CATALYSIS TODAY
·
2018
·
IF 4.667
Mengke Liu,Yingnan Zhao,Huawang Zhao,Xianghui Li,Yuhan Ma,Xin Yong,Hong Chen,Yongdan Li
A number of M-Cu-ZSM-5 (M = La, Ni, La-Ni) samples were prepared via an aqueous solution ion-exchange method. The co-doping with Ni and La into a Cu-ZSM-5 catalyst enhanced the NO decomposition activity in a temperature range 350–550 °C. The characterization results indicate that doping with La effectively improved the dispersion of the Cu species forming more Cu 2+ ions in the sample, while the effect of Ni is likely to facilitate the implantation of Cu 2+ to form (Cu 2+ -O 2– -Cu 2+ ) 2+ dimers. The synergistic effect of La and Ni contributes to the increased (Cu 2+ -O 2− -Cu 2+ ) 2+ content in the co-doped sample, thus enhancing the NO decomposition activity.
研究领域:
催化化学
·
环境科学
✓ 已验证
DOI
高影响因子
ACS ES&T Engineering
·
2022
·
IF 0
Yaoyu Zhang,Yuxiong Wang,Yue Liu,Huimin Xu,Qingji Ying,Zhongbiao Wu
Cerium-modified Cu/ZSM-5 catalysts were employed for the selective catalytic combustion of acetonitrile. It was obtained that cerium addition effectively improved the mineralization rate of acetonitrile and nitrogen selectivity as well. The optimal Cu5Ce8/ZSM-5 sample exhibited 100% mineralization rate and higher than 95% nitrogen selectivity within 325–500 °C. The strong interaction between Cu and Ce species was induced in a core–shell-like structure of Cu–Ce/ZSM-5 samples, where the Cu–Ce/ZSM-5 core was wrapped with a Cu–Ce mixed oxide layer. The external mixed oxides exhibited enhanced reducibility and increased active oxygen species. In situ diffuse reflectance infrared Fourier transform spectroscopy and density functional theory simulations revealed that surface cerium species strengthened the hydrolysis reaction path of acetonitrile as ceria could effectively promote the dissociation of water and the hydrolysis of cyano groups, thereby generating a sufficient amount of NHx species. As a result, the NOx from acetonitrile overoxidation would be eliminated through internal selectivity catalytic reduction over the Cu–Ce/ZSM-5 core.
研究领域:
环境科学
·
催化化学
✓ 已验证
产品关联
DOI
BIORESOURCE TECHNOLOGY
·
2021
·
IF 9.642
Jingyuan Shang,Guangbin Fu,Zhenping Cai,Xiang Feng,Yongxiao Tuo,Xin Zhou,Hao Yan,Chong Peng,Xin Jin,Yibin Liu,Xiaobo Chen,Chaohe Yang,De Chen
Valorization of biomass to olefin or aromatics harbours tremendous practical value due to growing concerns about sustainable production of chemicals. Herein, the olefin or aromatics yields of ex-situ catalytic pyrolysis of pine can be regulated by impregnating Sn on hollow-structured ZSM-5 (M-ZSM-5) and microporous ZSM-5 catalysts in fixed-bed reactor, respectively. Results showed that Sn/ZSM-5 catalyst simultaneously increased medium acidic sites and maintained strong acidic sites, which obtained the maximum carbon yield of aromatics (33.77%) due to enhanced cracking and deoxygenation reactions. In addition, Sn boosted alkylation between olefin and aromatics, generating more alkylbenzene. In contrast, Sn/M-ZSM-5 catalyst produced the highest olefins carbon yield (12.39%) because the reduction of strong acidic sites and microporous volume inhibited the olefin aromatization. Moreover, olefins were easier to desorb from Sn/M-ZSM-5 due to the enhanced mass transfer ability, which weakened the alkylation reactions. The synergistic effect harbours great significance to manipulate the distribution of products.
