JOURNAL OF MEMBRANE SCIENCE
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2021
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IF 8.742
Hanhan Chen,Xiaobin Wang,Yi Liu,Tengfei Yang,Naitao Yang,Bo Meng,Xiaoyao Tan,Shaomin Liu
Despite many methods available to synthesize MOF membrane, the cost-effective synthesis with high reproducibility and scalability is still a challenge. We present here a homologous support-induced approach for the growth of ZIF membrane supported on the dual-layer ZnO–Al2O3 hollow fibers, which has the potential for applications at larger scales. The developed unique dual-layer hollow fibers consisting of a thin outer ZnO layer firmly attached onto an inner porous alumina substrate were realized through one-step co-extrusion/sintering technique. During the MOF membrane synthesis, ZnO can be used not only as the support, but also as the nucleation sites and growth centers for the ZIF-8 membrane formation. More importantly, ZnO can act as a transitional bridge to direct the membrane growth outward along the support and inward embedded into the support, which significantly improving the binding force between the support and MOF, thus bringing in the outstanding membrane stability. Permeation of single gas and separation of binary mixtures revealed that the prepared membranes were free of defects. The resultant ZIF-8 composite membrane exhibits good hydrogen separation performance and excellent reproducibility. This protocol can achieve an easy and large-scale synthesis. In addition to ZIF-8 membrane, ZIF-67 membrane was also successfully synthesized via this method, which may provide some general guidelines for the preparation of other MOF membranes.
研究领域:
材料科学
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化学工程
✓ 已验证
DOI
高影响因子
JACS Au
·
2025
·
IF 8.7
Xuan Bie,Yukun Pan,Xiaowei Wang,Shiyu Zhang,Jiahui Hu,Xiaoxiao Yang,Qinghai Li,Yanguo Zhang,Robert E. Przekop,Yayun Zhang,Hui Zhou
Gas sources rich in CO2 derived from biomass/waste gasification, anaerobic digestion, or industrial carbon capture often contain impurities such as H2S, H2O, and NH3, which can significantly hinder catalyst performance. Here, we show the role of NH3 on the reverse water–gas shift (RWGS) reaction over a commercial Cu/ZnO/Al2O3 catalyst, examining its effects on both the catalytic activity and the catalyst structure. We found that NH3 reversibly decreases CO2 conversion immediately by suppressing carbonate hydrogenation and CO desorption. This effect intensifies with an increase in NH3 concentration but decreases at higher temperatures. However, prolonged exposure (over 100 h) to RWGS conditions in the presence of 1.4% NH3 leads to near-total and irreversible deactivation of the Cu/ZnO/Al2O3 catalyst. Under NH3 exposure, the catalyst loses Cu+ sites on the surface, causing a spatial separation of Cu and ZnO. Finally, to address this challenge, we propose a novel strategy to mitigate NH3 inhibition by decomposing NH3 into N2 and H2.
研究领域:
化学工程
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催化科学
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环境科学
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产品关联
DOI
PubMed
高影响因子
APPLIED CATALYSIS B-ENVIRONMENTAL
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2024
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IF 20.2
Haitao Yan,Didi Li,Zhaocong Jiang,Haoyuan Gu,Mengyuan Zhu,Yi-Fan Han,Minghui Zhu
Cu-based catalysts have been extensively used in the methanol steam reforming (MSR) reaction owing to low cost and high efficiency. In this work, we investigated the promotional effect of Fe on the Cu/ZnO/Al 2 O 3 catalysts prepared by an incipient-wetness impregnation method using a series of (quasi) in situ characterization techniques. The form of the Fe species was found to strongly depend on the Fe content. Fe species are present as highly dispersed FeO x in small amount of Fe with improved the dispersion of Cu. As Fe content increases, Fe species gradually transition to CuFe alloy and eventually to Fe 3 O 4 particles, leading to a decrease in Cu dispersion. With the gradual increase in Fe content, the apparent activity shows a volcanic trend, with CuAl-0.1Fe showing highest activity, whereas the intrinsic activity gradually decreases. Compared with CuAl- x Fe, adding moderate Fe to Cu/ZnO/Al 2 O 3 promotes the dispersion of Cu and Zn, forming abundant Cu-ZnO x interfacial sites, which improves both apparent and intrinsic activities. The best catalytic performance was obtained with the CuZnAl-0.1Fe catalyst, achieving the highest H 2 production rate of 134.7 mmol g cat −1 h −1 at 200 °C. This study reveals the role of Fe in Cu-based catalysts for MSR and inspires the design of improved Cu-based catalysts.
