JOURNAL OF CATALYSIS
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2024
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IF 6.5
Peng Zhang,Fangfang Li,Xuefang Yao,Pengze Zhang,Yukai Wu,Mengmeng Xi,Fanhui Meng,Lihua Kang,Mingyuan Zhu
The GaZrO x solid solution has been recently employed in OX-ZEO bifunctional catalysts for efficient conversion of syngas to light olefins, but it remains challenging to identify the specific contributions of Zr and Ga and to understand the detailed reaction mechanisms due to the structural complexity. To address this complexity and elucidate the active sites over the Zr-Ga oxide system, this study presents a catalyst designed by physical mixing ZrO 2 with different crystalline phases ( m -ZrO 2 & t -ZrO 2 ) and α -Ga 2 O 3 . The physical mixture of m -ZrO 2 and α -Ga 2 O 3 achieves a high CO conversion of 39.1 %, with light olefins selectivity of 87.3% among hydrocarbons after combined with SAPO-34, surpassing the performance of physical mixture of t -ZrO 2 and/or α -Ga 2 O 3 with SAPO-34. Combining the various characterizations and DFT calculations, we have confirmed that m -ZrO 2 site, enriched with oxygen vacancies and surface hydroxyl groups, is essential for CO adsorption and HCOO* intermediate formation, while the α -Ga 2 O 3 site plays a key role in the dissociation of H 2 . Furthermore, the electron transfer from m -ZrO 2 to α -Ga 2 O 3 in their mixture is more efficient than in a physically mixed t -ZrO 2 and α -Ga 2 O 3 . This accelerates the H 2 dissociation and boosts the spillover of hydrogen from α -Ga 2 O 3 to m -ZrO 2 , leading to the formation of more CH 3 O* intermediates and higher light olefins yield when combined with SAPO-34.
研究领域:
催化化学
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材料科学
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计算化学
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DOI
高影响因子
ACS Catalysis
·
2024
·
IF 11.3
Lin Zhang,Junjie Su,Chang Liu,Su Liu,Haibo Zhou,Wenqian Jiao,Yongfeng Hu,Feng Xiong,Yiqing Lu,Yingchun Ye,Xusheng Zheng,Yida Zhang,Yangdong Wang,Heyong He
Direct synthesis of aromatics from syngas (STA) over an oxide–zeolite bifunctional catalyst is promising as a petroleum alternative route. Aromatics space-time yield (STY) is a key parameter for measuring the production capacity in an industrial process. However, it is still a great challenge to achieve high aromatics STY for industrial applications. Herein, we synthesized a series of CeMnOx catalysts with a self-cleaning effect. The structures and reduction process of CeMnOx catalysts were thoroughly characterized by X-ray absorption fine structure and in situ X-ray diffraction. Changes in surface carbon species during the reaction are revealed by in situ X-ray photoelectron spectroscopy and in situ Raman spectroscopy. Our results demonstrate that the intermediates can be converted to long-chain hydrocarbon or even graphite carbon species which can cover the surface of MnOx, inhibiting the reactants from further interacting with the active sites. Ce promotion in MnOx may remove the dissociated carbon species from the oxide surface by converting excess surface carbon species into short-chain hydrocarbons; thus, the growth of graphite carbon species is inhibited. This self-cleaning effect of CeMnOx catalysts facilitates the syngas conversion via maintaining a high exposure of active sites during the reaction, especially under high pressure and temperature. The aromatics STY (on carbon base) can reach as high as 4.27 mmol g–1 h–1 over CeMnOx+HZSM-5 bifunctional catalyst, which outperforms the data previously reported.