研究领域:
化学工程
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能源科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Journal of the Taiwan Institute of Chemical Engineers
·
2020
·
IF 4.794
Xiaowei Fang,Ze Wang,Wenli Song,Songgeng Li
In this paper the aldol condensation of furfural (C5) with acetone (C3) over Ca/ZSM-5 was studied with lower dosages of water and acetone as compared to previous studies. It was observed that the formation of CaO over the catalyst is critical to catalyst activity and that the reaction may not occur without water. Although higher quantity of water was favorable for the formation of 4-(2-Furyl)-3-buten-2-one (C8), it was inhibitive for the formation of 1,5-bis-(2-furanyl)-1,4-pentadien-3-one (C13). Highest yields of C8 (38.4 mol%) and C13 (60.2 mol%) were obtained with C3-to-C5 mole ratio of 0.8:1, and water content of 29.7 wt%. The deactivated catalyst was further regenerated by re-loading CaO. An intrinsic kinetic model was established whereby the reaction was first-order dependent on the concentration of each reactant. The formation of 4-(2-furyl)-4‑hydroxy‑butan-2-one (C8-OH), and the C8-OH-to-C8 dehydration were essential steps. The reaction of C8-OH with C5 owned the highest activation energy (41.9 kJ/mol), this step was more sensitive to reaction temperature than those of other steps.
研究领域:
化学工程
·
催化化学
✓ 已验证
产品关联
DOI
高影响因子
ENERGY & FUELS
·
2022
·
IF 4.654
Jing Li,Suxia Ma,Rongji Cui,Nuo Xu,Ting Pei
Solid waste fly ash can encroach on land, contaminate the environment, and jeopardize human health. An alkali fusion method combined with a hydrothermal method was adopted to prepare fly ash-derived ZSM-5 molecular sieves, and a series of Fe/ZSM-5 catalysts were also prepared to test their catalytic performance in NO oxidation with H2O2. Moreover, the characteristics of catalysts synthesized by fly ash, as well as the relationship between the structure and the catalytic activity, were analyzed in detail through multiple characterization approaches. The results gave important insights into the active sites of catalytic oxidation. They concluded that 10% Fe/ZSM-5 had the best catalytic activity in which Fe sites and Brønsted acid sites collectively provided the catalytic functionality, and 92% NO removal efficiency was obtained achieved under optimal experimental conditions. This work provided a new way for recycling fly ash and developing low-cost catalysts for NO removal.
研究领域:
环境科学
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催化化学
✓ 已验证
DOI
高影响因子
Catalysis Science & Technology
·
2019
·Vol. 10
·期 3
·835-843
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IF 5.726
Yan Zhang,Shide Wu,Xia Xu,Heqing Jiang
Rapid deactivation by coke deposition is the main obstacle of ethane aromatization over Zn/ZSM-5. In this work, using the prepared nanosized Zn/HZSM-5, an almost threefold product yield and significantly improved stability were achieved in comparison with those of the microsized catalyst. XRD and XPS analyses indicated that a higher percentage of reactive [ZnOZn]2+ species was maintained during ethane aromatization over nano-Zn/HZSM-5 than micro-Zn/HZSM-5. In addition, the evolution of carbon deposits over nanosized and microsized Zn/ZSM-5 was investigated during prolonged ethane aromatization reaction using Raman spectroscopy and thermogravimetry measurements. Compared to the microsized catalyst, the nanosized zeolite facilitated the faster escape of light aromatics and the precursors of carbon deposits from the zeolite pores, thus suppressing the accumulation of coke deposits and improving the catalyst stability. Based on the nanosized Zn/HZSM-5, a protocol of isothermal reaction followed by regeneration was developed by periodically removing carbonaceous deposits, and an ∼25–35% product yield was achieved after 10 reaction–regeneration cycles.
