 O 3 support. At a gas space velocity of 60,000 h −1 , the conversion of carbon dioxide was 42% at 700 °C, which is very close to the equilibrium conversion of 44%. The results indicated excellent reforming activity of the CuFe/Al 2 O 3 catalyst for the high temperature RWGS reaction. In addition, the catalyst was applied in the form of a reforming layer over a conventional Ni-based electrode of a solid oxide electrolysis cell (SOEC) for an integrated SOEC-RWGS system. Hydrogen produced from steam electrolysis over the Ni-based cathode can be efficiently utilized to reduce the carbon dioxide by the RWGS reaction over the CuFe/Al 2 O 3 -based reforming layer. In this bilayer design, the reforming layer maintained the high surface area necessary for achieving good reforming activity, while the electrode layer possessed a high degree of sintering to enhance its electrochemical function. A high conversion of carbon dioxide (37% at 700 °C) was obtained in our bilayer SOEC-RWGS system. This promising result suggests the feasibility of the integrated SOEC-RWGS system for an efficient co-electrolysis device.

Hollow nanomaterials have attracted great interest because of their many applications in catalysis, nanoreactors, drug delivery systems, for lubrication and in gas sensors. Here, carbon sphere templates were prepared from glucose under hydrothermal conditions to facilitate the synthesis of hollow Fe2O3 nanospheres. Thermal decomposition of an iron precursor in benzylalcohol with the carbon spheres resulted in the deposition of Fe3O4 nanoparticles on the carbon sphere templates. The nanoparticles on the carbon surface naturally agglomerate and form a dense oxide shell during the calcination step, which produces typical Fe2O3 hollow structures. The gas sensing performance of the hollow Fe2O3 nanospheres was investigated at an operating temperature of 300 °C. The hollow Fe2O3 nanospheres showed high sensitivity (R = 10.766 at 1 ppm formaldehyde) with a linear response to formaldehyde gas concentration in the range of 0.8~2.4 ppm, and good selectivity to formaldehyde gas in volatile organic compounds, compared to commercial Fe2O3 nanoparticles.

A hierarchical architecture designated as Fe5C2@Ns-rGO/CNT, consisting of carbon nanotubes, steam activated N-doped reduced graphene oxides, and activated iron carbide nanoparticles, was prepared via microwave irradiation and subsequent CO activation. The Fe5C2@Ns-rGO/CNT was successfully applied to a rapid CO hydrogenation reaction showing extremely high activity of 4.4 × 10−3 molCO gFe−1 s−1 at a fast gas velocity of 210 NL gcat−1 h−1.

The production of shape-controlled heterometallic nanoparticles (NPs) consisting of Pt and nonprecious metal oxides is crucial to demonstrate the composition–property relationship of NPs. Herein, we report a facile one-pot approach for the controlled synthesis of dumbbell-like Pt–Fe3O4–MnOx and dendritic Pt–MnOx NPs. The key to the success of this synthesis is in changing the quantity of Fe(CO)5 additive to control the reaction kinetics. In the absence of Fe(CO)5, dendritic Pt–MnOx NPs were synthesized through the assembly of small seed NPs. On the other hand, dumbbell-like Pt–Fe3O4–MnOx NPs were obtained in the presence of Fe(CO)5 through controlling the nucleation and growth of Fe and Mn on the Pt NPs, followed by air oxidation. Compared to a Pt/graphene oxide (GO) catalyst, dumbbell-like Pt–Fe3O4–MnOx NPs on GO showed an enhancement of specific activity toward the oxygen reduction reaction owing to the compressive-strain effect exerted on the Pt lattice.

Nickel-based catalysts have been applied to the catalytic reactions for transfer hydrogenation of carbonyl compounds. In the present work, highly dispersed nickel particles located at the pores of mesoporous silica spheres (Ni@mSiO2) were prepared via an optimized melt infiltration route. The nickel nanoparticles of 10 wt% in the Ni@mSiO2 catalyst could be uniformly loaded with high dispersion of 36.3%, resulting excellent performance for catalytic transfer hydrogenation of aryl ketones.

