Molecular Catalysis
·
2024
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IF 3.9
Zhe Zhang,Jianan Zhang,Shuai Chen,Yanan Liu,Yufei He,Dianqing Li
Hydrogen spillover phenomenon can significantly impact the activity in hydrogenation reaction, but the spillover is limited in a very short range on non-reducible Al 2 O 3 , a most widely used industrial support. Herein, Al 2 O 3 doped with different lanthanides (ln) was prepared by co-precipitation, which was then used to produce Pd/ln-Al 2 O 3 catalysts. These catalysts display much higher hydrogenation activity towards alkylated anthraquinone than undoped Pd/Al 2 O 3 catalyst and those modified by non-lanthanide elements. After the introduction of lanthanides, the reaction order of H 2 decreases from 1 to 0. Further characterization and DFT calculation show that H 2 storage ability is increased for ln-doped catalysts due to the low activation energy of H transfer and low adsorption energy of H on O(-ln) sites. In addition, a reasonable relationship between reducibility of ln 3+ in catalysts and the catalytic performance is found.
研究领域:
化学工程
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催化科学
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DOI
高影响因子
ChemCatChem
·
2021
·Vol. 13
·期 19
·4133-4141
·
IF 5.686
Lina Zhang,Bangjie Zhang,Peng Xue,Jiwei Li,Zhun Zhang,Yanling Yang,Shuai Wang,Jingdong Lin,Honggang Liao,Yong Wang,Yali Yao,Shaolong Wan,Haifeng Xiong
Graphical Room temperature oxidation : Pretreatment methods affect the nature of the Pd species and the reactivity of Pd/Al 2 O 3 in formaldehyde oxidation at room temperature. The steam treatment (H 2 O/Ar) increased the metal Pd dispersion, and generated more active hydroxyl groups, leading to the enhanced reactivity in formaldehyde oxidation. A Pd/Al 2 O 3 nanocatalyst was pretreated at 750 °C in air, Ar or H 2 O/Ar, respectively. The effect of these different pretreatments on the active species and reactivity of Pd/Al 2 O 3 in formaldehyde oxidation at room temperature was investigated. The pretreatment was found to affect both the phase transformation of PdO to Pd metal and the Pd dispersion, leading to different catalytic performances. We found that the Pd/Al 2 O 3 nanocatalyst pretreated in both Ar and H 2 O/Ar show 60 % and 100 % formaldehyde conversion at 25 °C, respectively, while the catalyst pretreated in air is not active under the same condition. Pretreatments in both Ar and H 2 O/Ar were found to facilitate the formation of metallic Pd on Pd/Al 2 O 3 catalyst, confirmed by both experiments and calculation based on the function of the equilibrium oxygen pressure and temperature. We further found that the catalyst pretreated in H 2 O/Ar has higher Pd dispersion and more surface OH groups compared to that pretreated in Ar, leading to improved activity in formaldehyde oxidation.
研究领域:
催化化学
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环境科学
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DOI
高影响因子
Frontiers in Chemistry
·
2022
·
IF 5.545
Peng Shengpan,Ma Ziran,Ma Jing,Wang Hongyan,Chen Jingyun,Wei Hui,Li Yonglong,Ao Zhimin,Wang Baodong
Pd/Al2O3 catalysts modified by different chemical elements (Mg, Si, Ce, and Zr) were tested for methane (CH4) catalytic combustion, and PdO nanoparticles loaded on modified Al2O3 were systematically studied. These conditions assess the carrier effects of Pd/Al2O3 and acid strength influences on CH4 combustion. We observed carrier effects on activation energy through tuning Pd 3d binding energies (BEs) and on pre-exponential factors (A) through Pd dispersion and acidity on supports. When the BE of Pd 3d5/2 is 337.3 eV, PdO nanoparticles loaded on modified Al2O3 have excellent activity in cracking the C−H bond of CH4, which leads to the lowest activation energy (Ea), regardless of the size effect of the PdO nanoparticle. Furthermore, a theoretical construction that acid sites on catalysts promote the reversible elementary step (2Pd−OH ↔ Pd−O* + Pd* + H2O) right shifts improving the A dependency on the quantity of exposed Pd* and Pd−O*. As a result, Al2O3, as the carrier, not only modifies the electronic characteristics and size of supported PdO nanoparticles but also participates in the reaction process via acid sites on the surface of Al2O3.