研究领域:
催化化学
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材料科学
✓ 已验证
DOI
高影响因子
JOURNAL OF ANALYTICAL AND APPLIED PYROLYSIS
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2017
·
IF 3.471
Yunwu Zheng,Fei Wang,Xiaoqin Yang,Yuanbo Huang,Can Liu,Zhifeng Zheng,Jiyou Gu
The main objective of this work was to study aromatics production via the catalytic pyrolysis upgrading of biomass using metal-loaded modified H-ZSM-5. M-ZSM-5 catalysts were prepared through the impregnation method with Zn, Ga, Ni, Co, Mg and Cu. The prepared M-ZSM-5 catalysts were evaluated by x-ray diffraction, thermal desorption spectroscopy and scanning electron microscopy. The properties, composition and product distribution of bio-oil were also analysed. Results showed that the M-ZSM-5 catalysts yielded a higher amount of non-condensable gas at the expense of the liquid yields. The Ga-ZSM-5 catalysts produced the highest yields of bio-oil (25.76 wt%), but the lowest amount of coke (22.08 wt%) compared with the unmodified ZSM-5 catalyst (33.38 wt%). The content of the single-ring aromatics prepared by using the Zn-ZSM-5 catalysts was the highest at 90.28 wt%, whereas that of the polycyclic aromatic hydrocarbon prepared by the Ni-ZSM-5 catalysts was the highest at 31.36 wt%. Moreover, the selectivity of the single-ring aromatic hydrocarbons, such as C7 and C8, were significantly affected by the use of the M-ZSM-5 catalysts. The Zn-ZSM-5 catalysts were the most selective for toluene and xylenes with contents of 36.52 wt% and 35.32 wt%, respectively, whereas the Co-based catalysts were the most selective for indene. The Ni-based catalysts can obviously improve the selectivities of benzene production and C10+ polycyclic aromatic hydrocarbons. Zn-ZSM-5 was the most effective catalyst that can be used in the production of aromatic hydrocarbons.
研究领域:
能源化学
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催化材料科学
✓ 已验证
DOI
高影响因子
RENEWABLE ENERGY
·
2021
·
IF 8.001
Nishu,Chong Li,Meiyun Chai,Md. Maksudur Rahman,Yingkai Li,Manobendro Sarker,Ronghou Liu
Hemicellulose was extracted from rice straw, and catalyst ZSM-5 was modified by NaOH and Ni over alkaline treatment and wet impregnation method, respectively. To investigate the effects of modified ZSM-5 on selectivity of aromatic hydrocarbons, catalytic pyrolysis of hemicellulose was studied via Py-GC/MS. Significant effect has been reported for product selectivity and composition over the modified catalysts. All the modified catalysts showed better aromatic selectivity than parent ZSM-5 (P-ZSM-5). Notably, alkali modified ZSM-5 with 0.4 M concentration of NaOH (0.4 M ZSM-5) showed 36% selectivity towards aromatics with the share of benzene, toluene, and xylene (58%) and share of polyaromatics (15%) compared to others. Meanwhile, 8 wt% Ni-ZSM-5 showed the highest selectivity of aromatic hydrocarbons of 54% where the share of benzene, toluene, and xylene was 70%. This research revealed that metal modified ZSM-5 significantly influences the aromatics yield, which is essential for the production of liquid fuels and chemicals.
研究领域:
能源与环境科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
RENEWABLE ENERGY
·
2023
·
IF 8.7
Mengxue Song,Chonghao Qiu,Pengfei Ma,Jiawei Zhong,Zhuohan Zhang,Weiping Fang,Wenjing Song,Jianqiang Fan,Weikun Lai
Reductive etherification is an attractive and practical strategy to convert bio-platform compounds into valuable chemicals. In directed synthesis of furfuryl ethers, reductive etherification of bioderived furfurals is still challenging due to the complexity of catalytic reaction . Herein, reductive etherification of furfural with alcohol was investigated over Ni/ZSM-5 catalyst, which found that Si/Al ratios in ZSM-5 played an important role on the catalytic performance. For Ni/ZSM-5 with Si/Al ratio of 50, 80.9% yield of furfuryl ether at 90.8% conversion of furfural was achieved under the condition of 2 MPa H 2 and 180 °C for 3 h in isopropanol. The catalyst exhibited superior stability and recyclability during the consecutive cycle run. Catalysts characterization demonstrated that both acidic properties and furfural adsorption were influenced by the Si/Al ratios in Ni/ZSM-5, which correlated to the reaction route and catalytic performance. Lewis acid sites enhanced furfural hydrogenation into furfuryl alcohol, while Brønsted acid sites on ZSM-5 effectively catalyzed sequential etherification of furfuryl alcohol to furfuryl ether. Under optimization conditions, various furfuryl ethers could be obtained with yields above 80% over Ni/ZSM-5 catalyst in different primary alcohols, demonstrating the general versatility of the approach. Our findings offered opportunities to develop an efficient furfuryl ethers synthesis method .
