CATALYSIS LETTERS
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2019
·Vol. 149
·期 4
·1007-1016
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IF 2.372
Liu Pengcheng,Niu Ruyue,Li Wei,Wang Shuang,Li Jinping
Three Ru/CeO 2 catalysts with different morphologies of CeO 2 (cube spheres, microspheres and nano rods) were used to evaluate the support-morphology-dependent ammonia synthesis activity. Catalytic experiments show that the Ru/CeO 2 –CS catalyst has higher catalytic activity (27,000 µmol g −1 h −1 ) than Ru/CeO 2 –MS (21,000 µmol g −1 h −1 ) and Ru/CeO 2 –NR (15,000 µmol g −1 h −1 ) under the reaction conditions of 450 °C, 3 MPa, H 2 /N 2 = 3:1 (60 mL min −1 ). The transmission electron microscopy analysis showed that the dispersion of active metal Ru is affected by the morphology of CeO 2 . Brunauer–Emmett–Teller indicates that the 3–5 nm the pore size of CeO 2 supports contributes to the active metal Ru enters the pores of the CeO 2 support, which improves the dispersion of Ru and prevents the sintering and agglomeration of Ru in some extent. TPR studies shown that the reduction of ruthenium oxide is influenced by the morphology of CeO 2 . XPS and CO 2 -TPD demonstrated that the Ru/CeO 2 –CS catalyst exhibited higher surface oxygen vacancies, higher basic site density and lower Ru binding energy, indicating that Ru nanoparticles in Ru/CeO 2 –CS is more electron-rich and are more capable of back-donating electrons to adsorbed N 2 and subsequently activate N 2 . Our results indicate that the morphology effect of the CeO 2 supports on the Ru/CeO 2 catalyst is related to the pore size distribution and the surface oxygen vacancies of the CeO 2 supports, ratio of Ru n+ , basic site density. Graphical Abstract
The CeO 2 –CS (cube spheres) morphology facilitated the dispersion of the active metal Ru and the 3 nm the pore size of CeO 2 –CS contributed to the Ru enters the pores of the support. And the Ru/CeO 2 –CS catalyst exhibited higher surface oxygen vacancies and lower Ru binding energy, which enhanced the adsorption of hydrogen and nitrogen species and thus weakened the N≡N bond.
研究领域:
催化化学
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材料科学
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DOI
高影响因子
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
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2023
·
IF 7.2
Long Xie,Bin Hu,Riyang Shu,Zhipeng Tian,Ying Chen,Chao Wang
Methanol reforming has been a popular pathway to produce hydrogen due to the high hydrogen storage density of methanol. CeO 2 as the support is widely used for catalytic methanol reforming, but the effect of CeO 2 morphology on the reaction mechanism has not been revealed out. In this study, the catalytic performances of Ru/CeO 2 with different CeO 2 morphology, including rod , cubic and their mixed, were investigated in methanol reforming for the production of hydrogen. By regulating the temperature during hydrothermal preparation, different CeO 2 supports can be achieved. Results showed that Ru/CeO 2 catalyst with rod CeO 2 (Ru/r-CeO 2 ) exhibited a much better catalytic performance than the cubic catalyst (Ru/c-CeO 2 ) and the mixed catalyst (Ru/m-CeO 2 ), with a higher yield of hydrogen and a lower selectivity of CO product. This was mainly due to the large surface area that favored the dispersion of Ru metal site and the interaction between Ru and CeO 2 support that improved the electron transfer to benefit the formation of oxygen vacancy . Therefore, the Ru/r-CeO 2 catalyst possessed abundant oxygen vacancy , which enabled to adsorb the methanol efficiently and trigger the methanol reforming reaction . It also can enhance the adsorption of CO and water and promote the water-gas-shift reaction to increase the yield of hydrogen production .