研究领域:
催化化学
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环境科学
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DOI
高影响因子
GREEN CHEMISTRY
·
2020
·Vol. 22
·期 13
·4341-4349
·
IF 9.48
Yuxue Xiao,Qingwei Meng,Xiaoli Pan,Chao Zhang,Zaihui Fu,Changzhi Li
para-Xylene (PX) is a basic building block of polyethylene terephthalate, which is currently produced from petroleum resources. Developing a renewable route to PX is highly desirable to address both economic and environmental concerns. Several attempts used noble metal catalysts, e.g. Pd/Al2O3, to synthesize PX from biomass-derived 4-methyl-3-cyclohexene-1-carboxaldehyde (4-MCHCA), but suffered from a severe decarbonylation reaction, resulting in toluene as the main product. In this paper, we report an FeOx modification strategy to suppress the decarbonylation reaction on a Pd/Al2O3 catalyst, leading to a drastic shift in selectivity towards PX with a yield up to 81% via a cascade dehydroaromatization–hydrodeoxygenation (DHA–HDO) pathway. Characterization and control experiments revealed that the electron density of Pd sites decreased in an FeOx-modified Pd/Al2O3 catalyst compared to Pd/Al2O3, thus tuning the preferential adsorption mode of the substrate from η2-(C,O), the key transition state of the decarbonylation reaction, to the η1-(O) mode that favors the hydrodeoxygenation process. Notably, this designed catalyst is highly stable and is readily applicable in the selective synthesis of a broad range of desired aromatic chemicals via the same DHA–HDO pathway from cyclohex-3-enecarbaldehyde derivatives. Overall, this work develops a controllable catalyst modification strategy that tailors an efficient catalyst for petroleum-independent bio-PX synthesis.
研究领域:
催化化学
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可再生资源化学
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环境科学
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产品关联
DOI
高影响因子
Catalysis Science & Technology
·
2023
·Vol. 14
·期 2
·334-342
·
IF 5
Zhou Yang,Ru Wang,Hongji Liu,Zhou Chen,Xiaoli Hu,Limin Sun,Weikun Lai,Yunyun Dong,Weiping Fang,Xiaodong Yi
Selective hydrogenation is a significantly important catalytic process in many industrial processes, where Pd-based catalysts are the most commonly used. Herein, the surface properties of γ-Al2O3 were modified by the layered flower-like architectures of alkaline MgO using a simple hydrothermal method. Then, a series of Pd/Al2O3–MgO catalysts were prepared by an incipient wetness impregnation method for the selective hydrogenation of isoprene. The results showed that the Pd/Al2O3–0.12MgO catalyst exhibited superior catalytic performance with a high activity (93%) and high selectivity (99%) for the semi-hydrogenation products. Systematic studies have demonstrated that the support effect plays an important role in dispersing and stabilizing palladium particles. The reasons for the improved catalytic performance were attributed to the high dispersion of Pd nanoparticles, the changed electronic structure of Pd, and the strong interaction between Pd nanoparticles and supports. This work opens a simple route to regulate the electronic properties of active metal sites via support modification for selective hydrogenation reactions.
研究领域:
催化化学
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材料科学
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产品关联
DOI
高影响因子
Thermal Science and Engineering Progress
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2023
·
IF 4.8
Jing Yi,Pan Wang,Feixiang Li,Qi Chen,Lili Lei
Catalytic combustion of C 2 H 6 at equivalence ratios of 1.0 and 1.4 over non-thermal plasma (NTP) modified Pd/Al 2 O 3 was studied experimentally to examine the effect of O 2 and N 2 plasma on the catalyst activity and physico-chemical property. C 2 H 6 conversion, chemical product distribution and selectivity were taken into account to evaluate the performance of modified catalysts in C 2 H 6 oxidation at 200–500 ℃. The results showed that the plasma modification had suppressive effects on the activity of Pd/Al 2 O 3 . When compared to Pd/Al 2 O 3 , T 30 for the modified Pd/Al 2 O 3 were shifted to higher temperatures by approximately 30–50 ℃. For catalysts modified by plasma, significantly more CO was formed in the C 2 H 6 combustion at high temperature region. Moreover, the structure, morphology and chemical states of Pd/Al 2 O 3 after modification were thoroughly analyzed with the means of N 2 adsorption–desorption, XRD, XPS and SEM. The surface area of modified catalysts decreased, resulting in the activity degradation. The leaching of Pd species and transform of γ-Al 2 O 3 to θ-Al 2 O 3 were observed after the NTP treatment with highly energetic electrons. It should to be highlighted that the reduction of Pd 2+ to Pd 0 by NTP modification on the catalyst surface from XPS analysis. The NTP had the potential to reduce catalysts while employing oxidizing or inert gases.