The high-temperature Fischer–Tropsch synthesis reaction has been exploited to selectively produce lower-olefins and gasoline-range hydrocarbons (C5–C12) from a mixture of carbon monoxide and hydrogen, using iron-based catalysts. For this reaction, improving the selectivity and stability of the catalyst has been a major challenge, as has enhancing the activity. In the present work, we introduce iron-carbide nanoparticles supported on a porous gamma-alumina framework as a robust catalyst, prepared via a simple melt infiltration process and subsequent thermal treatment, for high-temperature Fischer–Tropsch synthesis. The iron-carbide/alumina catalyst showed much better catalytic performance, with a higher stability for producing gasoline-range hydrocarbon products, than did iron-carbide/mesoporous silica (SBA-15) and iron-carbide/activated carbon (AC).

Ordered mesoporous carbon materials are becoming increasingly important in catalysis applications due to their advantageous stability and surface properties. In this paper, we report a replication of the synthesis of mesoporous carbon CMK-3 using SBA-15 as a silica template. Ni/CMK-3 was prepared by incorporating Ni particles formed inside the pores of CMK-3 by impregnation of nickel nitrate and subsequent hydrogen reduction. The prepared Ni/CMK-3 has a large surface area and a very small nickel nanoparticle size (1 nm) with the aim of achieving high performance in catalytic hydrogenation reactions. Moreover, we demonstrate that CMK-3 has a higher stability than that of SBA-15 during the hydrogenation reactions of acetophenone derivatives.

Magnetite (Fe3O4) nanoparticles supported on charcoal, graphene, or SBA-15 were prepared by a simple solid-state grinding technique and subsequent thermal treatment. The Fe3O4 nanoparticles supported on activated charcoal exhibited high catalytic activity and furnished good yields of the alkynyl selenide product in the cross-coupling reaction of diphenyl diselenide and alkynes through activation of C−H and Se−Se bonds under ecofriendly conditions, surpassing traditional copper-based catalysts to effect the same organic transformation.

Temperature-programmed reduction using H2 (H2-TPR) and CO (CO-TPR) was carried out to investigate the reduction and carburization behavior of nanocrystalline ferrihydrite-based Fe/Cu/K/SiO2 catalysts for use in Fischer-Tropsch synthesis (FTS). Unlike pure ferrihydrite, the ferrihydrite-based catalysts did not pass through the intermediate decomposition step of ferrihydrite (Fe9O2(OH)23) into hematite (a-Fe2O3) as they were reduced into magnetite (Fe3O4). This is attributed to the enhanced thermal stability induced by SiO2. For the ferrihydrite-based catalysts, the reduction of ferrihydrite into magnetite occurred in two stages because the reduction promoter, Cu, is not homogeneously distributed on the catalyst surfaces. The Cu-rich sites are likely to be reduced in the first stage, and the Cu-lean sites may be reduced in the second stage. After the ferrihydrite is reduced to magnetite, the reduction process of magnetite was similar to that for conventional hematite-based FTS catalysts: 'magnetite --> metallic iron' and 'magnetite --> wustite (FeO) or fayalite (Fe2SiO4) --> metallic iron' in the H2 atmosphere; 'magnetite --> iron carbides' in the CO atmosphere.

This study investigated the effect of impregnating Ba into an Al2O3 catalyst on the acid-base property and catalytic activity in the dehydration of 1-octanol to produce 1-octene. The Ba/Al2O3 catalysts were prepared by the incipient wetness method with different Ba contents of 0.0–3.0 wt%, and characterized by ICP-MS, BET-BJH, XRD, pyridine-FTIR, and CO2-TPD. The catalytic activity in 1-octanol dehydration was evaluated at 300, 350, and 400 °C with liquid hourly space velocity (LHSV) of 7–56 h−1. As the amount of Ba increased, the density of the basic site on Ba/Al2O3 increased, and the strength distribution of the Lewis acid site (LAS) was changed. Under the reaction condition of 400 °C and LHSV = 7 h−1, Ba/Al2O3 showed higher 1-octene selectivity and 1-octene purity compared with the pure Al2O3 even though the 1-octanol conversion was similar. This is because the added Ba eliminated the strong LAS, which, in turn, inhibited the side-reaction originating from the re-adsorption of 1-octene. When LHSV > 21 h−1, Ba/Al2O3 catalysts showed decreased 1-octanol conversion but maintained high 1-octene selectivity and 1-octene purity. As the Ba content reached 2.0 wt%, 1-octene selectivity was decreased as the formation of dioctyl ether became more active than olefin production. Therefore, 1.5 wt% Ba/Al2O3 is the optimal catalyst for producing 1-octene from 1-octanol in terms of 1-octanol conversion, 1-octene selectivity, and 1-octene yield.

