Catalysts
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2017
·Vol. 7
·期 1
·21
·
IF 3.082
Yang Han,Bo Wen,Mingyuan Zhu
In this study, we prepared core-shell structured Ni@SiO2catalysts using chemical precipitation and modified Stöber methods. The obtained Ni@SiO2samples exhibited excellent catalysis performances, including high CO conversion of 99.0% and CH4yield of 89.8%. Moreover, Ni@SiO2exhibited excellent catalytic stability during a 100 h lifetime test, which was superior to that of the Ni/SiO2catalyst. The prepared samples were characterized using a series of techniques, and the results indicated that the catalytic performance for syngas methanation reaction of the Ni@SiO2sample was markedly improved owing to its nanoreactor structure. The strong interaction between the Ni core and the SiO2shell effectively restrained the growth of particles, and the deposition of C species.Keywords:syngas methanation;Ni@SiO2;anti-carbon deposition;catalytic stability
研究领域:
化学工程
·
催化材料
✓ 已验证
DOI
高影响因子
CHEMICAL ENGINEERING SCIENCE
·
2022
·
IF 4.889
He Han,Anfeng Zhang,Limin Ren,Xiaowa Nie,Min Liu,Yi Liu,Chuan Shi,Hong Yang,Chunshan Song,Xinwen Guo
Shape-selective alkylation of toluene with methanol is one of the most attractive promising synthetic routes to para -xylene. To date, modified ZSM-5 zeolites are considered to be one of the best candidate catalysts for this reaction. Although the para -selectivity could be tuned to approaching 100% by modification of the zeolite and optimization of reaction conditions, at present, there is still a lack of effective means to inhibit the rapid deactivation of the catalysts due to coke formation. In this work, a coke-resistant (Pt + Ni)/ZSM-5 zeolite with excellent stability for shape-selective alkylation of toluene with methanol to para -xylene is developed. The pore structure and acid properties of the zeolite are effectively tuned to ensure high para -selectivity. Meanwhile, the co-existence of Pt and Ni species in this catalyst plays the critical role in inhibiting coke formation, as the two species concurrently impede the formation of olefins, the main coking precursors, via two distinctive mechanisms.
研究领域:
催化化学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING SCIENCE
·
2023
·
IF 4.7
Kai Shi,Yang Deng,Xia An,Xu Wu,Xianmei Xie
This work focused on optimizing the synergistic effect between CeO 2 and Ni in CeO 2 modified Ni/MgAl 2 O 4 . Six catalysts for ethanol steam reforming (ESR), including NiCeMgAl, CeO 2 /NiMgAl, Ni/CeMgAl, Ni-CeO 2 /MgAl 2 O 4 , Ni/CeO 2 /MgAl 2 O 4 and CeO 2 /Ni/MgAl 2 O 4 , were synthesized by sol–gel and/or impregnation methods, which controlled the introduction order of Ce(NO 3 ) 3 . Ni/CeMgAl showed a satisfactory stability with 90.6 % of ethanol conversion after 100 h test, 66.9 % of H 2 concentration in product, and an excellent anti-coking ability with 0.72 mg c /(g cat ·h). The optimal catalytic performance of Ni/CeMgAl benefits from the unique distribution of components, which provides adequate Ni 0 active sites for C-C bonds scission, maintains a stable particle size of metallic Ni, and suppresses the side reactions and carbonization of intermediates on CeO 2 sites. This work illuminates the important of coordinating the ability of Ni and CeO 2 for ESR and presents a new insight into the design of low-cost and high-performance catalysts in practical applications.
