NiO 촉매의 분산성 및 안정성 향상을 위하여 FeCrAl 합금 폼 위에 성장된 Al₂O₃ Inter-Layer 효과

이유진,구본율,백성호,박만호,안효진,Lee, Yu-Jin,Koo, Bon-Ryul,Baek, Seong-Ho,Park, Man-Ho,Ahn, Hyo-Jin 한국재료학회 2015 한국재료학회지 Vol.25 No.8

NiO catalysts/$Al_2O_3$/FeCrAl alloy foam for hydrogen production was prepared using atomic layer deposition (ALD) and subsequent dip-coating methods. FeCrAl alloy foam and $Al_2O_3$ inter-layer were used as catalyst supports. To improve the dispersion and stability of NiO catalysts, an $Al_2O_3$ inter-layer was introduced and their thickness was systematically controlled to 0, 20, 50 and 80 nm using an ALD technique. The structural, chemical bonding and morphological properties (including dispersion) of the NiO catalysts/$Al_2O_3$/FeCrAl alloy foam were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, field-emission scanning electron microscopy and scanning electron microscopy-energy dispersive spectroscopy. In particular, to evaluate the stability of the NiO catalysts grown on $Al_2O_3$/FeCrAl alloy foam, chronoamperometry tests were performed and then the ingredient amounts of electrolytes were analyzed via inductively coupled plasma spectrometer. We found that the introduction of $Al_2O_3$ inter-layer improved the dispersion and stability of the NiO catalysts on the supports. Thus, when an $Al_2O_3$ inter-layer with a 80 nm thickness was grown between the FeCrAl alloy foam and the NiO catalysts, it indicated improved dispersion and stability of the NiO catalysts compared to the other samples. The performance improvement can be explained by optimum thickness of $Al_2O_3$ inter-layer resulting from the role of a passivation layer.

수소제조를 위한 다공성 FeCrAl 금속 합금 Foam의 NiO 촉매 담지 및 미세구조 분석

이유진,안건형,박만호,이창우,최상현,정주용,조성종,이근재,안효진,Lee, Yu-Jin,An, Geon-Hyoung,Park, Man-Ho,Lee, Chang-Woo,Choi, Sang-Hyun,Jung, Ju-Yong,Jo, Sung-Jong,Lee, Kun-Jae,Ahn, Hyo-Jin 한국재료학회 2014 한국재료학회지 Vol.24 No.8

NiO catalysts were successfully coated onto FeCrAl metal alloy foam as a catalyst support via a dip-coating method. To demonstrate the optimum amount of NiO catalyst on the FeCrAl metal alloy foam, the molar concentration of the Ni precursor in a coating solution was controlled, with five different amounts of 0.4 M, 0.6 M, 0.8 M, 1.0 M, and 1.2 M for a dip-coating process. The structural, morphological, and chemical bonding properties of the NiO-catalyst-coated FeCrAl metal alloy foam samples were assessed by means of field-emission scanning electron microscopy(FESEM), scanning electron microscopy-energy dispersive spectroscopy(SEM-EDS), X-ray diffraction(XRD), and X-ray photoelectron spectroscopy(XPS). In particular, when the FeCrAl metal alloy foam samples were coated using a coating solution with a 0.8 M Ni precursor, well-dispersed NiO catalysts on the FeCrAl metal alloy foam compared to the other samples were confirmed. Also, the XPS results exhibited the chemical bonding states of the NiO phases and the FeCrAl metal alloy foam. The results showed that a dip-coating method is one of best ways to coat well-dispersed NiO catalysts onto FeCrAl metal alloy foam.

Synergy between oxides of Ni and Ca for selective catalytic lactic acid synthesis from glycerol in a single step process

Ahmad Zuhairi Abdullah,Muhammad Hazim Yaacob,Nor Irwin Basir 한국공업화학회 2020 Journal of Industrial and Engineering Chemistry Vol.85 No.-

Single-step selective catalytic dehydrogenation of glycerol to lactic acid requires a catalyst with strongdehydrogenation and hydration capabilities. A multi-component catalyst consisting of an alkaline earthmetal and assisted by a transition metal is deemed essential to achieve yield lactic acid in this multi-stepreaction. A series of NiO/CaO catalysts with different Ni/Ca ratios were synthesized via a co-precipitationmethod and tested for their catalytic activity. The physicochemical properties of the catalysts werestudied through TGA, SEM, N2-adsorption, CO2-TPD and XRD analyses. The NiO particles were relativelysmaller than those of CaO to enable their deposition on the surface of the latter. High amounts of basicsites of more than 4.84 mmol/gcat were detected on the NiO/CaO catalysts. The lactic acid yield wasstrongly influenced by the molar ratio of the NiO/CaO catalysts due to their improved dehydrogenationand hydration capabilities. The synergy between NiO with CaO in the catalyst was also elucidated. The0.43NiO/CaO catalyst exhibited desirable activity with 41.4% lactic acid yield at 89.3% glycerol conversion. A catalyst loading of 15 wt. %, a reaction temperature of 290 C and 1.5 h of reaction time were needed toachieve this conversion. Thus, the combination of NiO/CaO resulted in the synergy towards achievingbetter lactic acid yield in this selective conversion to lactic acid. However, accurate control of the reactionwas critical as the intermediates and lactic acid were highly reactive to participate in other side-reactions.

