In this work,the steam reforming of acetic acid was catalyzed by Ni-based catalysts supported on ceria-zirconia of different morphological structures(nanopolyhedra,nanorods,and nanocubes).The altered shapes led to the...In this work,the steam reforming of acetic acid was catalyzed by Ni-based catalysts supported on ceria-zirconia of different morphological structures(nanopolyhedra,nanorods,and nanocubes).The altered shapes led to the variation in catalyst properties,such as the exposed planes,ease of Ni reduction/oxidation,and carbon removal,which affected its catalytic performance.Additionally,it was found that the exposed planes present in cubic{100}and rod structures({100}and{110})enhanced the formation of Ni^(0) and subsequently promoted the reforming reaction.Moreover,oxygen vacancies and mobility properties of{100}and{110}exposed planes can promote the oxidation reaction of carbon,resulting in a stable catalyst for the reforming of acetic acid.The results also showed that the type of depositing carbons was influenced by the support morphology.All the catalysts showed a100% acetic acid conversion with the 15Ni/NC-Ce Zr(cubic structure)catalyst exhibited the highest hydrogen yield.展开更多
Methane partial oxidation （MPO） is considered as an alternative method to produce hydrogen because it is an exothermic reaction to afford a suitable H2/CO ratio of 2. However, carbon deposition on a catalyst is obse...Methane partial oxidation （MPO） is considered as an alternative method to produce hydrogen because it is an exothermic reaction to afford a suitable H2/CO ratio of 2. However, carbon deposition on a catalyst is observed as a major cause of catalyst deactivation in MPO. In order to find suitable catalysts that prevent the carbon deposition, NiO-MgO/Ce0.75Zr0.2502 （CZO） supported catalysts were prepared via the co-impregnation （C） and sequential incipient wetness impregnation （S） methods. The amount of Ni loading was fixed at 15 wt-% whereas the amount of MgO loading was varied from 5 to 15 wt-%. The results revealed that the addition of MgO shifted the light-off temperatures to higher temperatures. This is because the Ni surface was partially covered with MgO, and the strong interaction between NiO and NiMgO2 over CZO support led to the difficulty in reducing NiO to active Ni~ and thus less catalytic activity. However, among the catalysts tested, the 15Ni5Mg/CZO （S） catalyst exhibited the best catalytic stability for MPO after 18 h on stream at 750℃. Moreover, this catalyst had a better resistance to carbon deposition due to its high metallic Ni dispersion at high temperature.展开更多
基金financial support from the Petroleum and Petrochemical College,Chulalongkorn University and the Center of Excellence on Petrochemical and Materials Technologythe Ratchadapisek Somphot Fund for Postdoctoral Fellowship,Chulalongkorn University。
文摘In this work,the steam reforming of acetic acid was catalyzed by Ni-based catalysts supported on ceria-zirconia of different morphological structures(nanopolyhedra,nanorods,and nanocubes).The altered shapes led to the variation in catalyst properties,such as the exposed planes,ease of Ni reduction/oxidation,and carbon removal,which affected its catalytic performance.Additionally,it was found that the exposed planes present in cubic{100}and rod structures({100}and{110})enhanced the formation of Ni^(0) and subsequently promoted the reforming reaction.Moreover,oxygen vacancies and mobility properties of{100}and{110}exposed planes can promote the oxidation reaction of carbon,resulting in a stable catalyst for the reforming of acetic acid.The results also showed that the type of depositing carbons was influenced by the support morphology.All the catalysts showed a100% acetic acid conversion with the 15Ni/NC-Ce Zr(cubic structure)catalyst exhibited the highest hydrogen yield.
文摘Methane partial oxidation （MPO） is considered as an alternative method to produce hydrogen because it is an exothermic reaction to afford a suitable H2/CO ratio of 2. However, carbon deposition on a catalyst is observed as a major cause of catalyst deactivation in MPO. In order to find suitable catalysts that prevent the carbon deposition, NiO-MgO/Ce0.75Zr0.2502 （CZO） supported catalysts were prepared via the co-impregnation （C） and sequential incipient wetness impregnation （S） methods. The amount of Ni loading was fixed at 15 wt-% whereas the amount of MgO loading was varied from 5 to 15 wt-%. The results revealed that the addition of MgO shifted the light-off temperatures to higher temperatures. This is because the Ni surface was partially covered with MgO, and the strong interaction between NiO and NiMgO2 over CZO support led to the difficulty in reducing NiO to active Ni~ and thus less catalytic activity. However, among the catalysts tested, the 15Ni5Mg/CZO （S） catalyst exhibited the best catalytic stability for MPO after 18 h on stream at 750℃. Moreover, this catalyst had a better resistance to carbon deposition due to its high metallic Ni dispersion at high temperature.