研究领域:
催化化学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2024
·
IF 13.3
Kai Shi,Yin Che,Yang Deng,Xia An,Xianmei Xie,Xu Wu
Bimetallic catalysts with unique geometric and electronic structure exhibit high performance compared to that of monometallic counterparts in the ethanol steam reforming (ESR). Herein, NiCo bimetals supported on CeO 2 doped MgAl 2 O 4 (NiCo/CeMgAl) with different ratio of Ni/Co were prepared for ESR. The synergies between Ni and Co in catalytic activities and ability to anti-coking were focused. The results demonstrate Co atoms trend to segregate toward the surface and are oxidized synchronously, forming the Ni-CoO hybrid surface. The reduced Ni particles are beneficial to maintain a stable catalytic activity for the C-C bonds scission, and the CoO particles formed by segregation and irreversible oxidation of Co 0 are more conducive to activation of H 2 O, the resulting OH promotes the transformation of CH x species, which significantly reduces the selectivity of CH 4 and prevents the formation of filamentous carbon. Controlling Co content and maintaining a stable M/M δ+ are critical to balance the C-C bond scission reaction and the CH 3 * conversion reaction on the NiCo bimetallic catalysts. The optimal catalyst 9Ni1Co/CeMgAl shows the ethanol conversion of 93.9 % at TOS of 100 h, and the average rate of coke formation is 0.50 mg c ·g cat -1 ·h −1 .
研究领域:
化学工程
·
催化
✓ 已验证
产品关联
DOI
高影响因子
FUEL PROCESSING TECHNOLOGY
·
2019
·
IF 4.507
Huiying Wang,Zhenning Yang,Jie Liu,Guozhu Li,Xiangwen Zhang
Coking during endothermic hydrocarbon fuel cracking is a key problem that has to be considered. In this study, anti-coking effect was systematically studied by using water, ethanol and HPW as additives on the coatings of CsOH and BaCeO 3 during RP-3 cracking. The morphology, type and amount of coke deposits on the coatings were characterized by means of scanning electron microscopy (SEM), temperature programmed oxidation (TPO) and quantitative carbonization method, respectively. The results show that either the additive or the catalytic coating can effectively remove the coke deposits on the reaction tube. Remarkably, BaCeO 3 coating is more effective in inhibiting the formation of fiber coke compared with CsOH coating，which is conducive to the cracking reaction. The best anti-coking effect is achieved by using 5 wt% ethanol as additive on the BaCeO 3 /HPW coating, and the inhibiting percentage is 97%. In addition, a possible anti-coking mechanism of carbon-steam gasification through BaCeO 3 /HPW coating and ethanol has been proposed.
研究领域:
化学工程
·
能源科学
✓ 已验证
产品关联
DOI
高影响因子
ENERGY & FUELS
·
2020
·
IF 3.421
Li Zhang,Yue Hu,Weibin Xu,Chuande Huang,Yang Su,Ming Tian,Yanyan Zhu,Huimin Gong,Xiaodong Wang
Iron-based oxides are promising oxygen carriers for chemical looping syngas production from methane; however, facile coke formation over reduced metallic Fe0 largely limits the syngas productivity. This work demonstrates that the introduction of Sn promoters into BaFe1–xSnxO3−δ perovskite oxides significantly restrains coke formation and improves the syngas yield to above 19.2 mmol/g with a H2/CO ratio of 2, which is 2.9-fold in comparison to BaFeO3−δ. Characterization results suggest that Sn cations are well-confined in the perovskite matrix by substitution of Fe. The Fe cations serve as main active sites for C–H bond activation with Sn cations as an oxygen reservoir, which donate the neighboring lattice oxygen to active Fe for selective methane oxidation. Besides, an intimate Fe–Sn interaction induces the formation of the FeSn alloy rather than metallic Fe0 under a reducing atmosphere, which restrains methane pyrolysis and notably improves the coke resistance. When Sn loading (x) increases to above 0.6, all Fe cations can be deeply reduced to the metallic state without coke accumulation and oxygen storage capacity reaches as high as ca. 6.5 mmol/g with nearly 100% syngas selectivity, which breaks the “seesaw” effect between oxygen supply and syngas selectivity for traditional iron-based materials. These results provide meaningful guidance for fabricating prospective oxygen carriers or catalysts with better anti-coke property for the chemical looping process or specific catalytic reactions.