研究领域:
催化化学
·
能源化学
·
绿色化学
✓ 已验证
产品关联
DOI
高影响因子
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
·
2020
·
IF 4.939
Zhaowei Li,Xiaosong Yang,Yingxiang Han,Long Rong
The conversion of biomass to produce high-valued chemical aromatic intermediates such as benzene (B), toluene (T), ethylbenzene (E), xylene (X), naphthalene (N) has attached booming interests. Herein, in order to obtain BTEXN aromatics on the hydrocracking of Jatropha oil, several LaNiMo/ZSM-5 catalysts (La loading from 0.5 to 15 wt%) by alkali treatment and metal impregnation methods were synthesized and investigated. Fundamentally, we found the alkali treatment engendered more mesoporosity to ZSM-5 and resulted in higher catalytic activity . It bears emphasis that further metal impregnated catalyst NiMo/ZSM-5 could improve the aromatics yield due to the increase of metal active sites and acidity sites. Besides, we noted that La loading had positive effects on coke reduction, catalytic stability and catalyst lifetime. To sum up, results confirmed the favorable 1 wt% La–NiMo/ZSM-5 had maximum 75 wt% BTEXN yield, longer catalyst lifetime for 100 h and decreased carbon deposits by 1.11%.
研究领域:
化学工程
·
催化材料科学
✓ 已验证
产品关联
DOI
高影响因子
FUEL
·
2024
·
IF 6.7
Mei Ren,Jun Li,Manhong Huang,Donghui Chen,Xuelian Chen,Qi An,Songmei Sun
The escalating environmental issues resulting from waste plastic necessitate innovative decomposition methods that optimize conversion rates and product selectivity. In this study, we demonstrate that linear low-density polyethylene (LLDPE) can be effectively hydrothermolyzed into C1 − C4 compounds with a selectivity of 100 % in the presence of trace water on H-ZSM-5 catalyst under a relatively low temperature of 220 °C. Water plays a dual role here as both a solvent and a reactant. It was found the density of Brønsted acid sites is crucial for LLDPE decomposition, serving as the primary active centers for cracking LLDPE chains. In-situ EPR studies indicate a synergistic mechanism of free radical and carbenium ion pathways in LLDPE depolymerization. Density Functional Theory (DFT) simulations show that the depolymerization starts with the cleavage of a C–C bond in polyethylene, instigated by a hydrogen radical from the Brønsted acid site, leading to various intermediate stages for the formation of tert -butanol, acetone and acetic acid from two potential pathways. The presence of water is crucial in these pathways, aiding bond breakages and the creation of oxygenated products in the Brønsted acid site. This study represents a substantial leap forward in sustainable methodologies for upcycling plastic waste.
研究领域:
环境科学
·
催化化学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
Chem Catalysis
·
2024
·
IF 11.5
Bin Chen,Shui Yang,Longmei Shang,Yiling Wu,Youting Wang,Jian Tian,Jiale Huang,Xiaodong Zhang,Qingbiao Li,Guowu Zhan
Biomass resources can be converted to biochemicals via the catalytic pyrolysis process, but conventional catalysts often suffer from severe deactivation due to coke formation. Here, a ternary Ni/bio-Z5 catalyst was constructed by integrating ZSM-5 and Ni components on a porous bio-SiO2 platform derived from rice husk. The Ni/bio-Z5 achieved 76% aromatic selectivity for the catalytic pyrolysis of soybean oil, corresponding to a space-time yield as high as 154.8 garom · h−1 · gcata−1. It is confirmed that the bio-SiO2 platform shortened the surface diffusion path of aromatics by co-diffusion, which then inhibited coke formation and significantly improved the catalyst stability. Moreover, the atomically dispersed Ni on ZSM-5 effectively promotes the aromatization of C2=-C6= by enhancing adsorption and acting as an oligomerization center for isoalkyl carbenium ions. The coupling of deoxygenation and aromatization reactions promotes the enhancement of aromatic selectivity through the formation of methyl-substituted cyclopentenone that can be readily converted to aromatics.
研究领域:
能源与环境科学
·
催化化学
✓ 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）