• Bulletin of the Korean Chemical Society
• /
• v.33 no.5
• /
• pp.1643-1646
• /
• 2012

Three Ni-based catalysts with different clay as support were prepared and tested in the hydrogenation of maleic anhydride, among which Ni/clay1 showed best activity and selectivity. Over Ni/clay1 catalyst prepared by impregnation method, 97.14% conversion of maleic anhydride and 99.55% selectivity to succinic anhydride were obtained at $180^{\circ}C$ under a pressure of 1 MPa. Catalytic activity was greatly influenced by the temperature and weighted hourly space velocity. Catalyst deactivation studies showed that this catalyst have a long life time, the yield of MA still higher than 90% even after a reaction time of 60 h. X-ray diffraction (XRD) and $H_2$ temperature programmed reduction (TPR) were use to investigate the properties of the catalyst. XRD and TPR studies showed that Ni was present as $Ni^{2+}$ on the support, which indicated that there was no elemental nickel ($Ni^0$) and $Ni_2O_3$ in the unreduced samples. The formation of Ni was strong impact on catalytic activity.

• Bulletin of the Korean Chemical Society
• /
• v.34 no.9
• /
• pp.2650-2656
• /
• 2013

Mesoporous alumina was synthesized using bayberry tannin (BT) as template. This novel synthesis strategy was based on a precipitation method associated with aluminum nitrate as the source of aluminum in an aqueous system. $N_2$ adsorption/desorption, XRD, SEM and TEM were used to characterize the as-prepared mesoporous alumina. The results showed that the mesoporous alumina possessed crystalline pore wall, high specific surface area, narrow pore distribution and excellent thermal stability. Moreover, the surface area and pore size of the mesoporous alumina can be tuned by changing the experimental parameters. Further, the mesoporous alumina was investigated as the support of palladium catalyst ($Pd-Al_2O_3{^*}$) for the hydrogenation of propenyl, styrene and linoleic acid. For comparison, the reference catalyst ($Pd-Al_2O_3$) prepared without barberry tannin was also employed for the catalytic hydrogenation. The experimental results showed that $Pd-Al_2O_3{^*}$ exhibited the superior catalytic performance than $Pd-Al_2O_3$ for all the investigated substrates, especially for the hydrogenation of linoleic acid with larger molecular.

• Transactions of the Korean hydrogen and new energy society
• /
• v.22 no.4
• /
• pp.415-423
• /
• 2011

HI decomposition step certainly demand catalytic reaction for efficient production of hydrogen in SI process. Platinum catalyst can apply to HI decomposition reaction as well as hydrogenation or dehydrogenation. Generally, noble metal is used as catalyst which is loaded form for getting high dispersion and wide active area. In this study, Pt was loaded onto zirconia, ceria, alumina, and silica by impregnation method. HI decomposition reaction was carried out under the condition of $450^{\circ}C$, 1atm, and $167.76h^{-1}$ (WHSV) in a fixed bed reactor for measuring catalytic activity. And property of a catalyst was observed by BET, TEM, XRD and chemisoption analysis. On the basis of experimental results, we discussed about conversion of HI according to physical properties of the loaded Pt catalyst onto each support.

• Journal of Korean Society for Atmospheric Environment
• /
• v.15 no.6
• /
• pp.791-797
• /
• 1999

The activity of domestic pigment titania$(TiO_2)$ impregnated with vanadia$(V_2O_5)$ was investigated in the laboratory microreactor. The meta-titanic acid$(TiO(OH)_2)$ which was produced at Hankook Titanium was selected as the precursor for support. The domestic pigment $TiO_2$ showed higher activity in the reduction of NO with $NH_3$ than the foreign commercial $TiO_2$. $WO_3$ were added to domestic $V_2O_5/TiO_2$ catalytic system to improve the catalytic activity at higher reaction temperature between 400~50$0^{\circ}C$ Also, the deactivation of domestic $V_2O_5/TiO_2$ and $WO_3-V_2O_5/TiO_2$ catalyst by $SO_2$ and $H_2O$ was investigated.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2011.08a
• /
• pp.211-211
• /
• 2011

Nanostructures, with a diversity of shapes, built on substrates have been developed within many research areas. Lithography is one powerful, but complex, technique to make structures at the nanometer scale, such as platinum nanowires for studying CO catalytic reactions [1], or aluminum nanodisks for studying the plasmon effect [2]. In this work, we approach a facile method to construct nanostructures using noble metals on a titania thin film by using self-assembled structures as a pattern. Here, a large-scale silica monolayer is transferred to the titania thin film substrates using a Langmuir-Blodgett trough, followed by the deposition of a thin transition metal layer. Owing to the hexagonal close-packed structure of the silica monolayer, we would obtain a metal nanostructure that includes separated metallic triangles (islands) after removing the patterning silica beads. This nanostructure can be employed to investigate the role of metal-oxide interfaces in CO catalytic reactions by changing the patterning silica particles with different sizes or by replacing the oxide support. The morphology and chemical composition of the structure can be characterized by scanning electron microscopy, atomic force microscopy and X-ray photoelectron spectroscopy. In addition, we modify these islands to a connected island structure by reducing the silica size of the patterning monolayer, which is utilized to generating hot electron flow based on the localized surface plasmon resonance effect of the metal nanostructures.