研究领域:
催化化学
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环境科学
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材料科学
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DOI
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
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2022
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IF 4.326
Lian Duan,Chi Ma,Fengyan Lou,Jiabin Yin,Le Sang,Jisong Zhang
External mass transfer performance of micropacked bed reactors (μPBRs) with Pd/Al2O3/nickel foam catalysts is investigated by the hydrogenation of α-methylstyrene (AMS). The external mass transfer limitation region for AMS hydrogenation can be determined by means of the apparent activation energy and internal effectiveness factor. Parametric studies for external mass transfer are conducted by varying temperatures, operating pressures, liquid viscosities, gas and liquid superficial velocities, and pore diameters of foam packing. The external volumetric mass transfer coefficients [(ka)OV] of μPBRs with the Pd/Al2O3/nickel foam range from 0.06 to 0.71 s–1. An empirical correlation of (ka)OV is developed. Based on the gas–liquid–solid process analysis, the external mass transfer of μPBRs with the Pd/Al2O3/nickel foam is limited by liquid–solid mass transfer under the experimental conditions. Moreover, μPBRs with the Pd/Al2O3/nickel foam exhibit the best energy efficiency in comparison with that of other multiphase reactors.
研究领域:
化学工程
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催化
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反应器设计
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产品关联
DOI
高影响因子
FUEL PROCESSING TECHNOLOGY
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2023
·
IF 7.5
Jia Wang,Jianchun Jiang,Dongxian Li,Xianzhi Meng,Arthur J. Ragauskas
This study focuses on developing advanced oxygen-containing biofuels with high furan, cyclic ketone, and ethanol content from holocellulose and cellulosic wastes. To achieve this, we employed an integrated process that combined hydropyrolysis and vapor-phase hydrodeoxygenation using Pd/Al 2 O 3 as a catalyst. In the first stage, the non-catalytic hydropyrolysis of hemicellulose resulted in furfural and acetic acid fractions that were effectively converted into furans, cyclic ketones, and ethanol in the second-stage reactor over Pd/Al 2 O 3 under 0.3 MPa H 2 . We found that a hydropyrolysis temperature of 440 °C in the first stage reactor resulted in the highest yield of oxygen-containing biofuels (171.1 mg/g) with 89.2% hemicellulose conversion. However, increasing the hydrodeoxygenation temperature in the second stage reactor reduced the yield of oxygen-containing biofuels, and at 400 °C, excess deoxygenation led to hydrocarbon production. The Pd/Al 2 O 3 catalyst demonstrated high stability during the vapor-phase hydrodeoxygenation of primary furfural and acetic acid intermediates, with only 2.1% coke formation after three reaction cycles. This scalable process enables the conversion of various cellulosic wastes into advanced oxygen-containing biofuels, with considerable total yields. Our findings suggest that this integrated process holds great promise for converting biomass waste into advanced oxygen-containing biofuels.
研究领域:
生物化学工程
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可再生能源
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催化
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF CATALYSIS
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2016
·
IF 7.354
Xuelin Zou,Zebao Rui,Shiqi Song,Hongbing Ji
Poor durability and low Pd utilization efficiency are the main drawbacks of supported Pd catalysts for low-temperature methane combustion. Here, we present a facile way to stabilize the performance of Pd/Al 2 O 3 by introducing a spinel NiAl 2 O 4 interface as a promoter at no cost to the activity. The NiAl 2 O 4 interface is formed by impregnation of alumina supports in the nickel-containing solution, followed by high-temperature calcination. A series of 0.4 wt.% Pd/ x NiO/γ-Al 2 O 3 with NiO loading varying among 0.0, 0.5, 1.0, and 9.0 wt.% is investigated. The formation of a NiAl 2 O 4 interface promotes the distribution and crystallization of PdO, suppresses PdO particles aggregation and surface OH − species accumulation during the reaction, and finally leads to the excellent performance of Pd/0.5NiO/γ-Al 2 O 3 . Pd/0.5NiO/γ-Al 2 O 3 demonstrates higher Pd utilization efficiency than the state-of-the-art Pd-based catalysts and better stability than Pd/Al 2 O 3 . Such a spinel interface promotion strategy may bring new insight into the design of highly efficient Pd-based catalysts and their potential technological applications.