Water-gas shift coupling with methanation over MO_x modified nanorod-NiO/γ-Al_2O_3 catalysts

Shengli Ma,Yizhuo Han,Yisheng Tan 한국공업화학회 2011 Journal of Industrial and Engineering Chemistry Vol.17 No.4

Water-gas shift coupling with methanation was carried out over metal oxide modified nanorod-NiO/γ-Al_2O_3 catalysts prepared by grind-mixing method in a continuous flow type fixed-bed reactor. The effects of promoter type, Co_3O_4 content, and reaction pressure were investigated. From the experimental results, Co_3O_4 modified nanorod-NiO/g-Al_2O_3 catalyst exhibited better activity than NiO–CuO/g-Al_2O_3and NiO–Fe_2O_3/g-Al_2O_3 with molar ratio of CO/H_2/H_2O = 3:1:1 at 593 K and atmospheric pressure. The addition of 10 wt%Co_3O_4 to nanorod-NiO/γ-Al_2O_3 catalyst was optimum. The CO conversion of 50 wt%NiO–10 wt%Co_3O_4/γ-Al_2O_3 catalyst was 7.8% and the CH_4 selectivity reached 83.2%. The NiO–MO_x/γ-Al_2O_3 catalysts were analyzed by X-ray diffraction, temperature programmed reduction and thermogravimetry techniques.

The effect of NiO on the performance of automotive catalysts: Evaluating H2S emission

김하나,이경민,이동철,김상우,차문순,여권구 한국공업화학회 2015 한국공업화학회 연구논문 초록집 Vol.2015 No.0

H2S emission performance of automotive catalyst is one of significant role of air purification catalytic system. NiO could reduce H2S emission by revisable trapping reaction. But, forming alloys with NiO and raw material which are active component in catalyst could bring serious purification performance drop. Hence, demand of optimized level of NiO amount on catalyst increased to establish efficient designing of catalyst. Different amount of NiO contents were induced to automotive catalysts. Various NiO induced automotive catalysts were characterized using comparison of Synthetic Gas bench test and Engine bench test, respectively. The influence of NiO content in automotive catalyst on the emission behavior of the engine bench was discussed.

NiO/La₂O₃-ZrO₂/WO₃ Catalyst Prepared by Doping ZrO₂ with La₂O₃ and Modifying with WO₃ for Acid Catalysis

Sohn, Jong-Rack,Choi, Hee-Dong,Shin, Dong-Chul Korean Chemical Society 2006 Bulletin of the Korean Chemical Society Vol.27 No.6

A series of catalysts, $NiO/La_2O_3-ZrO_2/WO_3$, for acid catalysis was prepared by the precipitation and impregnation methods. For the $NiO/La_2O_3-ZrO_2/WO_3$ samples, no diffraction lines of nickel oxide were observed, indicating good dispersion of nickel oxide on the catalyst surface. The catalyst was amorphous to X-ray diffraction up to 300 ${^{\circ}C}$ of calcination temperature, but the tetragonal phase of $ZrO_2$ and monoclinic phase of $WO_3$ by the calcination temperatures from 400 ${^{\circ}C}$ to 700 ${^{\circ}C}$ were observed. The role of $La_2O_3$ in the catalyst was to form a thermally stable solid solution with zirconia and consequently to give high surface area and acidity. The high acid strength and high acidity were responsible for the W=O bond nature of complex formed by the modification of $ZrO_2$ with $WO_3$. For 2-propanol dehydration the catalyst calcined at 400 ${^{\circ}C}$ exhibited the highest catalytic activity, while for cumene dealkylation the catalyst calcined at 600 ${^{\circ}C}$ showed the highest catalytic activity. 25-$NiO/5-La_2O_3-ZrO_2/15-WO_3$ exhibited maximum catalytic activities for two reactions due to the effects of $WO_3$ modifying and $La_2O_3$ doping.