研究领域:
材料科学
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催化化学
✓ 已验证
产品关联
DOI
高影响因子
ENERGY
·
2024
·
IF 9
Yuechi Che,Xiaopeng Jia,Yongjie Hu,Jian Li,Zhi Wang,Beibei Yan,Guanyi Chen
Tar catalytic removal is a key issue in biomass gasification , which is suffering from catalyst coking and sintering. Microwave technology is attractive due to the high activity on polar molecules and ability to lower activation energy . In this study, the Co/C derived from metal-organic frameworks (ZIF-67) was developed as a bifunctional microwave catalyst that can strengthen the interaction between microwave and tar catalytic reforming , and enhance the anti-coking and sintering ability. The effects of the temperature, heating method, tar concentration, and catalyst support on model tar conversion rate were investigated. The operating conditions at 700 °C and tar concentration lower than 20 g/m 3 can reach a promising conversion rate over 90.15 % under microwave irradiation . On the one hand, microwave heating groups performed better in conversion rate and coking compared to conventional heating, due to the active species generated from the microwave plasma . On the other hand, Co/C showed better performance in catalytic activity and sintering stability, due to the highly dispersion of cobalt nanoparticles and the confinement effect of carbon nanotubes on the catalyst surface . These findings proposed a novel approach for efficient biomass tar removal under microwave irradiation, and offered a potential tool to further reveal the mechanism in microwave driven tar steam reforming system.
研究领域:
能源与环境科学
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催化化学
✓ 已验证
产品关联
DOI
高影响因子
Materials
·
2022
·Vol. 15
·期 9
·3044
·
IF 3.748
Yu Shi,Shiwei Wang,Yiming Li,Fan Yang,Hongbo Yu,Yuting Chu,Tong Li,Hongfeng Yin
A series of NiP-x/Al2O3catalysts containing different ratio of metallic nickel to nickel phosphides, prepared by varying Ni/P molar ratio of 4, 3, 2 through a co-impregnation method, were employed to investigate the synergistic effect of metallic nickel-nickel phosphides in dry methane reforming reaction. The Ni/Al2O3catalyst indicates good activity along with severe carbon deposition. The presence of phosphorus increases nickel dispersion as well as the interaction between nickel and alumina support, which results in smaller nickel particles. The co-existence of metallic nickel and nickel phosphides species is confirmed at all the P contained catalysts. Due to the relative stronger CO2dissociation ability, the NiP-x/Al2O3catalysts indicate obvious higher resistance of carbon deposition. Furthermore, because of good balance between CH4dissociation and CO2dissociation, NiP-2/Al2O3catalyst exhibits best resistance of carbon deposition, few carbon depositions were formed after 50 h of dry methane reforming.Keywords:dry methane reforming;nickel catalysts;phosphides;coke-resistance;synergistic effect
研究领域:
催化
·
化学工程
·
材料科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
APPLIED CATALYSIS A-GENERAL
·
2023
·
IF 5.5
Cheng Cang Li,Da Jian Li,Shu Tian Yin,Ze Zhen Wang,Chen Lan Liu,Chun Hui Zhou
Glycerol can be converted to allyl alcohol via deoxydehydration using molybdenum-vanadium, rhenium and iron based catalysts. However, the dehydration causes severe coking at strong acid sites on the surface of catalyst. Molybdenum-vanadium oxide supported on calcium oxide-intercalated montmorillonite (MoV-CaMMT) was prepared by oxalate anion intercalation followed by impregnation. MoV-CaMMT displayed the best catalytic performance of 86.5% glycerol conversion and good stability in 5 h. Correlating the results of XRD, XPS and TG analysis, it can be demonstrated that the addition of CaO in the catalyst preparation is conducive to the crystallization and dispersion of vanadium oxides, and reduces the acid strength, while the presence of a few vanadium dioxide and the stable conversion of V 4+ and V 5+ are the reasons for enhancing coking-resistance of MoV-CaMMT. Additionally, NH 3 -TPD analysis proved the coexistence of weak and strong acid sites in MoVO x , which are conducive to the formation of acetol.
