Molecular Catalysis
·
2020
·
IF 3.687
Ning Xiang,Xiaojin Han,Yarong Bai,Qiaoyan Li,Jianfeng Zheng,Yulin Li,Yaqin Hou,Zhanggen Huang
Supported noble metal catalysts have been widely utilized for HCHO catalytic oxidation. When the active components are fixed, the altering and regulation of the supports would have a huge effect on catalytic performance. Here, two types of Pd/γ-Al 2 O 3 catalysts with different support size (micro-γ-Al 2 O 3 and nano-γ-Al 2 O 3 , respectively) were fabricated and used for HCHO oxidation. Compared with the micro-sized counterpart, the Pd/nano-γ-Al 2 O 3 catalyst exhibited much superior HCHO oxidation performance which could totally oxidize 160 ppm of HCHO into harmless CO 2 under a WHSV of 100,000 mL g cat −1 h −1 at room temperature. Multiple characterizations including XRD, BET, TEM, CO chemisorption, FT-IR, O 2 -TPD, XPS and in situ DRIFTS were implemented to study the effect of γ-Al 2 O 3 support size on physicochemical properties of Pd/γ-Al 2 O 3 catalysts and elucidate the structure-activity relationship. The results revealed that large specific surface area, rich surface OH groups as well as high curvature of nano-γ-Al 2 O 3 not only facilitated HCHO adsorption, but also stabilized highly dispersed Pd species which then promoted the activation of oxygen and boosted formate species decomposition, and consequently leading to the enhanced HCHO oxidation performance of Pd/nano-γ-Al 2 O 3 . This work deepens the comprehension of support size-dependent activity of Pd/γ-Al 2 O 3 catalysts for HCHO oxidation and provides an alternative method to prepare high-performance Pd catalysts for HCHO oxidation.
研究领域:
催化化学
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
NEW JOURNAL OF CHEMISTRY
·
2017
·Vol. 41
·期 21
·13036-13042
·
IF 3.269
Fenfen Lu,Yan Xu,Xia Jiang,Yang Liu,Jiale Huang,Daohua Sun
Low temperature 1,3-butadiene hydrogenation over biosynthesized Pd/γ-Al2O3 catalysts annealed under different atmospheres (H2 and air) was compared in a fixed bed reactor, and the catalysts were prepared using a facile sol-immobilization method. The structural properties of the Pd/γ-Al2O3 catalysts in relation to their activities in 1,3-butadiene hydrogenation were investigated by X-ray photoelectron spectroscopy, X-ray diffraction, hydrogen temperature-programmed reduction, thermogravimetry, transmission electron microscopy, CO chemisorption measurement techniques and Fourier transform infrared spectroscopy. The results of characterization revealed that the calcination atmosphere (H2 and air) exhibited a remarkable impact on the chemical state of Pd species and catalytic activity, and the coexistence of the metallic state and oxidation state of Pd was a key factor for higher catalytic activity and butene selectivity, while the catalyst with the existence of the metallic state only (H2–Pd/γ-Al2O3) showed lower butene selectivity, and the catalyst with the oxidation state alone (air–Pd/γ-Al2O3) hardly showed any activity in 1,3-butadiene hydrogenation. Therefore, the chemical state of Pd played an important role in the 1,3-butadiene hydrogenation reaction.
研究领域:
催化化学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
APPLIED CATALYSIS A-GENERAL
·
2022
·
IF 5.723
Xiang Li,Xiaomin Ren,Maodi Wang,Qihua Yang
Direct hydrogenation of nitrobenzene (NB) to dicyclohexylamine (DCHA) is a green but challenging process due to the competition of cross-coupling reaction (to DCHA) and hydrogenation reaction (to byproduct). Herein, we report that the cross-coupling reaction to desired DCHA is greatly enhanced by tuning the acidity of supported Pd catalysts. It was found that Pd NPs loading on commercial γ-Al 2 O 3 (γ-Al 2 O 3-Com ) with moderate acidity were more selective than those on neutral SBA-15 or strongly acidic γ-Al 2 O 3 nanorods . The presence of acid site could promote the coupling reaction. By analyzing the correlation between hydrogenation activity and DCHA selectivity, it was found that the matched rate of hydrogenation and cross-coupling is the key factor to achieve high selectivity. This study may open a new avenue for the hydrogenation of nitroarenes to DCHA by regulating the acidity of supports and the reaction conditions.
研究领域:
化学工程
·
催化
·
有机化学
✓ 已验证
DOI
高影响因子
CHINESE JOURNAL OF CHEMICAL ENGINEERING
·
2019
·
IF 1.911
Weiquan Cai,Junlin Zhuo,Jimin Fang,Zhichao Yang
A series of nanorod-like porous Pd/γ-Al 2 O 3 catalysts with controllable textural properties and enhanced catalytic performance in 2-ethyl-9,10-anthraquinone (eAQ) hydrogenation for H 2 O 2 preparation were successfully prepared via a facile sol–gel method using aluminum isopropoxide as aluminum precursor and eAQ as structure directing agent, sequential calcination and impregnation process with Na 2 PdCl 4 solution. The physicochemical properties of the catalysts obtained with different addition amounts of eAQ were comparatively characterized by XRD, TG–DSC, BET, TEM, CO-TPR, H 2 -TPR and H 2 –O 2 titration. The results show that addition of eAQ can not only effectively control the textural properties (surface area, pore volume and average pore size) of the catalysts, but also lower their reduction temperature of active metal. Importantly, the catalyst obtained with an addition amount of 4 wt% eAQ shows the highest hydrogenation efficiency of 10.28 g·L −1 , which is 37.3% higher than 7.49 g·L −1 of the catalyst obtained without eAQ.