To upgrade odd numbered α-olefins derived from FTS residues, the heterogeneous hydroformylation of 1-heptene as a model compound for odd numbered α-olefin was investigated. Single crystalline Co3O4 nano catalysts with different morphologies (cube and octahedron) were synthesized using a hydrothermal method and were applied to the reductive hydroformylation of 1-heptene. HRTEM and SEM analysis indicated that the cubic and octahedral Co3O4 predominantly exposed well-defined crystal planes of {100} and {111}, respectively. The Co3O4 octahedron catalyst with highly exposed {111} facets had higher activity for hydroformylation than the Co3O4 cube catalyst. The Co3O4 octahedron catalyst with a {111} surface was easily reduced to CoO at lower temperature. These reduced cobalt species can be converted into cobalt carbonyl and improved reactivity with carbon monoxide, hydrogen and olefin, leading to better catalytic performance for hydroformylation than Co3O4. On the other hand, the Co3O4 cube catalyst with the {100} surface only exhibited the isomerization of 1-heptene.

Mo2C/graphene nanostructures were used to investigate the nature of gas-phase formic acid decomposition into either CO/H2O or CO2/H2 products. The experimental data show that the Mo2C/graphene can facilitate both decarboxylation and dehydration pathways for the formic acid decomposition reaction. Its selectivity is strongly influenced by the reaction temperature where the decarboxylation predominates at a low temperature (e.g., ≤ 280 °C) and the dehydration predominates at a high temperature (e.g., ≥ 370 °C). These experimental data are compared to Monte Carlo simulations. It was found that the decarboxylation pathway for the production of CO/H2O can be simulated and explained by an Eley-Rideal type mechanism that involves interaction of gas-phase HCOOH with surface H*. Furthermore, the dehydration pathway for the production of CO2/H2 can be simulated and explained by a Langmuir-Hinshelwood type mechanism that involves unimolecular decomposition of surface HCO*O* to form CO2 and H*.

A facile synthetic strategy for a hybrid Cu2O/Pd–Fe3O4 nanocomposite via controlled thermal decomposition of Fe(CO)5 and reduction of Pd(OAc)2 and Cu(acac)2 was developed. The Pd precursor and amount of reducing agent used during the synthetic process controlled the morphology of the Cu2O/Pd–Fe3O4 nanocomposites. The prepared Cu2O/Pd–Fe3O4 nanocomposites showed excellent catalytic performance for C–H arylation, which can be attributed to the synergetic catalytic system formed from the catalytically effective Pd and Cu2O. Moreover, to the best of our knowledge, the C–H arylation of 4-nitroimidazoles with aryl iodides catalyzed by heterogeneous nanocatalysts has not been reported in the literature.

Combined high catalytic activity and thermal stability were achieved with a well-structured, surfactant-free Pd@porous SiO2 yolk–shell nanostructure, resulting from the entirely exposed Pd core particles and highly porous silica shells. Pd@SiO2 core–shell nanoparticles were synthesized by a water-in-oil microemulsion method for direct silica coating of as-prepared tiny Pd nanoparticles. Hydrothermal etching and subsequent high thermal treatment generated large pores in the silica shells and facilitated complete removal of surfactants around the core particles. The surfactant-free Pd@pSiO2 yolk–shell nanoparticles efficiently catalyzed the oxidation of benzyl alcohol as well as that of various substituted benzyl alcohols.

Fresh catalyst samples of 100Fe/5.26Cu/4.76K/18.2SiO2 in part per weight were synthesized by using a combination of a co-precipitation technique and spray-drying method and were activated in situ by using syngas (H2/CO/xCO2) with different amounts of CO2 (x = 0.0, 0.5, 1.0, and 2.0). All activated catalyst samples showed similar XRD patterns, a combination of ferrihydrite, magnetite, χ-carbide, and e′-carbide, regardless of the CO2 contents. From the Mossbauer spectra, we also observed a combination of ferrihydrite, magnetite, χ-carbide, and e′-carbide in all activated catalyst samples. The main compound of the activated catalyst sample activated by using CO2-free syngas (H2/CO) was magnetic χ-carbide, and the main compound changed from χ-carbide to ferrihydrite with increasing CO2 concentration, confirmed by both, Mossbauer spectra and XRD pattern.

