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
JACS Au
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2025
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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
APPLIED CATALYSIS B-ENVIRONMENTAL
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2023
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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
SEPARATION AND PURIFICATION TECHNOLOGY
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2023
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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
Journal of CO2 Utilization
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2017
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IF 4.292
Chen Zhang,Haiyan Yang,Peng Gao,He Zhu,Liangshu Zhong,Hui Wang,Wei Wei,Yuhan Sun
A series of Cu/ZnO/Al 2 O 3 catalysts with the total weight percentage of Cu and ZnO from 9.94 wt.% to 44.5 wt.% have been prepared by ammonia deposition −precipitation method and tested for methanol synthesis from CO 2 hydrogenation. A Cu/Zn/Al layered double hydroxides (LDHs) precursor can be formed in situ on the surface of microspherical Al 2 O 3 which acts as both support and sole source of Al 3+ cations. With increase of total Cu and ZnO loading, the dispersion of copper and reducibility of CuO decline continuously, while the exposed copper surface area increases gradually. In addition, the formation of LDHs results in a stronger both basicity and acid strength on the catalyst surface. It is found that the CO 2 conversion increases linearly with increase of the Cu and ZnO loading. The methanol selectivity for the catalyst with low total metal loading (9.94 wt.%) is much lower than those for other catalysts, though it increases with increasing loading, which can be mainly assigned to the much smaller Cu particle size (<5 nm) and the higher ratio of isolated CuO phase. Moreover, the Cu/ZnO/Al 2 O 3 catalyst with relatively high total metal loading (44.50 wt.%) still exhibits a considerable stable catalytic performance due to the formation of LDH structure.
研究领域:
催化
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化学工程
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材料科学
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环境化学
✓ 已验证
产品关联
DOI
高影响因子
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