研究领域:
催化化学
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能源科学
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产品关联
DOI
高影响因子
RENEWABLE ENERGY
·
2024
·
IF 9
Daxin Jiang,Min Lin,Yuhao Yan,Lulu Zhan,Rui Li,Yulong Wu
Catalytic hydrodeoxygenation (HDO) is an effective way to produce high–value products from lignin-derived phenolic compounds. In this work, three different morphologies of Ni/CeO 2 catalysts (amorphous, cubic, and rod-shaped) have been prepared through the conventional wet impregnation method. They can be used for the HDO of guaiacol to prepare cyclohexanol, an important chemical raw material. The influence of different morphologies of CeO 2 on catalytic activity was explored. The research results indicate that Ni/CeO 2 –r catalysts with rod-shaped structures exhibit excellent catalytic properties. As a result, a 100 % conversion rate and 96.9 % cyclohexanol yield were achieved on the Ni/CeO 2 –r catalyst at 240 °C. The catalytic performance of the three catalysts follows this order: Ni/CeO 2 –r (rod-shaped) > Ni/CeO 2 –c (cubic) > Ni/CeO 2 –p (amorphous). The results of Raman and XPS indicate significant differences in the surface oxygen vacancy in catalysts with different morphologies. The Ni/CeO 2 –r catalyst has the highest oxygen vacancy concentration and defect. In addition, Ni/CeO 2 –r also has the largest specific surface area (S BET ) and the highest nickel dispersion, and forms more Ni 0 because of the strong interaction of Ni species and CeO 2 support. Therefore, Ni/CeO 2 –r exhibits the most excellent catalytic performance for the hydrogenation of guaiacol than the other two catalysts. Moreover, the cycling activity test was also investigated over the Ni/CeO 2 –r catalyst. After five cycles, the conversion rate of guaiacol and the yield of cyclohexanol hardly decrease. This work provides vital ideas for the development of higher-activity, higher-stability, and low-cost catalysts for the conversion of lignin-derived phenolic compounds in the future.
研究领域:
催化化学
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材料科学
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能源化学
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产品关联
DOI
高影响因子
CATALYSIS LETTERS
·
2019
·Vol. 149
·期 2
·361-372
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IF 2.372
Liu Yanan,Yang Zhao,Zhang Xinyi,He Yufei,Feng Junting,Li Dianqing
Abstract A series of CeO 2 with the morphology of nanocube (NC), nanopolyhedron (NP) and nanorod (NR) were synthesized by hydrothermal method as substrates to support monometallic Au catalysts. Insight into support morphology-dependent the property of active component and catalytic behavior for the selective hydrogenation of phenylacetylene has been performed. Specifically, nanocube ceria could disperse monometallic Au nanoparticles due to a large amount of low coordinated sites that readily generated the strong interaction for anchoring active metal, whereas the polyhedron and rod-like ceria supported Au nanoparticles possessed large size and wide particle distribution. As expected, well-dispersed and stable Au/CeO 2 nanocube demonstrated 83% of selectivity towards styrene when the conversion of phenylacetylene reached 90%, which was much higher than that of others. Preferable activity was mainly ascribed to small size of Au nanoparticles, which facilitated the adsorption/dissociation of hydrogen considered as the rate-determining step. Enhanced selectivity was due to the electronic effect that caused by strong interaction between Au and cubic CeO 2 , which also contributed to good stability. This work not only provides a facile method for the preparation of highly dispersed and efficient Au/CeO 2 catalysts by modulating the morphology of support, but also offers a novel idea for the fabrication of other highly dispersed supported metal catalysts with enhanced behavior in heterogeneous catalysis. Graphical Abstract
研究领域:
催化化学
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材料科学
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DOI
高影响因子
APPLIED SURFACE SCIENCE
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2019
·
IF 5.155
Xiaoliang Li,Jiangjiang Feng,Michal Perdjon,Rena Oh,Wei Zhao,Xiaoyang Huang,Shusen Liu
Au-Pd bimetallic nanoparticles immobilized on series of CeO 2 supports with different morphologies, e.g. , rod, cube, and polyhedrons were prepared through the deposition-precipitation method with a consequent investigation on their catalytic performances for benzyl alcohol oxidation in the absence of solvent. The experimental results exhibited that the morphology of CeO 2 has a markedly impact on the catalytic performance of Au-Pd/CeO 2 . In which Au-Pd supported on CeO 2 rod could achieve higher benzyl alcohol conversion than that supported on CeO 2 polyhedrons and CeO 2 cube, however, CeO 2 cube supported Au-Pd showed the highest selectivity towards the production of benzaldehyde. ICP-AES, XRD, Raman, N 2 -BET, TEM, HAADF-STEM, and XPS were conducted to characterize the catalysts. The results revealed that the excellent behavior of Au-Pd/CeO 2 -rod in benzyl alcohol oxidation was closely related with the smaller size of CeO 2 particle, the higher concentration of oxygen defects in support and the higher number of Ce 3+ and Pd 2+ species on the catalyst surface. The present study on the morphologies of CeO 2 support in solvent-free benzyl alcohol oxidation would offer a notable approach for the future catalyst design.