研究领域:
催化化学
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材料科学
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能源化工
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DOI
高影响因子
Catalysts
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2019
·Vol. 9
·期 3
·218
·
IF 3.444
Shaoxia Guo,Guilong Liu,Tong Han,Ziyang Zhang,Yuan Liu
Owing to the outstanding catalytic performance for higher alcohol synthesis, Ga-Co catalysts have attracted much attention. In view of their unsatisfactory stability and alcohol selectivity, herein, K-modulated Co nanoparticles trapped in La-Ga-O catalysts were prepared by the reduction of La1−xKxCo0.65Ga0.35O3perovskite precursor. Benefiting from the atomic dispersion of all the elements in the precursor, during the reduction of La1−xKxCo0.65Ga0.35O3, Co nanoparticles could be confined into the K-modified La-Ga-O composite oxides, and the confinement of La-Ga-O could improve the anti-sintering performance of Co nanoparticles. In addition, the addition of K modulated parts of La-Ga-O into La2O3, which ameliorated the anti-carbon deposition performance. Finally, the addition of K increased the dispersion of cobalt and provided more electron donors to metallic Co, resulting in a high activity and superior selectivity to higher alcohols. Benefiting from the above characteristics, the catalyst possesses excellent activity, good selectivity, and superior stability.Keywords:perovskite-type oxide (PTO);cobalt;gallium;potassium;higher alcohols;syngas
研究领域:
化学工程
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催化材料
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产品关联
DOI
高影响因子
APPLIED SURFACE SCIENCE
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2019
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IF 5.155
Yajing Wang,Yane Zheng,Yuhao Wang,Kongzhai Li,Yaming Wang,Lihong Jiang,Xing Zhu,Yonggang Wei,Hua Wang
Chemical-looping reforming of methane (CLRM) offers an effective approach for the production of syngas . A series of Ce x Zr y Cu 1−x−y (x = 0.6, 0.7, y = 0–0.35) mixed oxides were successfully prepared by sol-gel method, and characterized by means of XRD , H 2 -TPR, BET, XPS , Raman and CH 4 -TPR. The addition of Cu and Zr ions caused the distortion of CeO 2 lattice and induced more oxygen vacancies , which promoted the mobility of lattice oxygen in the materials. Ce x Zr y Cu 1−x−y mixed oxides also owned smaller grain size and better thermal stability than pure CeO 2 -CuO mixed oxides. Among the series of Ce x Zr y Cu 1−x−y mixed oxides, the reducibility of Ce 0.6 Zr x Cu 0.4−x and Ce 0.7 Zr x Cu 0.3−x samples gradually increased with the Cu content. It was found that the Ce 0.7 Zr 0.2 Cu 0.1 sample owned the most abundant oxygen vacancies on the surface. The Ce x Zr y Cu 1−x−y mixed oxides with lower Cu content (≤0.1) produced higher amount of H 2 and CO while smaller CO 2 . Ce 0.7 Zr 0.2 Cu 0.1 sample still retained better structural stability and thermal stability after 20 times cycled reaction.
研究领域:
化学工程
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材料科学
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产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
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2023
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IF 15.1
Guangyuan Luo,Zhuoshi Li,Qingyun Liu,Shaoxia Guo,Xiaofeng Pei,Jing Lv,Shouying Huang,Yue Wang,Xinbin Ma
Higher alcohol synthesis (HAS) from syngas is a promising route for converting non-petroleum fossil energy resources into useful fuels or chemicals, while the design and preparation of highly efficient catalysts remain challenging. Herein, a series of Co 0 -Co 2 C catalysts supported on mesoporous carbon–silica composites were prepared for HAS. The composites were derived from carbon-silica nanocages, consisting of uniformly distributed carbon and silica species, which significantly affected the particle dispersion, phase evolution and catalytic performance. With increasing the carbon content, the initial carburization of cobalt was promoted, and some obtained Co 2 C tended to convert to hexagonal closest packed cobalt (hcp-Co, a highly active site for Fischer-Tropsch), boosting the CO dissociation and catalyst activity. While as the silica content increased, more Co 2 C phases can be stabilized, leading to enhanced Co 2 C/Co 0 ratio and ROH selectivity. As a result, the optimal 15Co/22Si@C catalyst achieved a ROH selectivity of 40.1% where 96.0 wt% was higher alcohols (HA), and a space time yield (STY) towards HA of 26.5 mmol·g cat −1 ·h −1 , which remarkably outperformed most of the reported Co-based catalysts in HAS. Moreover, the superior stability of over 250 h reaction was obtained, owing to the confinement effect and strong metal-support interaction provided by the mesoporous carbon–silica composites. This work may provide guidance for designing high-performance monometallic cobalt catalyst in HAS.
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DOI
高影响因子
JOURNAL OF SOLID STATE CHEMISTRY
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2018
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IF 2.179
Shi-Yuan Zhang,Yuan-Yuan Yang,Yue-Qing Zheng,Hong-Lin Zhu
Electrocatalytic reduction of CO 2 to useful fuels or chemicals is a promising path for carbon recycling. In this study, a novel mixed-metallic MOF [Ag 4 Co 2 (pyz)PDC 4 ][Ag 2 Co(pyz) 2 PDC 2 ] was synthesized, and it transformed into Ag doped Co 3 O 4 catalyst, which exhibits excellent electro-catalytic performance for reduction of CO 2 in water to syngas (H 2 + CO). The as-prepared Ag/Co 3 O 4 material exhibits a high selectivity of CO in 0.1 M KHCO 3 aqueous solution (CO 2 saturated) with the corresponding faradaic efficiency up to 55.6%. Compared with the Ag/Co 3 O 4 electrode, the maximum faradaic efficiency (FE) of CO of pure Co 3 O 4 is 21.3% at − 1.8 V vs. SCE. The results show that the presence of Ag can improve the efficiency of CO significantly, thereby inhibiting the production of H 2 . The stability of the samples can be maintained for more than 10 h at − 1.8 V vs. SCE. The ratio of production between H 2 and CO can be controlled by varying the potential values.