We developed a photocatalyst (T–FC) that incorporated anatase TiO2 (T) nanoparticles on magnetically enhanced carbon [iron oxide (F; α,γ-Fe2O3–Fe3O4) supported on activated carbon (C)] for use as a highly visible-light-active, low-cost, recyclable, and photostable catalyst for the degradation of organic dyes and bacterial sterilization. The T–FC photocatalyst with a large Brunauer–Emmett–Teller surface area (564.3 m2 g−1) was synthesized by wet-chemical processing and ultrasound irradiation. Under visible-light irradiation, the highest photocatalytic activity for T–FC ([k] = 3.874 h−1) was 32.6 and 3.1 times higher than those of T ([k] = 0.119 h−1) and FC ([k] = 1.259 h−1). The recyclability of T–FC was high, with a dye decolorization rate measured at ∼95.8% of the initial value after 15 recycles. Furthermore, T–FC showed more substantial antimicrobial properties against both Gram-negative Escherichia coli (E. coli) and Gram-positive Staphylococcus aureus (S. aureus) than T and FC when exposed to visible-light for 120 min. Even after 10 cycles of use, T–FC killed more than 95.7% of E. coli. These results indicated that T–FC might have utility in several promising applications such as wastewater treatment and as a bactericidal agent.

This paper reviews recent developments in the field of hybrid Pd nanoparticles and their catalytic activity in the Suzuki coupling reaction, which is used extensively in the fabrication of both simple and complex biaryl compounds. We developed three types of Pd-silica hybrid nanoparticles. Pd/SiO2 nanobeads containing tiny Pd clusters, Pd@nickel phyllosilicate yolk-shell nanoparticles, Pd@porous SiO2 yolk-shell nanoparticles were synthesized, and they displayed highly efficient catalytic activity and excellent reusability. The hybrid nanoparticles also catalyzed the Suzuki coupling reaction with various substrates, including bromobenzene and chlorobenzene. This review also briefly discusses the synthesis procedure, structural characterization, and catalytic activity of hybrid Pd nanoparticles.

The linear α-olefin 1-octene was produced via the dehydration of 1-octanol over Al2O3 catalysts. The effect of calcination temperature on the characteristics of an Al2O3 catalyst and its activity in the dehydration of 1-octanol to 1-octene was investigated. Al2O3 catalysts calcined at various temperatures (250, 500, 750, 1000 °C) were evaluated at 300–400 °C with a liquid hourly space velocity (LHSV) of 7–56 h−1. XRD, BET, 27Al-NMR, Py-FTIR, and NH3-TPD analyses indicated that the calcination temperature affected the crystal phase, surface area, occupancy of the coordinated Al3+ ion, and acidic properties of Al2O3 catalysts. Upon calcination at temperatures >750 °C, the surface area of Al2O3 catalysts reduced due to γ-Al2O3 to θ-Al2O3 phase transition. The changes in the crystal phase decreased the surface area, which correlated to the acidity of the Al2O3 catalyst. The distribution of unsaturated Al3+ ions acting as LAS on the catalyst surface increased with increasing calcination temperature, but decreased above 750 °C calcination temperature due to the diminishing surface area. The Al2O3 catalyst calcined at 500 °C showed the highest 1-octanol conversion in the dehydration of 1-octanol. High 1-octene selectivity was maintained while the isomer ratio decreased at a high LHSV of 56 h−1.

The use of nanostructure materials as heterogeneous catalysts in the synthesis of organic compounds have been receiving more attention in the rapid developing area of nanotechnology. In this review, we mainly focused on our own work on the synthesis of hybrid palladium−iron oxide nanoparticles. We discuss the synthesis of Pd−Fe3O4—both morphology-controlled synthesis of Pd−Fe3O4 and transition metal-loaded Pd−Fe3O4—as well as its application in various C−C coupling reactions. In the case of rose-like Pd−Fe3O4 hybrid nanoparticles, thermal decomposition can be used instead of oxidants or reductants, and morphology can be easily controlled. We have developed a method for the synthesis of nanoparticles that is facile and eco-friendly. The catalyst was recyclable for up to five continual cycles without significant loss of catalytic activity and may provide a great platform as a catalyst for other organic reactions in the near future.

