CATALYSIS LETTERS
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2019
·Vol. 149
·期 8
·2078-2088
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IF 2.372
He Xiaoxia,Chen Yu,Liu Ya,Fang Lina,Chen Zeng,Ji Hongbing
Abstract A series of metal-modified hierarchical M/H-ZSM-5 catalysts were prepared for catalytic conversion of cellulose in an aqueous medium. Characterization of the catalysts showed that the impregnation of metal into H-ZSM-5 did not change the basic framework and pore structure of H-ZSM-5, but it decreased the total acidity. Analysis of the products indicated that the catalysts significantly affected products distribution. When Co/H-ZSM-5 and Fe/H-ZSM-5 were used as the catalysts, the yields of lactic acid and cyclic ketones obviously increased. At last, a recommendable catalytic transformation pathway of cellulose over M/H-ZSM-5 was proposed on the basis of the obtained experimental results and the published literatures. Graphical Abstract In this paper, a series of metal-modified hierarchical M/H-ZSM-5 (M = Ce, Co, Ga, and Fe) catalysts were prepared and employed in catalytic conversion of cellulose in aqueous media to examined the products distribution of cellulose catalytic conversion. Based on our results and previous works, the plausible general reaction pathways of cellulose over M/H-ZSM-5 were proposed.
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
CHINESE JOURNAL OF CHEMICAL ENGINEERING
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2021
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IF 3.171
Xiao Zhao,Xuan Shi,Zhongshun Chen,Long Xu,Chengyi Dai,Yazhou Zhang,Xinwen Guo,Dongyuan Yang,Xiaoxun Ma
A series of ZnO-ZrO 2 solid solutions with different Zn contents were synthesized by the urea co-precipitation method, which were coupled with H-ZSM-5 zeolite to form bifunctional catalysts. As a new benzene alkylation reagent, syngas was used instead of methanol to realize the efficient conversion of syngas and benzene into toluene and xylene. A suitable ratio of ZnO-ZrO 2 led to the significant improvement in the catalytic performance, and a suitable amount of acid helped to increase the selectivity of toluene/xylene and reduce the selectivity of the by-products ethylbenzene and C 9 + aromatics. The highest benzene conversion of 89.2% and toluene/xylene selectivity of 88.7% were achieved over 10% ZnO-ZrO 2 &H-ZSM-5 (Si/Al = 23) at a pressure of 3 MPa and a temperature of 450 °C. In addition, the effect of the zeolite framework structure on product distribution was examined. Similar to the molecular dynamics of aromatic hydrocarbons , H-ZSM-5 zeolites comprise 10-membered-ring pores, which are beneficial to the activation of benzene; hence, the conversion of benzene is higher. H-ZSM-35 and H-MOR zeolites exhibited small eight-membered-ring channels, which were not conducive to the passage of benzene; hence, the by-product ethylbenzene exhibits a higher selectivity. The distance between the active centers of the bifunctional catalysts was the main factor affecting the catalytic performance, and the powder mixing method was more conducive to the conversion of syngas and benzene.
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
JOURNAL OF RARE EARTHS
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2022
·
IF 4.632
Feng Lin,Yudan Zhong,Yulong Ma,Yonggang Sun,Xiuqin Men,Yingbo Zhu
Hydrodeoxygenation (HDO) of renewable lignin-derived biomass in aqueous-phase to produce high value-added products is of great significance. However, developing new catalysts with high activity and excellent stability in an aqueous phase faces considerable challenges. Rare earth doping can effectively regulate the water exchange rate constant (WERC) value of the catalyst and play an important role in promoting the hydrolysis of ether bonds. Therefore, in this paper the bimetallic supported catalyst Ni–La 2 O 3 /H-ZSM-5 doped with rare earth metal La 2 O 3 was prepared, and used to catalyze the conversion of the lignin model compound guaiacol to cyclohexanol in the aqueous phase. The conversion of guaiacol catalyzed by 10Ni–3La 2 O 3 /H-ZSM-5 reaches 100%, and the selectivity of the product cyclohexanol is 85%. A series of characterizations illustrate that the doping of La 2 O 3 causes the electron transfer between La 2 O 3 –Ni and changes the distribution of Ni, and a strong metal carrier interaction occurs between the bimetallic Ni–La 2 O 3 and H-ZSM-5. This can effectively promote the hydrolysis of the C–O ether bond in guaiacol and significantly improve the activity of the catalyst. The possible catalytic reaction mechanism of Ni–La 2 O 3 /H-ZSM-5 catalytic conversion of guaiacol was proposed.