研究领域:
材料科学
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环境科学
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化学工程
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产品关联
DOI
高影响因子
ACS Catalysis
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2016
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IF 9.307
Jie Sun,Qiuxia Cai,Yan Wan,Shaolong Wan,Li Wang,Jingdong Lin,Donghai Mei,Yong Wang
The promotional effects of a cesium promoter on higher alcohol (C2+OH) synthesis from syngas over Cs2O-Cu/ZnO/Al2O3 catalysts were investigated using a combined experimental and density functional theory (DFT) calculation method. In the presence of a cesium promoter, the C2+OH productivity increases from 77.1 to 157.3 g kgcat–1 h–1 at 583 K due to the enhancement of the initial C–C bond formation. A detailed analysis of chain growth probabilities (CGPs) confirms that initial C–C bond formation is the rate-determining step in the temperature range of 543–583 K. Addition of a cesium promoter significantly increases the productivities of 2-methyl-1-propanol, while the CGP values (C3* to 2-methyl-C3*) are almost unaffected. With the assistance of a cesium promoter, the CGPs of the initial C–C bond formation step (C1* to C2*) increase from 0.13 to 0.25 at 583 K. DFT calculations indicate that the initial C–C bond formation during syngas synthesis over the ZnCu(211) model surface is mainly due to the HCO + HCO coupling. In the presence of Cs2O, the stabilities of key intermediates such as HCO and H2CO are enhanced, which facilitates both HCO + HCO and HCO + H2CO coupling steps with lower activation barriers. In addition, Bader charge analysis suggests that the presence of cesium ions could facilitate nucleophilic coupling between HCO and H2CO for the initial C–C bond formation.
研究领域:
催化化学
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能源化学
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理论化学
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产品关联
DOI
高影响因子
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
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2013
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IF 3.548
Zebao Rui,Danyan Feng,Huayao Chen,Hongbing Ji
Highly-ordered TiO 2 nanotube array (TiNT) was prepared by an electrochemical anodization method and used as the support for Ni and Ni–M (M = Ru, Pt and Rh) bimetallic catalysts . Ni/TiNT and Ni–M/TiNT were then applied to the combination reactions of the partial oxidation of methane reaction (POM) with the carbon dioxide reforming with methane reaction (CRM) for the syngas production . The results show that Ni/TiNT suffers from the formation of NiO and NiTiO 3 , and the coke deposition. The superior catalytic performance and the enhanced resistance ability against carbon formation are obtained over a small amount of noble metal modified Ni bimetallic catalysts, which are ranked as Ni/TiNT < Ni–Ru/TiNT < Ni–Pt/TiNT < Ni–Rh/TiNT. The interaction of Ni–M, i.e., enhanced reducibility of NiO and the maintenance of metallic Ni species even in the presence of oxygen, over Ni bimetallic catalysts is regarded as an important reason. Much short distance between the exothermic and the endothermic zones over Ni–M/TiNT catalysts bed can be realized, and a flat temperature profile in the catalyst bed is expected, which in turn can relieve the hot-spot and NiTiO 3 formation to some extent.