In the present work, we synthesized magnetically separable Pd/Fe3O4/charcoal nanocatalysts by simple solid-state grinding of a mixture of salts and the simultaneous thermal decomposition of the salts. The highly loaded Pd nanoparticles (20 wt%) were well dispersed in the porous charcoal, with an average diameter of ∼5 nm and clean surfaces without any surfactant. Moreover, the simultaneously obtained Fe3O4 nanoparticles (10 wt%) had good superparamagnetic character, enabling quick separation of the catalyst from the products and re-dispersion in the reaction solution. The bifunctional catalyst showed a high product time yield with various substituted aryl halides and aryl boronic acids.

Fischer–Tropsch synthesis was carried out over industrially important Fe/Cu/K/SiO2 catalysts containing a small amount of residual sodium which originated from the sodium carbonate solution used as a precipitating agent. The structural promoter, SiO2, was incorporated by two comparative sequences: immediately after precipitation (AP) or after a subsequent wash (AW). Whereas AW exhibited severe deactivation during the reaction, AP displayed high and stable catalytic activity for the entire reaction time. Furthermore, AP showed higher selectivity of liquid hydrocarbons, in particular heavy hydrocarbons, than AW. We attribute the advantageous catalytic performance observed in AP to the enhanced reducibility and higher surface basicity of AP, potentially induced by higher dispersion of catalysts and promoters.

Recent developments in the synthesis of SpellECuO nanoparticles (NPs) and their application to the [3+2] cycloaddition of azides with terminal alkynes are reviewed. With respect to the importance of click chemistry, CuO hollow NPs, CuO hollow NPs on acetylene black, water-soluble double-hydrophilic block copolymer (DHBC) nanoreactors and ZnO–CuO hybrid NPs were synthesized. Non-conventional energy sources such as microwaves and ultrasound were also applied to these click reactions, and good catalytic activity with high regioselectivity was observed. CuO hollow NPs on acetylene black can be recycled nine times without any loss of activity, and water-soluble DHBC nanoreactors have been developed for an environmentally friendly process.

Pd/SiO2 nanobeads containing tiny Pd clusters with a diameter of about 2 nm were prepared via a sol–gel process for SiO2 by using a water-in-oil microemulsion with Pd complexes and subsequent hydrogen reduction by heat treatment. The Pd/SiO2 nanostructures were employed in Suzuki coupling reactions with various substrates, and they served as good catalysts in these reactions.

The pre-reforming of higher hydrocarbon, propane, was performed to generate hydrogen from LPG without carbon deposition on the catalysts. A Ru/Ni/MgAl2O4 metallic monolith catalyst was employed to minimize the pressure drop over the catalyst bed. The propane pre-reforming reaction conditions for the complete conversion of propane with no carbon formation were identified to be the following: space velocities over 2400 h−1 and temperatures between 400 and 450 °C with a H2O/C1 ratio of 3. The combined pre-reformer and the main reformer system with the Ru/Ni/MgAl2O4 metallic monolith catalyst was employed to test the conversion propane to syngas where the reaction heat was provided by catalytic combustors. Propane was converted in the pre-reformer to 52.5% H2, 27.0% CH4, 17.5% CO, and 3.0% CO2 with a 331 °C inlet temperature and a 482 °C catalyst outlet temperature. The main steam reforming reactor converted the methane from the pre-reformer with a conversion of higher than 99.0% with a 366 °C inlet temperature and an 824 °C catalyst outlet temperature. With a total of 912 cc of the Ru/Ni/MgAl2O4 metallic monolith catalyst in the main reformer, the H2 production from the propane reached an average of 3.25 Nm3h−1 when the propane was fed at 0.4 Nm3h−1.

The clinical significance of ADAMTS13 activity for response to treatment, mortality rate, recurrence, and prognosis is unclear. Therefore, we investigated the characteristics of severe ADAMTS13 deficiency and evaluated its prognostic features in Thrombotic thrombocytopenic purpura (TTP). The Korean TTP Registry includes 66 patients from 13 teaching hospitals in Korea who received the diagnosis of TTP from January 2005 to December 2008. Blood samples obtained upon admission were sent for ADAMTS13 analysis (multimer analysis by sodium dodecyl sulfate electrophoresis) to a central laboratory along with patient clinical information. Patients with severe ADAMTS13 deficiency had lower serum creatinine levels (P = 0.001) than patients with non-severe ADAMTS13 deficiency. Although severe ADAMTS13 deficiency was associated with better response rate (75 vs. 53%, P = 0.145), remission rate (81 vs. 61%, P = 0.209), and mortality rate (19 vs. 31%, P = 0.508) than non-severe ADAMTS13 deficiency, treatment outcomes did not differ significantly between groups. After adjusting for clinical and laboratory features, multivariate analysis did not reveal any independent risk factors for TTP-associated mortality. Patients with severe ADAMTS13 deficiency had lower serum creatinine levels at presentation, but severe ADAMTS13 activity deficiency at TTP diagnosis does not appear to have prognostic significance.