研究领域:
催化化学
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生物质转化
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能源化学
✓ 已验证
产品关联
DOI
高影响因子
RENEWABLE ENERGY
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2021
·
IF 8.001
Feng Lin,Yulong Ma,Yonggang Sun,Kanghe Zhao,Tingting Gao,Yingbo Zhu
Due to the inertness and structural complexity of lignin, upgrading lignin to biofuels and fine chemicals still faces great challenges. In this paper, a one-pot method was used to catalyze straw lignin with H-ZSM-5 supported by Ni and Ru bimetals, and the lignin conversion rate reached 88.1%. The yield of monophenol was 19.5%, of which the yield of 4-ethylphenol and 4-ethylguaiacol was 4.9% and 3.8%, respectively. The 2D HSQC NMR analysis confirmed that the Ni–Ru/H-ZSM-5 catalyst had an obvious activity of breaking C β -O bonds before and after the reaction. The result showed that after loading metal Ni and Ru, the Lewis acid of the catalytic system was greatly increased, which caused electron transfer between Ni and Ru. 3Ni-1.5Ru/H-ZSM-5 had the strongest activity due to the largest synergy among Ni, Ru and H-ZSM-5. The synergy was the key factor leading to the cleavage of C–C and C–O bonds in straw lignin and the high-performance catalytic degradation of lignin. Besides, the effect of reaction solvent and hydrogen resource on upgrading lignin to fine chemicals over 3Ni-1.5Ru/HZSM-5 catalyst was also intensively investigated. This research developed a method for the direct conversion of lignin into valuable monophenols.
研究领域:
催化化学
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生物质转化
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF CATALYSIS
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2019
·
IF 7.723
Xiaoyue Wan,Qi Zhang,Mingming Zhu,Yi Zhao,Yongmei Liu,Chunmei Zhou,Yanhui Yang,Yong Cao
Site-selective deoxygenation of hydroxyl groups represents essential processes to access valuable functionalized bio-based compounds with industrial potential. One of the challenging tasks in this context is to convert biodiesel-derived glycerol in the presence of abundant water directly to 1,3-propanediol (1,3-PDO), a key component of the emerging polymer industry. Herein, a monometallic iridium supported on H-ZSM-5 in the absence of Re oxophilic metal oxides was prepared via grinding-assisted impregnation procedures and attempted as an effective and recyclable catalyst for the aqueous-phase selective hydrogenolysis of glycerol toward 1,3-PDO in the absence of acid additives. The results revealed the necessity to control the Ir domain dispersions, Ir 0 /Ir 3+ ratio and the amounts of overall acid/Brönsted acid sites. Activity depended linearly on the amount of overall and Brönsted acid sites, and 1,3-PDO selectivity increased in the presence of Ir-induced Brönsted acid sites, denoted as Ir-O(H)-H-ZSM-5. We speculate that Ir-O(H)-H-ZSM-5 are generated by the interfacial synergistic interaction between IrO x and H-ZSM-5 through hydrogen spillover and reverse hydrogen spillover according to the reported literatures. The reaction mechanism to elucidate the role of Ir-O(H)-H-ZSM-5 sites in glycerol hydrogenolysis was also postulated based on extensive characterization and catalytic reaction results.