研究领域:
材料科学
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催化化学
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产品关联
DOI
高影响因子
Catalysts
·
2023
·Vol. 13
·期 6
·948
·
IF 3.9
Rui Hu,Tianye Wang,Yifan Wang,Yuan Zhu,Li Xie,Enhui Xing,Yu Wu,Zhijian Da
A nano-hollow zeolite-encapsulating ultra-fine Fe nanoparticle catalyst denoted as Fe@n-hS-HT was successfully synthesized through a simple water steam treatment of the Fe@n-hS catalyst prepared by the “dissolution–recrystallization” (D-R) method. The Fe@n-hS-HT catalyst had a hierarchical porous structure and a high dispersion of Fe2O3particles with a size of 3.4 nm. Furthermore, the results of several characterization methods, such as XRD, HAADF-STEM, and H2-TPR, further demonstrated the transformation of the skeleton Fe in Fe@n-hS into Fe2O3, which was uniformly dispersed in the Fe@n-hS-HT catalyst. Meanwhile, Fe@n-hS-HT had significantly higher selectivity and yield of C2-C4=than the reference catalysts Fe/S and Fe@n-hS, which provided strong proof for the confined catalysis of the metal@zeolite catalyst.Keywords:hollow zeolite;Fischer–Tropsch synthesis;encapsulation;iron catalyst
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DOI
高影响因子
OPTICAL MATERIALS
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2023
·
IF 3.9
Jia Li,Jianfeng Zheng,Xingmin Liu,Yatao Yang,Xiaojin Han,Zhanggen Huang
Photoelectrochemical reduction of CO 2 with H 2 O into syngas (H 2 /CO) is considered as an important platform to organic chemicals, which can effectively alleviate the greenhouse effect and energy dependence. We synthesized SnO/g-C 3 N 4 p-n junction catalyst with matched energy band, which shows enhanced light absorption performance and photogenerated charge separation efficiency. The M − S plots verified the successful construction of p-n type heterojunctions , and the investigations of LSV , EIS , PL and transient photocurrents test indicate that the recombination rate of charge is well inhibited by the design of p-n heterojunction. In this work, the syngas derived from PEC reduction of CO 2 and H 2 O is achieved by the SnO/g-C 3 N 4 photocathode with a total FE of 70% at an external bias of −1.5 V. In addition, the H 2 /CO molar ratio can be tuned from 1.5 to 10 by controlling the applied voltage. The study may inspire a new thought for the design of high-performance photoelectric catalyst and a promising strategy for PEC CO 2 reduction to valuable carbon-based compounds.
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DOI
高影响因子
FUEL
·
2022
·
IF 8.035
Shuo Cao,Ying Ma,Wei Chu,Yuefeng Liu
Molybdenum carbide (MoC x ) has been considered as a promising catalyst for CO 2 reduction at medium temperature (i.e. >400 °C) because of its excellent ability to dissociate CO 2 and H 2 . However, MoC x catalysts are mainly synthesized at high carburization temperature (i.e., >650 °C), which renders its low active sites exposed and the generation of CH 4 by-product, especially at a high H 2 /CO 2 molar ratio. Herein, the core–shell structure nanodiamond @ graphene (ND@G) hybrid with enriched electron density was applied for anchoring MoC x nanoparticles . The as-synthesized MoC x /ND@G catalyst consists of ultra-high exposed MoC x nanoparticles/nanoclusters, exhibiting an extremely high and stable reverse water gas shift (RWGS) catalytic performances (211.5 μmol CO 2 g MoCx −1 s −1 at 400 °C and 358.0 μmol CO2 g MoCx −1 s −1 at 600 °C, respectively) with CO selectivity up to 99.5% at H 2 /CO 2 ratio of 4. Remarkably, the MoC x /ND@G catalyst facilitates the CO 2 activation at a relatively low temperature compared to MoC x nanoparticles supported by other typical carriers (i.e., activated carbon and γ-Al 2 O 3 ) and bulk β-Mo 2 C due to the strong interaction between MoC x species and curved graphene layers on the surface of ND@G. This study paves a practical strategy for developing a highly efficient molybdenum carbide-based catalyst for CO 2 activation.
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DOI
高影响因子
MICROPOROUS AND MESOPOROUS MATERIALS
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2022
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IF 5.876
Haochen Qi,Chuang Xing,Weiguo Huang,Mingquan Li,Yujia Jiang,Xu Sun,Heyang Liu,Peng Lu,Jiangang Chen,Shuyao Chen
Fischer-Tropsch (FT) synthesis as a strongly exothermic reaction has diffusely manufactured clean fuels from syngas. However, it is difficult to obtain the concentrated product distributions. Here, we design ZSM-5 encapsulated cobalt particles on the thermal conductivity of the SiC matrix. The Co@NaZSM-5/SiC capsule catalyst with hierarchical structure is ingeniously assembled through a solvent-free synthesis route. Due to the joint functions of acidic zeolite , SiC thermal conductivity and macropores, the olefin selectivity enhances to 32.3% on the Co@NaZSM-5/SiC catalyst. Moreover, the ratio of O 5-11 /C 5-11 approaches 49.1% suggesting the elevated middle olefin proportion. The H + ion-exchanged Co@HZSM-5/SiC capsule catalyst shows a high isoparaffin selectivity of 27.3%, since the olefin isomerization reaction is accelerated over strong acid sites. Besides, Co 2 C phase is readily formed during the FT reaction, which is an activity center for olefin synthesis. The capsule catalyst with the proper acidity, thermal conductivity, and hierarchical structure is a promising prospect for tuning production distribution in FT reaction.
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DOI
高影响因子
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