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Diverse methods have been developed for the synthesis of active nanocatalysts involving various heterogeneous catalytic reactions. Thus far, numerous trial-and-error runs have been done to find the effective and practical ways. In the present work, the All-In-One (AIO) reactor system with a well-designed synthesis program, now in pilot stage, was first exploited as a reliable synthesis tool to find the optimum conditions for the production of Ni nanocatalysts. Using an activated charcoal support, active Ni nanoparticles of 7.8–11.8 nm (labeled A001–A007 in the program) were produced. These were achieved using a melt-impregnation process, which was controlled by variations in the applied gas (N2 and H2) and temperature (400 °C, 450 °C, and 500 °C) used as critical factors in the calcination step. Based on the optimization of the reaction sequence, each Ni nanocatalyst could be prepared within 5 h and 22 min. In particular, the optimum Ni nanocatalyst (A006) with the smallest particle size (7.8 nm), prepared under H2 flow at 400 °C, exhibits the highest catalytic activity (0.748 mmol4-NP·gcat-1·s-1) among the Ni catalysts for 4-nitrophenol (4-NP) reduction to 4-aminophenol (4-AP). This activity is much higher than that of conventional supported Ni nanocatalysts (0.551 mmol4-NP·gcat-1·s-1) produced using the wetness method.

The development of high-performance Ni catalysts including the formation and stabilization of active Ni nanoparticles with high surface areas by increasing their metal dispersion at the high metal loading have been major issues in the design of a compact reformer for hydrogen production. Herein, we first report a facile method based on the sequential melt infiltration process for creating highly dispersed Ni nanoparticles (~7.5 nm) incorporated into alumina support (Ni/Al2O3) with high Ni load (45 wt%). They showed much higher hydrogen productivity and reaction rate than that of the incipient wet-impregnated Ni catalyst and commercial Ni catalyst as well as good thermal stability in steam-methane reforming under harsh conditions.

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).

For the highly productive nanocatalyst synthesis, ensuring the formation and stabilization of active nanoparticles with enlarged surface areas by increasing their metal loading and dispersion have been major issues. Herein, we report a facile method based on a simple melt-infiltration process for creating extremely productive Fe5C2 nanoparticles (∼14 nm) incorporated into graphene flakes (Fe5C2/G) with a stable and high Fe load (∼35 wt%). They showed extremely high C5+ hydrocarbon productivity (4.41 gC5+HC gcat−1 h−1), CO conversion (91.8%), and Fe time yield (6.5 × 10−4 molCO gFe−1 s−1) as well as good thermal stability in CO hydrogenation reactions under harsh conditions.

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.

Improvement of activity, selectivity, and stability of the catalyst used in Fischer-Tropsch synthesis (FTS) to produce targeted hydrocarbon products has been a major challenge. In this work, the potassium-doped iron-carbide/alumina (K-Fe5C2/Al2O3), as a durable nanocatalyst containing small iron-carbide particles (∼ 10 nm), was applied to high-temperature Fischer-Tropsch synthesis (HT-FTS) to optimize the production of linear alpha olefins. The catalyst, suitable under high space velocity reaction conditions (14–36 N L gcat−1 h−1) based on the well-dispersed potassium as an efficient base promoter on the active iron-carbide surface, shows very high CO conversion (up to ∼90%) with extremely high activity (1.41 mmolCO gFe−1 s−1) and selectivity for C5–C13 linear alpha olefins.

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.

Highly-loaded and well-dispersed Fe 5 C 2 nanoparticles within ordered mesoporous carbon CMK-3 (Fe 5 C 2 @CMK-3) were prepared via a simple melt infiltration method. They were successfully applied to high-temperature Fischer-Tropsch synthesis, and showed high CO conversion (91%) and activity (5.1 × 10 −4 mol co g Fe −1 s −1 ) as well as good selectivity (38 wt%) for gasoline-range hydrocarbons (C 5 –C 12 ). The catalytic property of Fe 5 C 2 @CMK-3 was newly interpreted, based on theoretical data obtained by computational simulations.