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
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
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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
FUEL
·
2022
·
IF 8.035
Mengjiao Xing,Yunlei Chen,Jian Cao,Yuanlong Han,Zhichao Tao,Fei Wang,Kun Hao,Ling Zhang,Wentao Zheng,Hongwei Xiang,Yong Yang,Yongwang Li,Xiaodong Wen
Understanding the catalytic structure–activity relationship over active sites is of fundamental importance in heterogeneous catalysis field. Herein, a series of H-ZSM-5 zeolites with Al pairs contents in the range of 31% to 82% are used to explore the structure sensitivity of olefin aromatization reaction. Compared with high reaction temperatures (385 ℃ and above), prominently different initial aromatic yields are observed over the samples at 150 ℃. In addition, the 1-octene temperature-programmed surface reaction (TPSR) and theoretical calculation results give a thorough understanding on active site dependent activation temperature (100 vs 150 ℃ over Al pairs and single Al). However, the catalytic cycle of olefin aromatization is not sustainable at low reaction temperature, which is due to the formation and blocking of big molecules in the micropores (e.g., trimethylbenzene etc.). In conclusion, the desorption of big molecules is the rate-determining step for olefin aromatization reaction over H-ZSM-5, which masks the structure sensitivity over Al pairs and single Al.
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
FUEL
·
2025
·
IF 7.5
Qicheng Li,Xihu Zhao,Xiaobo Song,Juan Dong,Zhitong Zhao,Pan Hao,Qi Shi,Xuekuan Li
Benzene alkylation with syngas is attractive for alkylbenzene production, which use metals/metal oxides combining H-ZSM-5 zeolites as the catalyst. Herein, the H-ZSM-5 zeolites with three different morphologies—spindle-, flake-, and nano-sized—were synthesized. Subsequently, crystal structural, textural and acidic properties of three H-ZSM-5 zeolites and their corresponding bifunctional catalysts were characterized and the catalytic reaction activity and stability of the benzene alkylation with syngas were investigated. The bifunctional catalyst derived from nano-sized zeolites demonstrates an initial benzene conversion rate of 46.7% and reduces by 71.78% after 51 h of continuous operation, owing to abundant acid sites, large surface area and mesopores diameters, and balanced acidity to promote reactant and product diffusion. The spindle-shaped zeolite catalyst delivers the highest initial benzene conversion rate (53.77%) due to abundant acid sites. However, the benzene conversion rate drops to 12.12% of the initial value after 39 h due to limited micropore volume and relatively small mesopore diameters of the catalyst. The flake-shaped zeolite catalyst exhibits the lowest initial conversion rate and the shortest lifetime (30 h) owing to the fewest accessible acid sites and the peculiar pore structure. Three cases indicate that increasing mesopore volume is conducive to improve ratio of Brønsted to Lewis acid sites (B/L), resulting in enhancement of the catalytic activity. Meanwhile, the huge micropore volume and increased mesopore diameter are positive to alleviate pore blockage and coverage of active sites due to high mass-transfer efficiency within the zeolitic channels. These textural advantages collectively contribute to a delayed catalyst deactivation process and sustained catalytic activity. This work highlights the pivotal role of the H-ZSM-5 morphology in the benzene alkylation process with syngas and facilitates the efficient development of production process for non-oil alkylbenzene.
研究领域:
催化化学
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材料化学
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石油化工
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多相催化
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纳米材料
✓ 已验证
产品关联
DOI
高影响因子
Molecular Catalysis
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2025
·
IF 4.9
Shengxin An,Shuaibo Zhao,Jingting Jin,Tao He,Yuhao Wang,Na Kong,Jie Zhou,Wenzhi Li
Great expectations have been placed on bimetallic co-modified zeolite for the direct oxidation of methane to methanol. In this work, H-ZSM-5 zeolite was modified with bimetallic copper and zinc via ion-exchange method. Numerous experiments were conducted and the methanol yield of 44,302.70 μmol·g cat −1 ·h −1 was obtained over 1Cu/2Zn-ZSM-5 catalyst. A series of characterization analyses confirmed that the introduction of Zn increased the proportion of active Cu species bound to extra-framework oxygen by altering the electronic state of copper. The bis (μ-oxo) dicopper ligand was identified as the active site for methane oxidation. The possible reasonable reaction pathway was the free radical reaction. This work provides a valuable guidance for the preparation of co-modified zeolite catalysts for the direct oxidation of methane to methanol.