研究领域:
催化化学
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
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2024
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IF 8.1
Guiming Xie,Xingyang Bai,Yanrui Niu,Zhangjun Bai,Qingyuan Yang,Jian Liu,Zhou-jun Wang
ZIF-8 was employed as partial Zn source to prepare high-performance Cu/ZnO/Al 2 O 3 catalysts for methanol synthesis via carbon dioxide (CO 2 ) hydrogenation. Among the CuZnAl-x catalysts (x = 1, 0.75, 0.5, 0.25 and 0, denoting molar ratio of ZIF-8/(ZIF-8 + Zn(NO 3 ) 2 ·6H 2 O), the CuZnAl-0.5 catalyst possessed the highest space time yield of methanol ( STY MeOH ), which recorded 416.4 g MeOH kg cat −1 h −1 at 250 °C and 3.0 MPa. Using ZIF-8 as partial Zn source was found to increase the specific surface area, induce oxygen vacancies, intensify metal-oxide interactions and enrich medium basic sites, which may rationalize the excellent methanol synthesis activity of the CuZnAl-0.5 catalyst. Besides, the CuZnAl-0.5 catalyst showed good stability for 30 h of reaction. This work offers a unique route to fabricate catalysts with the aid of MOFs precursors and highlights the significance of oxygen vacancies in methanol synthesis catalysts.
研究领域:
化学工程
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催化材料科学
✓ 已验证
DOI
高影响因子
JOURNAL OF CHEMICAL TECHNOLOGY AND BIOTECHNOLOGY
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2014
·Vol. 90
·期 3
·415-422
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IF 2.494
Yanping Chen,Yiming Xu,Dang-guo Cheng,Yingcai Chen,Fengqiu Chen,Xiaoyong Lu,Yiping Huang,Songbo Ni
BACKGROUND The synthesis of C 2 –C 4 hydrocarbons from coal or biomass-derived syngas has received increasing attention because of the resource constraints of petroleum. The present study explores direct production of hydrocarbons from syngas over bifunctional catalyst containing methanol synthesis catalyst CuO–ZnO–Al 2 O 3 (CZA) and SAPO-34 zeolite. RESULTS The synthesis of C 2 –C 4 hydrocarbons from syngas was investigated over CZA/SAPO-34 bifunctional catalyst at temperatures ranging from 240 to 440°C. The results indicate that higher temperatures aggregate Cu metal and lead to the deactivation of CZA. The predominant products are dimethyl ether (DME) and methanol at temperatures from 280 to 360°C and a small amount of hydrocarbons are found due to the deactivation of SAPO-34 caused by a type of coke named ‘inert coke’. While 96.5% selectivity of C 2 –C 4 hydrocarbons in products of all hydrocarbons can be obtained at 400°C with less coke named ‘active coke’. CONCLUSION Reaction temperatures have significant effect on the selectivity of C 2 –C 4 hydrocarbons and coke species of SAPO-34. The ‘active coke’ of poly methyl-substituted benzene/naphthalene (MB/MN) acts both as an intermediate and as coke deposition. The ‘inert coke’ of poly methyl-substituted adamantine (MA) and other groups-substituted benzene/naphthalene acts only as coke depositions. Comprehensive consideration of the characteristics of this bifunctional catalyst, shows that a moderate temperature for C 2 –C 4 hydrocarbons synthesis from syngas might be approximately 400°C. © 2014 Society of Chemical Industry
研究领域:
化学工程
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催化化学
✓ 已验证
产品关联
DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
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2024
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IF 8.1
Xiaoxia Zhang,Zhipeng Zhou,Junjie Liao,Liping Chang,Jiancheng Wang,Weiren Bao
The ultra-deep removal of thiophene from coke oven gas (COG) is critical for the conversion of COG to methane. Currently, Cu/ZnO/Al 2 O 3 is considered as a promising sorbent for thiophene removal; however, its desulfurization performance is currently unable to meet the requirements for industrial applications. Here, a zirconium modification strategy is proposed to overcome this problem, allowing zirconium loaded copper-based sorbents (Cu/ZnO/Al 2 O 3 /ZrO 2 ) with significantly improved thiophene removal performance and high activity to be obtained. Characterization results showed that zirconium improved both the dispersion of copper and the concentration of Lewis acid sites on the sorbent surface. A ZrO 2 concentration of 2 % resulted in stronger Cu-Zn interaction, and the dispersion of Cu on the surface of the sorbent reached its maximum value (49.20 %). Additionally, the Lewis acid strength was also maximized, which greatly improved the desulfurization activity and resulted in a breakthrough adsorption capacity of thiophene (Q b-thiophene ) of 36.24 mg/g, which was about 17 % higher than that of the unmodified Cu/ZnO/Al 2 O 3 sorbent. These results demonstrate that the sulfur capacity of the sorbent can be increased by increasing the number of acidic sites on its surface, paving the way for ultra-deep thiophene removal in industrial applications.