研究领域:
催化化学
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材料科学
·
能源化学
✓ 已验证
产品关联
DOI
高影响因子
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
·
2023
·
IF 7.2
Zhoujie Liang,Yu Zhang,Guojie Zhang,Jun Liu,Yajing Cai,Ying Wang,Yuqiong Zhao,Guoqiang Li,Kunlun Bei
In this paper, a series of cobalt catalysts modified by different lanthanide metals were synthesized via co-impregnation method using inexpensive industrial-grade alumina as a support for dry reforming of methane. The effect of lanthanide metals as accelerators of cobalt-based catalysts on catalytic performance and anti-coking properties was mainly investigated. The textural relationships between the catalytic performance and physicochemical properties of cobalt-based catalysts doped with different lanthanide metals were further investigated. Different characterization techniques demonstrate the positive effect of lanthanide metals on the physicochemical properties of catalysts. The results show that the electron transfer between cobalt species and lanthanide metal oxides is significantly enhanced due to the introduction of lanthanide elements. The process generates more active sites, which is favorable for the adsorption and activation of methane. In addition, the abundant medium basic sites and oxygen vacancies on the surface of cobalt-based catalysts with the effect of lanthanides promoted the adsorption and activation of carbon dioxide and the gasification of carbon accumulation, which greatly improved the anti-carbon accumulation performance of the catalysts. Therefore, the prepared cobalt-lanthanum-based catalysts showed the best catalytic effect and have great potential for application.
研究领域:
催化化学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2025
·
IF 9.7
Chao Zhang,Yongsheng Gao,Haipeng Wang,Lulu Jiang,Delu Zhang,Shujun Ming,Guangying Fu,Chao Wang,Zhiguo Lv
The dry reforming of methane (DRM) could convert CH 4 and CO 2 into syngas, offering potential for greenhouse gas mitigation. However, DRM catalyst sintering and carbon deposition remain major obstacles. In this study, a highly dispersed PtNi alloy@Zr-doped 3D hollow flower-like MgAl 2 O 4 (AMO) spheres was prepared through a hydrophobic driving strategy. During a 50-hour test at 550 °C, the catalyst exhibited no significant decline in CH 4 and CO 2 conversion rates, demonstrating its excellent anti-sintering and anti-coking performance. The unique anti-coking performance can be attributed to Zr-induced oxygen vacancies, which enhance oxygen mobility and reduce carbon deposition. Besides, doped Zr increases basic active sites, enhancing CO 2 adsorption and activation, thus accelerating carbon species conversion. At 700 °C, the unique synergy between highly dispersed Pt and Ni enabled CH 4 and CO 2 conversion rates to reach 67.5 % and 73.8 %, respectively. The incorporation of Pt or Zr extends the Ni–Ni bond and partially coordinates with Ni, enhancing the stability of the Ni lattice. The reaction of CH 4 and CO 2 follows the Langmuir-Hinshelwood (L-H) mechanism, where both reactant molecules are adsorbed and activated on the metallic sites. Moreover, the effective energy barrier for the CH oxidation pathway is lower by 0.16 eV than that for the C oxidation pathway, which helps suppress the formation of carbon deposits.
研究领域:
催化化学
·
材料科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Molecular Catalysis
·
2022
·
IF 5.089
Rongzhao Li,Chengtao Zhang,Shuo Li,Yupeng Du
Propane dehydrogenation is commonly operated at temperatures exceeding 600 °C due to thermodynamic requirements. However, high temperature accelerates the deactivation of catalysts because of the coke deposition. Therefore, it is quite necessary to develop catalysts with high catalytic activity and improved anti-coking ability. To this end, an Al-doped Cr 2 O 3 catalyst derived from MIL-101(Cr/Al) is prepared in this work. The preparation conditions, including the carbonization temperature of MIL-101 and the proportion of Cr/Al, are optimized via experimental studies. Meanwhile, the adsorption and dehydrogenation behaviors of propane on the catalyst are investigated using Density Functional Theory (DFT) methods. Findings indicate that the optimum carbonization temperature and Cr/Al proportion are 900 °C and 6:4, respectively. Under the reaction condition of P = 0.1 MPa, T = 580 °C and GHSV = 800 h −1 , the propane conversion and propylene selectivity on the Cr 6 /Al 4 catalyst are 19.5% and 92.0%, respectively. The activity stability of the Al-doped Cr 2 O 3 is elongated significantly due to the lower desorption energy of propene and higher energy barrier for the coke formation on the catalyst. In sum, the present work completed via experiments and DFT calculations will lead to a better understanding of the Al-doped Cr 2 O 3 catalyst and guide the rational design of anti-coking catalysts for propane dehydrogenation.
研究领域:
化学工程
·
催化材料
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）