Phenyl VOCs catalytic combustion on supported CoMn/AC oxide catalyst

Guilin Zhou,Xiaoling He,Sheng Liu,Hongmei Xie,Min Fu 한국공업화학회 2015 Journal of Industrial and Engineering Chemistry Vol.21 No.1

Supported CoMn/AC composite oxide catalysts were prepared by a typical impregnation methodat different calcination temperatures. The prepared CoMn/AC catalysts were characterized, and thecatalytic activity of the prepared supported CoMn/AC oxide catalysts was also investigated by thecatalytic combustion of phenyl volatile organic compounds (VOCs) (benzene, toluene, andethylbenzene). XRD and XPS results indicated that MnCo2O4 and CoMn2O4 were the main crystalphase species in the prepared supported CoMn/AC oxide catalysts. The active components wereobserved to be highly dispersed and had small crystal sizes. The toluene catalytic combustion resultsdemonstrated that the CAT350 catalyst had higher toluene catalytic combustion activity than theCTA250, CAT300, and CAT400 catalysts. The toluene catalytic combustion conversion of the CAT350catalyst exceeded 93.5% at 235 8C, with a decreased toluene concentration in air of less than 130 ppm at250 8C. The order of toluene catalytic activity of the supported CoMn/AC oxide catalystswas as follows:CAT250 < CAT300 CAT400 < CAT350. The catalytic combustion activity and stability of the CAT350catalyst also increased with the increase in reaction temperature. The catalytic activity of the CAT350catalyst was investigated to bring about the complete oxidation of benzene, ethylbenzene, and toluene. The combustibility of phenyl VOCs on the CAT350 catalyst was observed to follow the orderbenzene < ethylbenzene < toluene. Therefore, the differences in the phenyl VOC catalytic combustionperformances of the supported CoMn/AC composite oxide catalysts can be attributed to the differentphysical chemistry properties of the phenyl VOC molecules and the catalyst.

PEMFC 전극촉매 Pt/C와 PtCo/C의 촉매 지지체 열화비교

오소형,한유한,정민철,유동근,박권필,Sohyeong Oh,Yoohan Han,Minchul Chung,Donggeun Yoo,Kwonpil Park 한국화학공학회 2023 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.61 No.3

In PEMFC, PtCo/C alloy catalysts are widely used because of good performance and durability. However, few studies have been reported on the durability of carbon supports of PtCo/C evaluated at high voltages (1.0~1.5 V). In this study, the durability of PtCo/C catalysts and Pt/C catalysts were compared after applying the accelerated degradation protocol of catalyst support. After repeating the 1.0↔1.5V voltage change cycles, the mass activity, electrochemical surface area (ECSA), electric double layer capacitance (DLC), Pt dissolution and the particle growth were analyzed. After 2,000 cycles of voltage change, the current density per catalyst mass at 0.9V decreased by more than 1.5 times compared to the Pt/C catalyst. This result was because the degradation rate of the carbon support of the PtCo/C catalyst was higher than that of the Pt/C catalyst. The Pt/C catalyst showed more than 1.5 times higher ECSA reduction than the PtCo/C catalyst, but the corrosion of the carbon support of the Pt/C catalyst was small, resulting in a small decrease in I-V performance. In order to improve the high voltage durability of the PtCo/C catalyst, it was shown that improving the durability of the carbon support is essential.

담지 금속 촉매를 이용한 메탄의 고급 탄화수소로의 전화반응

정헌,우진제,정성일 한국화학공학회 2002 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.40 No.3