tion is not particularly effective in the samples that have small metal cores. These difficulties have hindered the large scale synthesis of yolk-shell-type catalyst structures. Herein, we demonstrated that a Co@SiO2 yolk-shell nanostructure was an excellent target for large scale synthesis by a simple treatment. As shown in Scheme 1, we fabricated CoO@SiO2 core-shell nanoparticles at first and converted them Co@SiO2 yolk-shell nanostructures were fabricated on a gram scale by simple hydrogen reduction of CoO@SiO2 core-shell nanoparticles without using an etching step. The cobalt core diameters were reduced by the lattice volume contraction of CoO to Co, forming vacancy between the cores and the silica shells. The Co@SiO2 yolk-shell nanocatalysts were employed for the phenoxycarbonylation of iodobenzene, and exhibited high activity and reusability. The magnetic property of the cobalt cores enabled the facile separation of catalysts from the products.

Recent developments in nanochemistry offer precise morphology control of nanomaterials, which has significant impacts in the field of heterogeneous catalysis. Rational design of bifunctional catalysts can influence various aspects of catalytic properties. In this review, a new class of bifunctional catalysts with a metal@silica yolk-shell nanostructure is introduced. This structure has many advantages as a heterogeneous catalyst since it ensures a homogeneous environment around each metal core, and particle sintering is effectively eliminated during high temperature reactions. The catalysts exhibit high activity and recyclability in gas- and solution-phase reactions. It is anticipated that appropriate selection of bifunctional components and optimal structural control will significantly further enhance the catalytic properties, and enable target reaction-oriented development of new catalysts.

CuO hollow nanospheres on acetylene black (CuO/AB) have been used for the catalytic [3 + 2] cycloaddition of azides with terminal alkynes without solvent, and within 1 min under microwave irradiation. The CuO/AB was readily separated by centrifugation, and could be reused five times under the present reaction conditions without any loss of catalytic activity.

In the present work, we report the synthesis of Ni@SiO2 yolk−shell nanocatalysts that bear tiny nickel cores with an average diameter of 3 nm. The nickel nanoparticles were coated with silica through the microemulsion method, and the resulting Ni@SiO2 core−shell nanoparticles were partially etched by acid treatment. The calcination of the particles yielded yolk−shell nanocatalysts with a uniform structure. The catalysts were employed for heterogeneous hydrogen-transfer reactions of acetophenone. The optimized reaction condition used 0.03 mol % of the catalysts in the presence of 20 mol % of base at 423 K for 30 min. Under this condition, the conversion reached 90%, and the TOF was calculated to be 6000 h−1, which is at least 60 times higher than the previous results using nickel catalysts. The catalysts were highly stable and more than six times recyclable without any loss of catalytic activity. This rational yolk−shell design of the nanocatalysts can be employed for various organic reactions with the adv...

Nickel-based catalysts have been good candidates for steam reforming of methane, but their stability has been restricted due to the agglomeration among particles at high temperature. In the present work, a new type of Ni@SiO2 yolk-shell nanoreactor framework comprising Ni cores inside hollow silica shells has been prepared through direct silica coating and subsequent selective etching of the metal cores. This nanoreactor framework is remarkably stable at high temperatures up to 973 K, because the silica hollow shells around the nickel cores essentially block particle sintering. The Ni@SiO2 nanoreactor structure is employed as a model catalyst for the steam methane reforming reaction. The catalysts exhibit a continuous conversion rate of methane and hydrogen, and significantly enhanced stability at high temperatures, leading to high recyclability without loss of catalytic activity. These reaction properties are superior to Ni/MCF catalysts, and comparable with state-of-the-art commercial catalysts. This catalyst design can be generalized for other bifunctional systems, such as Co@SiO2 and Fe@SiO2.

CuO/AB was found to be a simple and efficient catalyst for the N-arylation of a variety of nitrogen-containing heterocycles, giving the products in excellent yields.