A small, stationary reformer designed as a stand-alone and self-sustaining type was developed for on-site hydrogen (H2) production. We created a compact reformer to produce H2 at a rate of 1 Nm3/h using the previously reported reaction kinetics of steam methane reforming (SMR). Both catalysts for the compact reformer - i.e., 15 wt% and 20 wt% Ni/γ-Al2O3 - showed good activity, with CH4 conversion exceeding 90% at 655 °C and a contact time of 3.0 gcath/mol, which were considered critical thresholds in the development of a small, compact stationary reformer. At an H2 production rate of 1 Nm3/h, the catalyst amount was calculated to be 167.8 g and the reformer length required to charge the catalyst was 613 mm, with a diameter of 1 inch. The CH4 conversion and H2 production rates achieved with the compact reformer using the 20 wt% Ni/γ-Al2O3 catalyst at 738 °C were 97.9% and 1.22 Nm3/h, respectively. Furthermore, a heat-exchanger type reformer was developed to efficiently carry out the highly endothermic SMR reaction for on-site H2 production. This reformer comprised a tube side (in which the catalysts were charged and the SMR reaction took place by feeding the reactants) and a shell side (in which the heat for the endothermic reaction was supplied by CH4 combustion). Reforming activities were evaluated using the active 20 wt% Ni/γ-Al2O3 catalyst, depending on the reactants' gas hourly space velocity (GHSV). The H2 production rate increased as the GHSV increased. Finally, the reformer produced a CH4 conversion of 98.0% and an H2 production rate of 1.97 Nm3/h at 745 °C, as well as a high reactants' GHSV of 10,000 h−1. Therefore, the heat-exchanger type reformer proved to be an effective system for conducting the highly endothermic SMR reaction with a high reactants' GHSV to yield a high rate of H2 production.

A one-pot synthesis of rose-like Pd–Fe 3 O 4 nanocomposites via the controlled thermal decomposition of Fe(CO) 5 and reduction of Pd(OAc) 2 is reported. This rose-like Pd–Fe 3 O 4 composite structure has a high surface area owing to the individual Pd–Fe 3 O 4 nanosheets, which imparted a high catalytic activity for Sonogashira coupling reactions. Moreover, the catalyst also demonstrated magnetic recyclability.

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*.

To develop small stationary reformers for on-site H 2 production, the active catalyst and its reaction kinetics were examined in order to study the steam methane reforming reaction. A 20 wt% Ni/γ-Al 2 O 3 was found to be a highly active catalyst within the investigated range of contact time from 1.16 to 3.64 g cat h/mol, which was good for developing the small stationary reformers. BET, XRD, and TEM analysis revealed that the high activity of the 20 wt% Ni/γ-Al 2 O 3 catalyst compared to the 15 wt% Ni/γ-Al 2 O 3 catalyst was strongly ascribed to the high number of Ni metal particles and the ratio of the number of the Ni metal species between the catalysts was calculated to be 1.33. Furthermore, the SMR reaction kinetics of the reversible first-order reaction between reactants and products was applied. This showed that the activation energies obtained by the two catalysts were the same because of the similar pore diffusion and heat transfer restrictions, and the similar Ni particle size in the catalyst pores. Also, it was found that the ratio of the pre-exponential factor was 1.30, which was exactly proportional to the ratio of Ni loading in the catalysts because it was strongly related to the collision density.

article i nfo A system consisting of a cobalt catalyst coated metallic foam and heat-exchanger type reactor was developed with the consideration of thesevere heatand masstransferlimitations intheFischer-Tropsch synthesis reaction. The system showed highlydesirableresults notonly interms ofits low CH4and CO2 selectivities, but alsoits high C5+productivity,becauseofitsenhancedheatandmasstransferpropertiesinthereaction.Theeffectsofthesyn- thesis gas flow rate and reaction temperature on the CO conversion and C5+productivity were also investigated. The CO conversion decreased, but the C5+ selectivity increased, with increasing synthesis gas flow rate, because the former was strongly affected by the reaction contact time and the latter was deeply related to the superficial velocity of the synthesis gas in the reactor. Furthermore, this system effectively prevented the formation of CH4, even at high temperature, and reduced the diffusional restrictions of the hydrocarbons produced in the catalyst pores with the temperature. The system of cobalt catalyst coated metallic foam and heat-exchanger type reactor

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.

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.

In a trayed bubble column, the structure of the partitioning plate plays an important role on the bubble behavior. This study examined the effect of the opening ratio and pore size of the plate on the bubble break-up frequency and bubble size distribution. The sieve tray was used as the partitioning plate. The opening ratio was closely related to gas cap development. The stagnation of bubble flow and a gas cap were observed with an opening ratio less than 48.5%. The gas cap increased with decreasing opening ratio and increasing superficial gas velocity. The main effect of the sieve tray could be categorized into the additional drag force and bubble break-up depending on the sieve pore size. When the sieve pore size was smaller than the Sauter diameter of the bubble swarm, the movement of rising bubbles was interrupted by the drag force applied by the surrounding mesh lines. On the other hand, when the sieve pore size was larger than the Sauter diameter, the bubbles were affected by the additional bubble break-up. After the bubbles penetrated the sieve tray, the bubble size distribution shifted to a smaller one and the Sauter diameter decreased.

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.