담지 금속 촉매를 이용하여 메탄올 2단계 반응에 의해 C_2 이상의 탄화수소로 전화시키는 방법을 연구하였다. 1단계로 메탄올 금속 촉매와 접촉시켜 금속-탄소화합물 및 수소를 만들고, 2단계로 금속-탄소화합물을 수소와 반응시켜 C_2 이상의 탄화수소를 얻었다. 반응은 알루미나에 루세늄 혹은 백금을 담지시킨 촉매층을 채운 석영반응기에서 진행되었고 질량분석기 및 GC를 이용하여 반응물을 분석하였다. 수소화분해 반응 활성이 너무 큰 촉매는 수소화반응 단계에서 메탄을 주로 생산하여 C_2 이상의 탄화수소 수율이 낮고, 수소화분해 반응 활성이 너무 작은 촉매는 탄소화합물의 생성이 어려울 뿐 아니라 생성 속도도 낮았다. 따라서 적당한 수소화분해 반응 활성이 2단계 반응에 의한 메탄전화 반응 촉매의 필수 조건임을 추정할 수 있었다. 담지 금속은 루세늄에 비해 백금이, 백금 담지시 담지량은 0.5%보다는 5%가 적당한 수소화분해 반응 활성을 소유함을 알 수 있었다. 메탄흡착의 최적온도는 250℃ 부근이었다. 본 연구에서 사용된 귀금속 촉매들은 메탄으로부터 수소를 직접 제조하는 촉매 분해기술에도 사용 가능성이 있음을 확인하였다. Methane could be converted to higher hydrocarbons by the two-step reaction using supported metal catalysts. At the first stage methane contacted with metal surface to produce carbonaceous species and hydrogen. Carbonaceous species then reacted with hydrogen to produce higher hydrocarbons at the second stage. Experiments were carried out with alumina-supported ruthenium or platinum catalysts using a quartz tubular reactor. The reaction mixtures were analyzed with a mass spectrometer and a gas chromatograph. The catalyst with too high hydrogenolysis activity produced mostly methane in the second-stage hydrogenation reaction, resulting in the low selectivity toward higher hydrocarbons. When the catalytic activity for the hydrogenolysis reaction was too low, both the selectivity of higher hydrocarbons and the reaction rate were low. Thus, it was concluded that the metal catalyst should have the moderate catalytic activity toward the hydrogenolysis reaction for the maximum conversion of methane to higher hydrocarbons. Supported platinum catalysts exhibited the lower hydrogenolysis activity than the supported ruthenium catalyst, producing larger amounts of higher hydrocarbons. Among supported platinum catalysts, the 5% platinum supported on alumina catalyst, having the moderate hydrogenolysis activity, was superior to the 0.5% Pt supported catalyst. The optimum temperature for the adsorption of methane on metal surface was about 250℃. The noble metal catalysts tested in this work can also be applied to the process of producing hydrogen by direct decomposion of methane.

활성탄 담지 Co-B/C, Co-P-B/C 촉매를 이용한 NaBH₄ 가수분해 반응

오소형 ( Sohyeong Oh ),김유겸 ( Youkyum Kim ),배효준 ( Hyojune Bae ),김동호 ( Dongho Kim ),변영환 ( Younghwan Byun ),안호근 ( Ho-geun Ahn ),박권필 ( Kwon-pil Park ) 한국화학공학회 2018 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.56 No.5

휴대용 고분자전해질 연료전지의 수소발생용으로써 NaBH4는 많은 장점을 갖고 있다. 본 연구에서는 활성탄 담지 Co-B/C, Co-P-B/C 촉매의 NaBH₄ 가수분해 특성에 대해 연구하였다. 촉매의 BET 표면적, 수소 수율, NaBH₄ 농도 영향, 촉매 내구성 등을 실험하였다. 활성탄에 담지시킴으로써 BET 면적이 비담지 촉매에 비해 2~3배 증가해 500 m²/g 이상이 되었다. 활성탄 담지 촉매의 수소발생이 비담지 촉매보다 더 안정적이었다. 20 wt% NaBH₄에서 활성화 에너지가 59.4 kJ/mol로 Co-P-B/FeCrAlloy 촉매 보다 14% 낮았다. 활성탄 담지 촉매가 비담지 촉매에 비해 촉매 손실이 1/3~1/2로 감소해 활성탄에 촉매를 담지시킴으로써 내구성을 향상시킬 수 있었다. Sodium borohydride, NaBH₄, shows a number of advantages as hydrogen source for portable proton exchange membrane fuel cells (PEMFCs). Properties of NaBH4 hydrolysis reaction using activated carbon supported Co-B/C, Co-P-B/C catalyst were studied. BET surface area of catalyst, yield of hydrogen, effect of NaBH₄ concentration and durability of catalyst were measured. The BET surface area of carbon supported catalyst was over 500 m²/g and this value was 2~3 times higher than that of unsupported catalyst. Hydrogen generation of activated carbon supported catalyst was more stable than that of unsupported catalyst. The activation energy of Co-P-B/C catalyst was 59.4 kJ/mol in 20 wt% NaBH₄ and 14% lower than that of Co-P-B/FeCrAlloy catalyst. Catalyst loss on activated carbon supported catalyst was reduced to about 1/3~1/2 compared with unsupported catalyst, therefore durability was improved by supporting catalyst on activated carbon.