研究领域:
催化化学
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材料科学
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产品关联
DOI
高影响因子
INDUSTRIAL CROPS AND PRODUCTS
·
2023
·
IF 5.9
Tianqing Zhou,Chaojian Zhang,Lungang Chen,Yue Yao,Shuxiang Lu,Xiaoyuan Liao
The direct synthesis of 2,5-furandicarboxylic acid (FDCA) from readily renewable fructose, would provide a cost approach without separation of 5-hydroxymethylfurfural (HMF). The method would realize efficient and continuous production, reduced by-products, without cumbersome HMF separation process, and reduced production costs. In this work, we succeeded in converting fructose directly into FDCA over combined Amberlyst-15 and Pd/Al 2 O 3 in fixed bed reactor. We firstly time, compared One-bed two-catalysts (OBTC), and two-bed two-catalysts (TBTC) system. For the individual merits of the Amberlyst-15 and Pd/Al 2 O 3 , the catalytic performance of the combined beds is significantly improved compared with individual one. The high yields of FDCA (48 %) and fructose conversion (100 %) were obtained, respectively. Our one-step continuously method makes the FDCA production much more economical, energy-saved.
研究领域:
化学工程
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可再生资源利用
✓ 已验证
产品关联
DOI
高影响因子
CHINESE JOURNAL OF CHEMICAL ENGINEERING
·
2026
·
IF 3.5
Hongda Zhang,Jinyan Hu,Shuting Bao,Shichao Su,Weiyao Yang,Le Sang
Designing efficient catalysts and solvent system for the multiphase hydrogenation reaction is vital in continuous flow reactors. Herein, we prepare hydrophilic Pd/Al 2 O 3 and hydrophobic modified C 12 PA-Pd/Al 2 O 3 catalyst for nitrobenzene (NB) hydrogenation in micropacked bed reactors (μPBRs). By tuning the methanol-water volume ratio, reaction temperature, reaction pressure, liquid and gas superficial velocity, the NB conversion and aniline (AN) yield are optimized. The highest NB conversion of 97.1% and AN yield 95.6% are obtained in μPBRs with hydrophobic C 12 PA-Pd/Al 2 O 3 at the reaction temperature of 90 °C. The apparent kinetic model is developed in μPBRs with two types of catalysts, and activity energies of NB hydrogenation for Pd/Al 2 O 3 and C 12 PA-Pd/Al 2 O 3 are 7.944 kJ·mol -1 and 3.372 kJ·mol -1 , respectively. It indicates that the catalytic efficiency of C 12 PA-Pd/Al 2 O 3 is better than that of Pd/Al 2 O 3 in the methanol-water mixed solvent in μPBRs. The value of TOF for the hydrophobic modified C 12 PA-Pd/Al 2 O 3 catalyst is twice compared with the hydrophilic Pd/Al 2 O 3 catalyst. The value of STY for μPBRs is higher than that of stirred tank reactors (STRs) and fixed bed reactors (FBRs).
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产品关联
DOI
高影响因子
CHINESE JOURNAL OF CHEMICAL ENGINEERING
·
2023
·
IF 3.8
Qinqin Yuan,Jingyue Liang,Wei Li,Jinli Zhang,Cuili Guo
Anthraquinone hydrogenation to produce H 2 O 2 is an economically interesting reaction with great industrial importance. Here, we report a series of Pd/ x Al catalysts with different AlCl 3 contents by a conventional stepwise impregnation method. The optimal Pd/1.0Al catalyst exhibits a higher performance toward anthraquinone hydrogenation with 8.3 g·L −1 hydrogenation efficiency, 99.5% selectivity and good stability, obviously superior to that of Pd/Al 2 O 3 catalyst (5.2 g·L −1 and 97.2%). Detailed characterization demonstrates that AlCl 3 can be grafted on the γ-Al 2 O 3 support to obtain a modified support with abundant surface weak acid and Lewis acid, which can adsorb and activate anthraquinone. Meanwhile, its steric hindrance could isolate and disperse active metals to form more active sites. The synergies between metal sites and acid sites promotes the anthraquinone hydrogenation. Furthermore, the good stability after grafting AlCl 3 could attribute to the enhanced metal-support interaction inhibiting metal particles agglomeration and leaching.
研究领域:
催化化学
·
工业化学
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产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）