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
CATALYSIS COMMUNICATIONS
·
2024
·
IF 3.4
Chenan Yang,Yi Liu,Ying Hu,Peng Wang,Yuling Yang,Shangxing Chen,Zongde Wang,Xiang Li
Catalytic valorization of biomass into high energy density fuels plays a vital role in order to achieve future carbon neutrality. Herein, a class of H-MZ-5 catalysts with different mesoporous pore structures and acid site properties were synthesized. Among them, HMZ-5 prepared with tetrapropylammonium bromide (TPABr) and hexadecyltrimethylammonium bromide (CTAB) as templating agents showed the most excellent catalytic activity and selectivity of α-pinene dimerization. Under optimal catalytic conditions, 100% α-pinene was converted with 89.6% selectivity to dimers. The efficient catalytic activity and affordability of the catalysts in this system make it promising for industrial applications.
研究领域:
化学工程
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能源科学
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催化材料
✓ 已验证
产品关联
DOI
高影响因子
APPLIED CLAY SCIENCE
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2021
·
IF 5.467
Xinyu Li,Shunyu Han,Dongdong Guan,Nanzhe Jiang,Jingzhe Xu,Sang-Eon Park
The direct synthesis of H-ZSM-5 catalysts from natural aluminosilicate clays is important for the conversion of raw clay resources to high-value-added products. Herein, the solid-like-state conversion was used to directly prepare nano-H-ZSM-5 with uniform morphology and particle size (~300 nm) from leached illite (ISR) as both Si and Al source. Crystallization kinetics indicated that the reactivity of ISR is similar to that of commercially fabricated products and ISR could be rapidly (within 5 h) converted into nano-H-ZSM-5, the crystallinity , morphology, and crystal size of which were strongly affected by the amount of tetrapropylammonium hydroxide (TPAOH). Additionally, the residual Al of ISR uniformly intruded the H-ZSM-5 framework to provide active sites for the methanol-to-aromatics reaction. The catalytic performance stability and BTX selectivity of nano-H-ZSM-5 for this reaction surpassed those of a commercial ZSM-5 catalyst because of the synergistic effect among the specific surface area and volume of micropores , uniform morphology and particle size, and homogeneously distributed acidic sites. This rapid, efficient, and cleaner synthesis reported herein was shown to have no necessity of ion exchange with ammonium salts, to be H-form of ZSM-5 as well as improve the productivity of HZSM-5 catalysts. And consequently, it is expected to reduce the cost of synthesis and provide an opportunity for the comprehensive development and utilization of illite clay resources.
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
Journal of Environmental Chemical Engineering
·
2023
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IF 7.7
Ruokun Jia,Jiayuan Deng,Xiaohang Yang,Ruisong Xue,Pengpeng Wang,Xingbo Bian,Qiyao Wang
Graphitic carbon nitride (CN) hold great promise as a photocatalyst for generating hydrogen energy via water splitting, owing to its remarkable ability to respond to visible light and its strong reduction capacity. However, the photocatalytic water splitting for H 2 evolution performance of pure CN was impeded by its low surface area, inadequate hydrophilicity, and unsatisfactory photoelectric conversion efficiency. Here we tackled these challenges by synthesizing a series of CN/H-ZSM-5 composites with varying amount of H-ZSM-5 zeolite using a straightforward thermal copolymerization method. The contact angle and N 2 adsorption-desorption measurements confirmed that the incorporated hydrophilic and porous H-ZSM-5 zeolite contribute to increased surface area and improved hydrophilicity of the CN/H-ZSM-5 composites. Meanwhile the resulting CN/H-ZSM-5 composites exhibited significant separation and migration enhancement of photoexcited charge carriers. Consequently, the optimized CN/H-ZSM-5 composite, containing 50 mg of H-ZSM-5 zeolite, demonstrated 13 times increase in photocatalytic H 2 production rate than that of pure CN. This work not only provided a competitively universal approach on the design of high-efficiency CN based photocatalyst, but also clarified the role of H-ZSM-5 zeolite in the H 2 evolution enhancement.
研究领域:
材料科学
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能源化学
✓ 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）