Thermal and air-stable uniform Cu2O nanocubes were employed in the development of a gram-scale, one-pot polyol synthesis. Herein is reported an efficient cross-coupling reaction of aryl halides and phenols with a catalytic amount (0.1 mol-%) of Cu2O nanocubes as recyclable catalyst and Cs2CO3 as the base in THF at 150 °C. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)

Nanoreactor frameworks have many advantages over bulk catalyst structures in terms of providing a regular reaction environment and conformational stability. In this work, Au@SiO2 nanoreactor frameworks were chemically modified to improve the catalytic efficiency of o-nitroaniline reduction. The porosity of silica shells was readily controlled by introducing C18TMS as a porogen with heat treatment. The diffusion rate of the silica layers was tuned from 5.9 × 10−19 to 2.1 × 10−18 m2 s−1, which directly altered the turnover frequency and rate constant of the reaction. Carboxylate functionality was introduced on the gold cores of Au@SiO2 nanoreactors by 3-MPA addition. The reaction rate was enhanced by a maximum of 2.4 times compared to unfunctionalized catalysts through a strong interaction between carboxylate anions and o-nitroaniline. Totally, the rate constant of Au@SiO2 yolk−shell nanoreactors exhibits a 13-fold enhancement by diffusion and surface functionality control. These results indicate that the r...

Accordingly,the interactions between metal nanoparticles and supportsshould be precisely manipulated in order to maximize theirsynergetic effects. Metal particles should be dispersed evenlyon the supports in order to prevent aggregation betweenparticles in close proximity, and to maintain metal–supportcontact areas. Numerous processes have been developed foreffective dispersion of metal nanoparticles in bifunctionalcatalysts.

The development of easier, cheaper and more ecofriendly synthetic methods for mesoporous materials remains a challenging topic to commercialize them and the transformation of waste glycerol, as a biodiesel byproduct, into something useful and salable is one of the pending issues to be resolved. Here we first report that mesoporous silica (KIE-6) and carbon (KIE-7) can be simultaneously synthesized by using cheap and ecofriendly crude-waste-glycerol of biodiesel with or without glycerol purification and we demonstrated the excellent performance of the mesoporous material as a catalyst support for formic acid decomposition. As a result, Pd-MnOx catalysts supported on NH2-functionalized KIE-6 showed the highest catalytic activity (TOF: 540.6 h−1) ever reported for room-temperature formic acid decomposition without additives. Moreover, we conducted life-cycle assessment (LCA) from biomass cultivation through biodiesel production to KIE-6 and KIE-7 preparation and it was confirmed that CO2 emission during synthesis of KIE-6 and KIE-7 could be reduced by 87.1% and 85.7%, respectively. We believe that our study suggested more ecofriendly and industry-friendly approaches for preparation of mesoporous materials and utilization of waste glycerol.

We report the shape and size control of polyhedral gold nanocrystals by a modified polyol process. The rapid reduction of gold precursors in refluxing 1,5-pentanediol has successfully provided a series of gold nanocrystals in the shape of octahedra, truncated octahedra, cuboctahedra, cubes, and higher polygons by incremental changes of silver nitrate concentration. All nanocrystals were obtained quantitatively and were uniform in shape and size in the range of approximately 100 nm. Smaller octahedra and cubes were also prepared by using large amounts of PVP. Silver species generated from AgNO3 seemed to determine the final nanocrystal morphology by the selective growth of {111} and/or the restriction of {100}. The shape evolution of the particles was addressed by quenching the reactions at different time intervals. The approximately 60 nm seeds were generated rapidly and grown slowly with simultaneous edge sharpening. Aging the reaction mixture focused the size and shape of the nanocrystals by Ostwald ripening. We believe that our selective growth conditions can be applied to other shapes and compositions of face-centered cubic metals.

This paper reviews recent developments in the field of hybrid Pd nanoparticles and their catalytic activity in the Suzuki coupling reaction, which is used extensively in the fabrication of both simple and complex biaryl compounds. We developed three types of Pd-silica hybrid nanoparticles. Pd/SiO2 nanobeads containing tiny Pd clusters, Pd@nickel phyllosilicate yolk-shell nanoparticles, Pd@porous SiO2 yolk-shell nanoparticles were synthesized, and they displayed highly efficient catalytic activity and excellent reusability. The hybrid nanoparticles also catalyzed the Suzuki coupling reaction with various substrates, including bromobenzene and chlorobenzene. This review also briefly discusses the synthesis procedure, structural characterization, and catalytic activity of hybrid Pd nanoparticles.