• Journal of the Korean Society of Safety
• /
• v.21 no.2 s.74
• /
• pp.35-45
• /
• 2006

Cobalt catalysts for gas mask loaded on various supports such as $Al_{2}O_{3},\;TiO_{2}$, AC(activated carbon) and $SiO_{2}$ were used to examine influences of calcination temperatures and reaction temperatures for CO oxidation. $Co(NO_{3})_2{\cdot}6H_{2}O$ was used as cobalt precursor and the catalysts were prepared by incipient wetness impregnation. The catalysts were characterized using XRD, TGA/DTA, TEM, $N_{2}$ sorption, and XPS. For the catalytic activity, support was in the order of ${\gamma}-Al_{2}O_{3}>TiO_{2}>SiO_{2}>AC\;and\;Al_{2}O_{3}$. The catalytic activity at lower temperature than $80^{\circ}C$ showed that with the increase of reaction temperature, cobalt catalysts on ${\gamma}-Al_{2}O_{3},\;TiO_{2},\;AC\$ has the negative activation energy but that of $SiO_{2}$ was positive.

• Bulletin of the Korean Chemical Society
• /
• v.31 no.11
• /
• pp.3283-3290
• /
• 2010

The gas-phase dehydration of glycerol to acrolein was carried out over 10 wt % HSiW catalysts supported on different supports, viz. $\gamma-Al_2O_3$, $SiO_2-Al_2O_3$, $TiO_2$, $ZrO_2$, $SiO_2$, AC, $CeO_2$ and MgO. The same reaction was also conducted over each support without HSiW for comparison. Several characterization techniques, $N_2$-physisorption, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), the temperature-programmed desorption of ammonia ($NH_3$-TPD), temperature-programmed oxidation (TPO) with mass spectroscopy and CHNS analysis were employed to characterize the catalysts. The glycerol conversion generally increased with increasing amount of acid sites. Ceria showed the highest 1-hydroxyacetone selectivity at $315^{\circ}C$ among the various metal oxides. The supported HSiW catalyst showed superior catalytic activity to that of the corresponding support. Among the supported HSiW catalysts, HSiW/$ZrO_2$ and HSiW/$SiO_2-Al_2O_3$ showed the highest acrolein selectivity. In the case of HSiW/$ZrO_2$, the initial catalytic activity was recovered after the removal of the accumulated carbon species at $550^{\circ}C$ in the presence of oxygen.

• Transactions of the Korean hydrogen and new energy society
• /
• v.25 no.6
• /
• pp.577-585
• /
• 2014

Nanorod and particle shape $CeO_2$ were synthesized via hydrothermal process and precipitation method, respectively, and used as supports of Pt catalyst for water gas shift (WGS) reaction. Three different durations (12, 48, and 96h) for hydrothermal process were applied for the preparation of nanorod type $CeO_2$. 1.0 wt% of Pt was loaded on the prepared supports with incipient wetness method prior to the catalytic activity tests that were carried out at a GHSV of $95,541h^{-1}$, and a temperature range of 200 to $360^{\circ}C$. Varying duration of hydrothermal process led to the difference in physical characteristics of $CeO_2$ nanorods, such as aspect ratio, BET surface area, pore diameter, and pore volume. Consequently, the catalytic activities of Pt/$CeO_2$ nanorods were affected by the physical characteristics of the supports and appeared to be in the order of Pt/$CeO_2$(12) > Pt/$CeO_2$(48) > Pt/$CeO_2$(96). The comparison of the catalytic activities and results of the analysis (XPS, XRD, SEM, BET and TPR) for the supports revealed that the activity of the catalysts depends on chemical states of the Pt and the support materials in the temperature range that is lower than $280^{\circ}C$. However, the activity is rather dependent on the physical characteristic of the supports because the increased gas velocity limits the mass transfer of reactants in micropores of the supports.

• Clean Technology
• /
• v.15 no.1
• /
• pp.9-15
• /
• 2009

Catalytic hydrodechlorination of PCBs (polychlorinated biphenyls) included in the transformer oil was carried out to detoxify PCBs and to recycle the treated oil. Catalysts such as 0.98 wt% Pt and 0.79 wt% Pd on ${\gamma}$-alumina (${\gamma}-Al_2O_3$) support, 12.8 wt% Ni on ${\gamma}-Al_2O_3$, and 57.6 wt% Ni on silica-alumina ($SiO_2-Al_2O_3$) support were used for the catalytic hydrodechlorination. Various supercritical fluids such as carbon dioxide, propane and isobutane were used as reaction media. The effects of reaction temperature, reaction time, catalysts, and supercritical fluids on the catalytic hydrodechlorination were examined in detail. The detoxification degree increased in the order of Ni > Pd > Pt. This is possibly due to higher metal loading and larger metal size of the Ni catalyst. Below $175^{\circ}C,\;scCO_2$ was found as the most effective reaction media for the catalytic hydrodechlorination of PCBs included in the transformer oil.

• Proceedings of the Materials Research Society of Korea Conference
• /
• 2011.10a
• /
• pp.28.2-28.2
• /
• 2011

The selective catalytic reduction (SCR) of NOx by $NH_3$ is well known as one of the most convenient, efficient, and economical method to prevent NOx emission in flue gas from stationary sources. The degradation of the reactivity is the obstacle for its real application, since high concentrations of sulfur dioxide and thermal factor would deactivate the catalyst. It is necessary to develop high stability of catalysts for low-temperature SCR. Among the transition metal oxides, $WO_3$ is known to exhibit high SCR activity and good thermal stability. The $MnOx-WO_3-TiO_2$ catalysts prepared by sol-gel method with various $WO_3$ contents were investigated for low-temperature SCR. These catalysts were observed in terms of micro-structure and spectroscopy analyses. The $WO_3$ catalyst as a promoter is used to enhance the thermal stability of catalyst since it increases the phase transition temperature of $TiO_2$ support. It was found that the addition of tungsten oxides not only maintained the temperature window of NO conversion but also increased the acid sites of catalyst.