研究领域:
材料科学
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催化化学
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DOI
高影响因子
ENERGY & FUELS
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2022
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IF 4.654
Chenglong Wen,Mohong Lu,Mengyang Zhao,Jie Zhu,Mingshi Li,Jian Shang,Yuhua Shan,Chunshan Song
CeO2 with three different morphologies of nanorods (CeO2-r), particles (CeO2-p), and cubes (CeO2-c) was prepared, and the guaiacol hydrodeoxygenation over their corresponding Co-based catalysts was performed at 160–220 °C, 2 MPa, a H2 flow rate of 80 mL/min, and a weight hourly space velocity of 0.7 h–1. Compared with Co/CeO2-p and Co/CeO2-c, Co/CeO2-r has smaller Co particle sizes, a higher Brunauer–Emmett–Teller surface area, and larger amount of Co active centers, oxygen vacancies, and weak acid sites. These better physicochemical properties for Co/CeO2-r provide more Co active sites for guaiacol hydrodeoxygenation, favor the adsorption and activation of guaiacol, and contribute to the cleavage of C–O. Therefore, Co/CeO2-r presents a maximum guaiacol conversion of 97.1% and the highest yield of cyclohexanol of 91.7% among these catalysts. The result shows that the shape structure of CeO2 has an important influence on the guaiacol hydrodeoxygenation performance over its corresponding catalysts.
研究领域:
催化化学
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能源化学
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DOI
高影响因子
FUEL
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2023
·
IF 7.4
Zhongchun Yuan,Tingting Cao,Min Deng,Jun Ma,Shuo Geng,Chunliang Yang,Yuan Ren,Mengqin Yao,Fei Liu,Xiaodan Wang
It is very crucial but still a huge challenge to develop efficient and durable catalysts to promote hydrogen production from formic acid (FA). Herein, three CeO 2 with structurally well-defined different shapes, i.e., sCeO 2 (spheres), rCeO 2 (rod) and oCeO 2 (octahedral), are prepared, and their effect on the crystal faces and oxygen vacancy over the constructed heterostructure catalysts (Pd-CeO 2 /C) have been intensively investigated in the FA dehydrogenation. Pd-sCeO 2 /C outperforms the other catalysts with a turnover frequency (TOF) value of 2691 h −1 and selectivity to hydrogen of 100 % at 30 °C. A synergism between the CeO 2 (1 1 0) facet and more oxygen vacancies is considered to be key to obtaining the high reactivity. Moreover, biomass carbon promotes the dispersion of Pd-CeO 2 heterostructures due to its large specific surface area and causes more defects in the Pd-CeO 2 /C. Combined with in-situ FTIR and density functional theory (DFT), it is speculated that FA is decomposed through formate pathway over the Pd-sCeO 2 /C. This work thus provides a reasonable design and controllable synthesis strategy for the effective application of FA as an available liquid phase hydrogen storage material.
研究领域:
催化
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材料科学
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化学工程
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物理化学
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产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）