研究领域:
催化
·
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF CATALYSIS
·
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
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
Molecular Catalysis
·
2023
·
IF 4.6
Yanzhao Gao,Xianglei Meng,Shiqi Huang,Hui Wu,Liantao Jiang,Yu Zhou,Yuting Song,Yanyan Diao
Gamma alumina is widely utilized for preparing the supported noble metal catalysts for the hydrogenation reaction. It is an effective strategy to improve the catalytic performance of catalysts via modifying gamma alumina with alkaline earth metal to regulate its surface acidity and electronic properties. Herein, Pd catalysts supported by Al 2 O 3 and Mg-modified Al 2 O 3 are synthesized via the wet impregnation method, and the effects of MgO doping on the structure, composition, and surface acidity of Pd/γ-Al 2 O 3 catalysts are investigated via X-ray diffraction patterns (XRD), Transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and Temperature programmed desorption (TPD). The results show that Pd/MgO-Al 2 O 3 –2 (γ-Al 2 O 3 modified with 2 wt% Mg) has more metallic state palladium and weak acid sites and exhibits the best catalytic performance for the hydrogenation of perfluoro-4-methyl-2-pentene (D1). Density functional theory (DFT) calculations on Pd/Al 2 O 3 and Pd/MgO-Al 2 O 3 –2 catalysts are also performed to further explore the mechanism of D1 hydrogenation. The studies for Gibbs free energy of the potential reaction steps and intermediates reveal a complex process to generate the target product C 6 F 12 H 2 , and the rate-determining-step is the addition of the first hydrogen on the second carbon of perfluoro-4-methyl-2-pentene molecule.
✓ 已验证
产品关联
DOI
高影响因子
ENERGY & FUELS
·
2021
·
IF 3.605
Beibei Feng,Yitong Zhai,Lidong Zhang
The combustion and catalytic combustion of ethanol (a typical bioalcohol) at atmospheric pressure and an equivalence ratio of ϕ = 3 were investigated in a flow reactor. Reactants, important intermediates, and products were detected and identified by gas chromatography–mass spectrometry. For ethanol combustion, the hydrogen abstraction reaction attacked by OH radicals is the initial pathway for ethanol consumption. Acetaldehyde is regarded as an important intermediate in ethanol combustion through kinetic analysis. However, catalytic combustion of ethanol over γ-Al2O3 is dominated by bimolecular and unimolecular dehydration reactions to produce diethyl ether and C2H4, while Pd/γ-Al2O3 can strongly oxidize ethanol to CO2 with a dramatic decrease in the decomposition temperature. To further understand the mechanism of catalytic combustion, pyrolysis and catalytic pyrolysis of ethanol were also explored. The product distribution in catalytic pyrolysis demonstrated weaker coke deposition over γ-Al2O3 in comparison to catalytic combustion. In addition, the deactivation of Pd/γ-Al2O3 at high temperatures was probably due to the increase in the concentration of oxygenated species to cover the active Pd site. The apparent activation energy was estimated by the Arrhenius equation to illustrate the difference in primary reaction channels. This work bridges the gap between combustion and catalytic combustion of ethanol, which is beneficial for the improvement of catalytic performance and control of pollutants by combining pyrolysis and combustion.
研究领域:
化学工程
·
环境科学
·
能源科学
✓ 已验证
产品关联
DOI
高影响因子
CATALYSIS TODAY
·
2022
·
IF 6.562
Peng Bai,Tao Zhou,Xiaohua Wang,Xiaofei Liu,Yi Wang,Yue Wang,Edgar Muhumuza,Yonghui Zhang,Pingping Wu
A series of γ-Al 2 O 3 supported gold-palladium (Au-Pd) alloy nanoparticles (NPs) catalysts were synthesized by a one-pot approach applying mercapto-propyl-trimethoxysilane (MPTMS) as an anchoring ligand. Homogeneously dispersed Au-Pd alloy NPs were observed on the prepared catalysts and their catalytic performance in benzyl alcohol partial oxidation was investigated. Results showed that the highest benzaldehyde yield was achieved on catalyst Au-Pd/7%MPTMS-γ-Al 2 O 3 with a benzaldehyde selectivity of 90%. By establishing the structure-performance relationship, the high activity of catalysts with MPTMS modification was attributed to the anchoring and dispersion effect of MPTMS on Au-Pd NPs, while the high benzaldehyde selectivity was due to the formation of more surface Lewis acid sites after introducing MPTMS, protecting the benzaldehyde from over-oxidation to byproducts.
研究领域:
催化化学
·
材料科学
✓ 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）