研究领域:
化学工程
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环境科学
✓ 已验证
产品关联
DOI
高影响因子
APPLIED CATALYSIS B-ENVIRONMENTAL
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2023
·
IF 22.1
Xiaojing Cui,Yequn Liu,Wenjun Yan,Yanfeng Xue,Yangang Mei,Jiamei Li,Xiaoqing Gao,He Zhang,Shanhui Zhu,Yulan Niu,Tiansheng Deng
Suppressing reverse water-gas-shift (RWGS) reaction is high desirable but challenging and underdeveloped for Cu/ZnO catalysts, particularly for commercial Cu/ZnO/Al 2 O 3 catalysts. Different from the current methodologies to reduce RWGS reaction, we report a simply surface silylation method for efficiently minimizing RWGS reaction over a commercial Cu/ZnO/Al 2 O 3 catalyst. This method suppresses STY CO (Space-time yield) from 97.4 to 0.7 g CO ·kg cat −1 ·h −1 , improving STY MeOH from 20.2 to 39.9 g MeOH ·kg cat −1 ·h −1 and methanol selectivity from 15.1 to 92.9 mol%. The combination of characterization methods and density functional theory calculations provide insight into the suppressing mechanism of surface silylation on catalyst. A hydroxyl (on ZnO)-promoted RWGS reaction cycle is discovered, which can be efficiently inhibited by the consuming of hydroxyls via surface silyation. Our results provide a way to regulate RWGS reaction on Cu/ZnO-based catalysts and are expected to the further use of silylation strategy to tune the interconversion of CO and CO 2 via RWGS/WGS reaction on hydrogenation catalysts.
研究领域:
催化化学
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材料科学
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理论计算化学
✓ 已验证
产品关联
DOI
高影响因子
DIAMOND AND RELATED MATERIALS
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2023
·
IF 4.1
Weidong Sang,Xuefeng Yang,Haitao Tian,Jialin Wang,Yuchang Wang,Zhengxin Li
During the process of sintering diamond/ceramic composites, the wettability between diamond and the ceramic matrix is poor, and there are many irregular pores in the composites, which leads a low bending strength of the composites and easy shedding of diamond. In order to solve these problems, SiO 2 -B 2 O 3 -Li 2 O-ZnO-Al 2 O 3 glass-ceramic coated diamond was prepared by a sol-gel method, and the properties of the coated diamond abrasive particles were studied. The SBLZA glass-ceramic-coated diamond exhibited high thermal stability and excellent oxidation resistance, making it a good protective material for diamond. The oxidation resistance of the SBLZA glass-ceramic-coated diamond was determined by thermogravimetric analysis (TGA). The uncoated diamond abrasive particles began to oxidize at 723 °C, while the coated abrasive particles were resistant to oxidation at temperatures up to 1000 °C. The glass-ceramic coating significantly improved the bonding between diamond and the ceramic matrix. The use of SBLZA glass-ceramic-coated diamond instead of uncoated diamond in the composites sintered at 750 °C resulted in a decrease in the volume expansion rate of the diamond/ceramic composites from 37.2 % to 28.5 %, and an increase in the bending strength from 38.4 MPa to 61.5 MPa.