New functionalized CuO hollow nanospheres on acetylene black (CuO/AB) and on charcoal (CuO/C) have been found to be effective catalysts for C-S bond formation under microwave irradiation. CuO catalysts showed high catalytic activity with a wide variety of substituents which include electron-rich and electron-poor aryl iodides with thiophenols by the addition of two equivalents of K2CO3 as base in the absence of ligands.

Recent developments in the synthesis of CuO nanoparticles (NPs) and their application to the [3+2] cycloaddition of azides with terminal alkynes are reviewed. With respect to the importance of click chemistry, CuO hollow NPs, CuO hollow NPs on acetylene black, water-soluble double-hydrophilic block copolymer (DHBC) nanoreactors and ZnO–CuO hybrid NPs were synthesized. Non-conventional energy sources such as microwaves and ultrasound were also applied to these click reactions, and good catalytic activity with high regioselectivity was observed. CuO hollow NPs on acetylene black can be recycled nine times without any loss of activity, and water-soluble DHBC nanoreactors have been developed for an environmentally friendly process.

ZnO—CuO core—branch hybrid nanoparticles are synthesized and applied as highly active heterogeneous catalyst in the title reaction.

Recent developments in nanochemistry offer precise morphology control of nanomaterials, which has significant impacts in the field of heterogeneous catalysis. Rational design of bifunctional catalysts can influence various aspects of catalytic properties. In this review, a new class of bifunctional catalysts with a metal@silica yolk-shell nanostructure is introduced. This structure has many advantages as a heterogeneous catalyst since it ensures a homogeneous environment around each metal core, and particle sintering is effectively eliminated during high temperature reactions. The catalysts exhibit high activity and recyclability in gas- and solution-phase reactions. It is anticipated that appropriate selection of bifunctional components and optimal structural control will significantly further enhance the catalytic properties, and enable target reaction-oriented development of new catalysts.

An approach for gram-scale synthesis of uniform Cu2O nanocubes by a one-pot polyol process was used. The CuO hollow nanostructures were prepared by adding aqueous ammonia solutions with Cu2O nanocube colloidal solutions. CuO hollow nanospheres on acetylene black (CuO/AB), were synthesized and used for the catalytic [3 + 2] cycloaddition of azides with terminal alkynes to provide products in good yields with high regioselectivity. The CuO/AB was readily separated by centrifugation and could be reused ten times under the present reaction conditions without any loss of catalytic activity. Transition metals loaded onto acetylene black are useful reagents for a wide variety of organic transformations. Moreover, these heterogeneous systems are promising industrial catalysts.

To investigate the efficacy and safety of combination chemotherapy with biweekly paclitaxel plus infusional 5-fluorouracil and leucovorin in the treatment of patients with advanced or metastatic gastric cancer.Chemonaive patients with histologically confirmed advanced or recurrent inoperable gastric cancer were enrolled in the present study. Treatment consisted of paclitaxel (75 mg/m(2)) and leucovorin (40 mg/m(2)) as a 2-h intravenous infusion, followed by 5-fluorouracil (2,400 mg/m(2)) as a 46-h continuous infusion. Cycles were repeated every 2 weeks.Thirty patients were enrolled in this study. There were 12 partial responses, giving an overall response rate of 40.0%. At a median follow-up of 10.6 months, the median time to progression and median overall survival were 3.9 and 8.8 months, respectively. The most common hematological toxicity was grade 1-2 anemia, which was seen in 83.3% of patients. No grade 4 leukopenia, thrombocytopenia, or anemia was noted. The most common non-hematological toxicity was anorexia, which was seen in 70% of patients, although grade 3 anorexia was noted in only 10% of cases. There was no severe treatment-related morbidity or death.Combination chemotherapy consisting of biweekly paclitaxel plus infusional 5-fluorouracil and leucovorin was effective and well tolerated in patients with advanced gastric cancers.

Metal nanoparticles whose sizes are between those of bulk and monomeric metal species have a wide range of applications; such nanoparticles are used in various electronic, optical, and magnetic devices as well as in the production of catalytic ma-terials. Transition-metal nanoparticles are an important class of catalysts used in organic synthesis.

ZnO-CuO core-branch hybrid nanoparticles, synthesized by copper oxide growth and controlled oxidation on ZnO nanospheres, exhibited remarkable enhancement of catalytic activity and stability for ultrasound-assisted [3+2] azide-alkyne cycloaddition reactions, due to their high surface area and active facets of the CuO branches.