Nitrogen-doped carbon nanotube–graphene hybrid stabilizes M_xN (M = Fe, Co) nanoparticles for efficient oxygen reduction reaction

Noh, Woo Yeong,Lee, Jin Ho,Lee, Jae Sung Elsevier 2020 Applied Catalysis B Vol.268 No.-

<P><B>Abstract</B></P> <P>A rationally designed carbon nanotube–graphene (CNT–GR) hybrid support stabilizes selectively the small, nitrogen-rich phase of iron nitride nanoparticles and incorporates effectively nitrogen species into the carbon lattices to yield cost-effective and high-performance platinum group metal (PGM)-free catalysts for the oxygen reduction reaction (ORR). This catalyst–support synergistic effect leads to superior ORR performance with a half-wave potential of 0.89 V <I>vs.</I> the reversible hydrogen electrode and superior durability against carbon corrosion and metal dissolution, compared to the independent use of CNTs and graphene as supports as well as Pt/C catalysts in alkaline media. This hybrid support is also applicable to cobalt nitride catalysts with the similar promotional effects. Therefore, our work explicitly reveals critical new roles of the CNT–GR hybrid material as an efficient support for developing strongly coupled and highly dispersed catalyst/support composites that could open up new avenues for use in a wide range of electrochemical and catalytic applications.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Carbon nanotube–graphene hybrid support is rationally designed. </LI> <LI> The support selectively yields small, nitrogen-rich iron nitride nanoparticles. </LI> <LI> Oxygen reduction reaction performance is superior due to catalyst–support synergy. </LI> <LI> This hybrid support is applicable to cobalt nitride catalysts. </LI> <LI> The hybrid support will aid in designing high-performance platinum-free catalysts. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>A rationally designed CNT–GR hybrid support stabilizes selectively the small, nitrogen-rich phase of iron nitride nanoparticles and effectively incorporates nitrogen species into the carbon lattices to yield cost-effective and high-performance platinum group metal (PGM)-free catalysts for ORR.</P> <P>[DISPLAY OMISSION]</P>

Effect of support materials and Ni loading on catalytic performance for carbon dioxide reforming of coke oven gas

Kim, Hak-Min,Kim, Beom-Jun,Jang, Won-Jun,Shim, Jae-Oh,Jeon, Kyung-Won,Na, Hyun-Suk,Lee, Yeol-Lim,Jeon, Byong-Hun,Roh, Hyun-Seog Elsevier 2019 International journal of hydrogen energy Vol.44 No.16

<P><B>Abstract</B></P> <P>To investigate the effect of support materials on catalytic performance in carbon dioxide reforming of coke oven gas, Ni-based catalysts supported on various metal oxides with various properties are prepared and evaluated. The support material affects the important properties related to the catalytic performance such as surface area, Ni dispersion, basicity, oxygen storage capacity, and interaction between Ni and support. Among the various catalysts on different metal oxides, Ni/MgOAl<SUB>2</SUB>O<SUB>3</SUB> catalyst exhibits the highest CH<SUB>4</SUB> conversion due to its high Ni dispersion, large surface area, and strong basicity. Hence, the Ni loading in the Ni/MgOAl<SUB>2</SUB>O<SUB>3</SUB> catalyst is optimized. Ni loading performs the important roles to determine the Ni dispersion, the amount of Ni active sites, and basicity. 15 wt% Ni/MgOAl<SUB>2</SUB>O<SUB>3</SUB> catalyst shows the highest catalytic activity even at a high gas hourly space velocity (GHSV) of 1,500,000 h<SUP>−1</SUP>, owing to the large amount of Ni active sites which related to Ni loading, Ni dispersion, and reduction degree. To confirm the stability of the 15 wt% Ni/MgOAl<SUB>2</SUB>O<SUB>3</SUB> catalyst, catalytic reaction has been carried out for 50 h and noticeable catalytic deactivation is not observed for 50 h.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Effect of support material on catalyst for CO<SUB>2</SUB> reforming of COG is investigated. </LI> <LI> Support materials affect Ni dispersion, basicity, and oxygen storage capacity. </LI> <LI> Among the supported catalysts, Ni/MgOAl<SUB>2</SUB>O<SUB>3</SUB> shows the highest performance. </LI> <LI> Ni loading affects Ni dispersion, the amount of Ni active sites and basicity. </LI> <LI> 15 wt% Ni/MgOAl<SUB>2</SUB>O<SUB>3</SUB> exhibits the highest activity and stability. </LI> </UL> </P>