Preparation and Characterization of NiO/CeO₂-ZrO₂/WO₃ Catalyst for Acid Catalysis

Sohn, Jong Rack,Han, Jong Soo 한국공업화학회 2005 Journal of Industrial and Engineering Chemistry Vol.11 No.3

A series of catalysts, NiO/CeO₂-ZrO₂/WO₃, for acid catalysis was prepared by precipitation and impregnation methods. The characterization of the prepared catalysts was performed by using X-ray diffraction (XRD). X-ray photoelectron spectroscopy (XPS), Fourier transform infrared (FTIR) spectroscopy, differential scanning calorimetry (DSC), and surface area measurements. For the NiO/CeO₂-ZrO₂/WO₃ samples, no diffraction lines of nickel oxide were observed up to 40 wt%, indicating good dispersion of nickel oxide on the catalyst surface. The hexagonal and monoclinic phases of WO₃ were observed when using calcination temperatures up to 500℃. whereas the hexagonal phase of WO₃ was transformed completely into a monoclinic phase of WO₃ at 600℃ and above. The role of CeO, in the catalyst was to form a thermally stable solid solution with zirconia and, consequently, to give high surface area and acidity. The catalytic activities for 2-propanol dehydration and cumene dealkylation correlated with the acidity of the catalysts measured by the ammonia chemisorption method. 20~25- NiO/5-CeO₂-ZrO₂/15-WO₃, containing 20~25 wt% NiO, 15 wt% WO₃, and 5 ㏖% CeO₂and calcined at 400℃, exhibited the maximum catalytic activity because of the effects of WO₃ modifying and CeO₂doping.

Effect of Dispersed MoO3 Amount on Catalytic Activity of NiO-ZrO2 Modified with MoO3 for Acid Catalysis

Jong Rack Sohn*,Sung Gyu Lee,Dong Cheol Shin 대한화학회 2006 Bulletin of the Korean Chemical Society Vol.27 No.10

NiO supported on zirconia modified with MoO3 for acid catalysis was prepared by drying powdered Ni(OH)2-Zr(OH)4 with ammonium heptamolybdate aqueous solution, followed by calcining in air at high temperature. The characterization of prepared catalysts was performed using FTIR, Raman, XRD, and DSC. MoO3 equal to or less than 15 wt% was dispersed on the surface of catalyst as two-dimensional polymolybdate or monomolybdate, while for MoO3 above 15 wt%, crystalline orthorhombic phase of MoO3 was formed, showing that the critical dispersion capacity of MoO3 on the surface of catalyst is 0.18 g/g NiO-ZrO2 on the basis of XRD analysis. Acidity and catalytic activities for acid catalysis increased with the amount of dispersed MoO3. The high acid strength and acidity was responsible for the Mo=O bond nature of the complex formed by the interaction between MoO3 and ZrO2. The catalytic activity for acid catalysis was correlated with the acidity of the catalysts measured by the ammonia chemisorption method.

Effect of Cerium loading on Stability of Ni-bimetallic/ZrO₂ Mixed Oxide Catalysts for CO Methanation to Produce Natural Gas

( Annabathini Geetha Bhavani ),( Hyunki Youn ) 한국화학공학회 2018 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.56 No.2

All the Ni-Co-Ce-ZrO₂ mixed oxides are prepared by co-precipitations methods. Methanation of CO and H₂ reaction is screened tested over different fractions of cerium (2, 4, 7 and 12 wt.%) over Ni-Co/ZrO₂ bimetallic catalysts are investigated. The mixed oxides are characterized by XRD, CO-Chemisorption, TGA and screened methanation of CO and H2 at 360 °C for 3000 min on stream at typical ratio CO:H₂=1:1. In Ni-Co/CeZrO₂ series 2 wt.% Ce loading catalyst shows most promising catalyst for CH₄ selectivity than CO₂, which directs more stability with less coke formation. The high activity is attributed to the better bimetallic synergy and the well-developed crystalline phases of NiO, ZrO₂ and Ce-ZrO₂. Other bimetallic mixed oxides NCoZ, NCoC^4-12Z has faster deactivation with low methanation activity. Finally, 2 wt.% Ce loading catalyst was found to be optimal coke resistant catalyst.

Effect of La2O3 promoter on NiO/Al2O3 catalyst in CO methanation

Hongyun Qin,Cuili Guo,Yuanyuan Wu,Juntao Zhang 한국화학공학회 2014 Korean Journal of Chemical Engineering Vol.31 No.7

A series of NiO/Al2O3 catalysts promoted by different La2O3 contents were prepared by impregnation method. The physicochemical properties of NiO-La2O3/Al2O3 were characterized by N2 adsorption-desorption, X-ray diffraction(XRD), H2 temperature programmed reduction (H2-TPR) and H2 chemisorption. The effect of La2O3 on the activityof NiO/Al2O3 for CO methanation was investigated in a fixed bed reactor. A lifetime test, as well as thermogravimetric(TG) analysis, was performed to investigate the stability performance and anti-carbon deposition of catalysts. Theresults showed that the addition of La2O3 can restrain the growth of NiO particles, increase the H2 uptake and Ni dispersion,and therefore enhance the activity of catalysts. When the La2O3 content was 3 wt%, a CO conversion of 98%and a selectivity to CH4 of 96% were obtained at 400 oC. Furthermore, the catalyst NiO-La2O3/Al2O3 with 3 wt% La2O3content displayed highly stable performance in long-term tests, especially exhibiting good anti-carbon deposition property.