研究领域:
材料科学
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涂层技术
✓ 已验证
DOI
高影响因子
Catalysts
·
2023
·Vol. 13
·期 5
·800
·
IF 3.9
Zhong Xie,Jinpei Hei,Lei Cheng,Jing Li,Xiaojie Yin,Sugang Meng
CO2hydrogenation to methanol was conducted using a set of activated carbon-supported Cu/ZnO/Al2O3catalysts (CCZA) prepared by an incipient wetness impregnation approach. The effect of the Cu/Al ratio on the physicochemical properties of the catalysts, as well as their catalytic performance, were investigated. As Cu/Al ratio increased, the metallic Cu surface area displayed a reducing trend from 6.88 to 4.18 m2∙gcat−1, while the CO2adsorption capacity exhibited an increasing trend. Meanwhile, aluminum content will have an important effect on the catalysts’ reducibility and, thus, on their catalytic performance. The CCZA-2.7-de catalyst demonstrated the highest selectivity to methanol at 83.75% due to the excellent distribution and synergistic effect of copper and zinc. Although the CO2conversion of CCZA-2.2-de and CCZA-3.5-de exceeded 10%, the CH3OH selectivity was less than 60%, which may be attributed to the larger particle sizes of ZnO and poor interactions in Cu–Zn. The present study offers a novel approach to increase the number of active sites, optimize the activated carbon-aided Cu/ZnO/Al2O3catalyst’s composition, and finally elucidate the mechanism for CO2hydrogenation to methanol.Keywords:CO2hydrogenation;CuO/ZnO/Al2O3catalyst;methanol synthesis;carbon-supported catalyst;thermocatalysis
研究领域:
催化
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化学工程
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环境科学
✓ 已验证
DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2023
·
IF 8.6
Shubin Cheng,Qian Lei,Coner Deng,Weixin Lei,Honglin Chen
A green protocol for refining industrial chemicals containing formaldehyde (FA) impurities is presented here for the first time. FA, as an unreactant or a byproduct, causes separation problems in many industrial processes. It can be removed to a level of less than 1 ppm with easily separable methanol formation using commercial Cu/ZnO/Al 2 O 3 catalyst at atmospheric pressure in the absence of external hydrogen. The formation of methanol is achieved by the transfer of hydrogen species generated with the assistance of water to free FA, affording high methanol selectivity (62 %). By investigating potential intermediates and implementing deuterium labeling experiments, together with carbon and hydrogen balance calculations, a plausible pathway of water-assisted FA removal is proposed. Moreover, the in situ generated hydrogen species can be transferred directly into unsaturated compounds for selective reduction.
研究领域:
化学工程
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催化
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环境化学
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING SCIENCE
·
2023
·
IF 4.7
Yong Liu,Xinghua Zhang,Lungang Chen,Jianguo Liu,Qi Zhang,Longlong Ma
This study explores the efficacy of a cost-effective Cu-ZnO-Al 2 O 3 catalyst for one-pot hydrodeoxygenation of guaiacol into hydrocarbons. Notably, complete conversion of guaiacol was achieved, yielding a 99.6% hydrocarbon over the robust Cu(6)Zn(3)Al(1) catalyst under the conditions of 4 MPa H 2 , 300 °C, and 8 h with a catalyst/guaiacol ratio of 0.5 g/1.0 g. In-depth catalyst characterizations unveiled the presence of oxygen vacancies within the ZnO surface layer, acting as pivotal active sites that facilitated the hydrodeoxygenation of guaiacol. Furthermore, Density Functional Theory (DFT) calculations were employed to evaluate several potential active sites, revealing that the oxygen vacancy of ZnO on the Cu surface played a crucial role. This vacancy enhanced the adsorption of intermediate cyclohexanol and markedly reduced the energy barrier for the rate-limiting step. This comprehensive investigation sheds light on the catalytic pathway and offers insights into designing efficient and sustainable biofuel production processes.
研究领域:
催化
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化学工程
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材料科学
·
能源
✓ 已验证
产品关联
DOI
高影响因子
ACS Sustainable Chemistry & Engineering
·
2020
·
IF 7.632
Qian Wang,Zhi Yu,Junting Feng,Paolo Fornasiero,Yufei He,Dianqing Li
The production of biofuel 2,5-dimethylfuran (DMF) from an important biomass platform of 5-hydroxymethyl furfural (HMF) involves a complicated reaction pathway due to the competition of C═O hydrogenation and C–O hydrogenolysis; however, the dependence of formed intermediates and catalytic sites needs to be further identified. Herein, we constructed a highly efficient and selective Cu/ZnO-Al2O3 catalyst via reduction of a CuZnAl-layer double hydroxide (LDH) precursor, aimed for studying the effect of Cu0/Cu+ species on forming different intermediates and their synergetic promotional effect on HMF hydrodeoxygenation. As expected, the dependence of formation of different intermediates on the Cu+/Cu0 ratio was observed; notably, Cu/ZnO-Al2O3 with higher Cu+/Cu0 ratio finally gave 90.1% DMF selectivity at 100% HMF conversion, more selective than CuNi/Al2O3 (59.6%) and Cu/MgO-Al2O3 (75.8%) references. By a combined study of in situ IR experiments, the observed correlation between the reaction intermediates and the Cu0/Cu+ site suggests that Cu0 tends to adsorb the C═O bond as well as hydrogen molecule, while the Cu+ site is preferable to adsorb and activate the C–O bond. With the synergy of dual active sites, the Cu/ZnO-Al2O3 catalyst showed both high activity and selectivity to DMF. This work provides deep insight into the nature of active Cu species in multiple functional group biomass platform transformation.
研究领域:
催化
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化学工程
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生物化学
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
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