The Effect of Sc Promoter on the Performance of Co/TiO2–P25 Catalyst in Dry Reforming of Methane

Ahmed Sadeq Al-Fatesh,Muhammad Awais Naeem,Anis Hamza Fakeeha,Ahmed Elhag Abasaeed 대한화학회 2015 Bulletin of the Korean Chemical Society Vol.36 No.8

In the present work, the effect of scandium (Sc) promoter on the performance of Co/TiO2–P25 catalyst in dry reforming of methane has been investigated. The catalysts were prepared by the incipient wet impregnation technique. For each catalyst, the Co loading was fixed at 5 wt %, while the Sc loading was varied from 0.0 to 2.0 wt %. The experiments were carried out at atmospheric pressure in a micro tubular reactor at a temperature of 700 °C. For better understanding and comparison, the catalysts were characterized by various techniques such as Brunauer–Emmett–Teller (BET), X-ray diffraction (XRD), H2-temperature-programmed reduction (TPR), CO2-temperature-programmed desorption (TPD), and thermogravimetric analyses (TGA). The results revealed that the promotion of Co/TiO2–P25 catalyst with Sc has a significant impact on its catalytic performance and the amount of carbon deposition. The doping of Co/TiO2–P25 catalyst with Sc improves the basicity and enhances the metal support interaction in the catalyst. At higher Sc loading, Co metal oxidation became substantial that triggered severe catalyst deactivation. Amongst all Sc-promoted catalysts, 0.75 wt % Sc-promoted catalyst exhibited the highest CH4 and CO2 activity with minimum deactivation.

Effect of support on hydrogen production by auto-thermal reforming of ethanol over supported nickel catalysts

In Kyu Song,Min Hye Youn,서정길,Kyung Min Cho,정지철,Heesoo Kim,Kyung Won La,Dong Ryul Park,Sunyoung Park,Sang Hee Lee 한국화학공학회 2008 Korean Journal of Chemical Engineering Vol.25 No.2

Nickel catalysts supported on various supports such as ZnO, MgO, ZrO2, TiO2, and Al2O3 were prepared by an impregnation method to investigate the effect of support on catalytic performance in hydrogen production by auto-thermal reforming of ethanol. Among the supported catalysts, the Ni/ZrO2 and Ni/TiO2 catalysts showed better catalytic performance than the other catalysts. The electronic structure of nickel species supported on ZrO2 and TiO2 was favorably modified for the reaction, and thus, the reducibility of nickel species supported on ZrO2 and TiO2 was increased due to the weak interaction between nickel and support. On the other hand, the Ni/MgO and Ni/ZnO catalysts exhibited poor catalytic performance in the auto-thermal reforming of ethanol due to the formation of a solid solution phase.

Stabilization of Pt at the inner wall of hollow spherical SiO₂ generated from Pt/hollow spherical SiC for sulfuric acid decomposition

Khan, Hassnain Abbas,Natarajan, Prakash,Jung, Kwang-Deog Elsevier 2018 Applied catalysis. B, Environmental Vol.231 No.-

<P><B>Abstract</B></P> <P>Catalysts for sulfuric acid (SA) decomposition, one of three reactions in Sulfur-Iodine (SI) cycle to produce hydrogen, should be active and stable up to 800–900 °C. Here, a SiC hollow sphere supported Pt catalyst (1 wt% Pt/hSiC) is prepared, and its catalytic activity and stability are monitored in SA decomposition at 850 °C. The initial SA conversion with the Pt/hSiC catalyst is ca. 80% at 850 °C and a GHSV of 76,000 mL/g<SUB>cat</SUB>/h. For comparison, a core-shell SiO<SUB>2</SUB> supported Pt catalyst (1 wt% Pt/SiO<SUB>2</SUB>@mSiO<SUB>2</SUB>) is prepared and tested for the reaction. The core-shell SiO<SUB>2</SUB> support has the structure of a dense core and a mesoporous shell. The initial SA conversion with the Pt/SiO<SUB>2</SUB>@mSiO<SUB>2</SUB> catalyst is ca. 54% at 850 °C and a GHSV of 76,000 mL/g<SUB>cat</SUB>/h. The Pt/hSiC catalyst is transformed to the SiO<SUB>2</SUB> hollow sphere supported Pt catalyst (Pt/hSiO<SUB>2</SUB>) within 6 h reaction. CO chemisorption and TEM analysis exhibit that Pt particles on the pristine and spent catalysts, pretreated at 850 °C, are encapsulated by SiC or SiO<SUB>2</SUB> on the surfaces of SiC and SiO<SUB>2</SUB> supports. When the encapsulated Pt particles are in contact with sulfuric acid vapor, the Pt particles are exposed to the reactants by the removal of SiO<SUB>2</SUB> encapsulating Pt during the reaction. Pt particles at the outer wall of the pristine hSiC are partly lost via PtOx evaporation, while Pt particles at the inner wall of the hollow sphere supports are stabilized without the severe Pt loss and Pt sintering. In contrast, the Pt particles on SiO<SUB>2</SUB>@mSiO<SUB>2</SUB> with the dense SiO<SUB>2</SUB> core are severely lost via PtOx evaporation during the reaction resulting in severe Pt sintering. The high stability of Pt particles at the inner wall of the hollow support is attributed to the Pt encapsulation and Pt anchoring of the small Pt particles at the inner walls and the diffusion barrier role of the shell for the migration of Pt at the inner wall to the outer wall.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Pt is encapsulated by SiO<SUB>2</SUB> and exposed to reactants with sulfuric acid at 850 °C. </LI> <LI> Pt loss and Pt sintering at inner walls of hollow sphere are prevented. </LI> <LI> Pt at outer walls of hollow sphere is severely lost and sintered. </LI> <LI> The catalyst design of Pt@hollow sphere is promising for SA decomposition. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P> <B>Hollow SiC supported Platinum catalyst:</B> Pt nano particles encapsulated into hollow sphere SiC(Pt/hSiC) have been prepared by polyol method. Facile synthesis not only confined the Pt into pores but partially embedded into the inner surface of the hSiC shell, which could effectively prevent the Pt NPs from agglomeration or leaching during the reaction, which resulted in high stability till 50 h.</P> <P>[DISPLAY OMISSION]</P>

Cu/ZnO/AlOOH catalyst for methanol synthesis through CO2 hydrogenation

최은경,송경호,안소라,이관영,윤민혜,박기태,정순관,김학주 한국화학공학회 2018 Korean Journal of Chemical Engineering Vol.35 No.1

Catalytic conversion of CO2 to methanol is gaining attention as a promising route to using carbon dioxide as a new carbon feedstock. AlOOH supported copper-based methanol synthesis catalyst was investigated for direct hydrogenation of CO2 to methanol. The bare AlOOH catalyst support was found to have increased adsorption capacity of CO2 compared to conventional Al2O3 support by CO2 temperature-programmed desorption (TPD) and FT-IR analysis. The catalytic activity measurement was carried out in a fixed bed reactor at 523 K, 30 atm and GHSV 6,000 hr−1 with the feed gas of CO2/H2 ratio of 1/3. The surface basicity of the AlOOH supported Cu-based catalysts increased linearly according to the amount of AlOOH. The optimum catalyst composition was found to be Cu : Zn : Al=40 : 30 : 30 at%. A decrease of methanol productivity was observed by further increasing the amount of AlOOH due to the limitation of hydrogenation rate on Cu sites. The AlOOH supported catalyst with optimum catalyst compositions was slightly more active than the conventional Al2O3 supported Cu-based catalyst.