RSC Advances
·
2019
·Vol. 9
·期 59
·34581-34588
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IF 3.049
Li Wang,Yue Zhang,Qingqing Ma,Zhiyong Pan,Baoning Zong
Organosilane-functionalized mesoporous silica SBA-15 was prepared by the co-condensation method and then applied as a support of Pd catalysts for hydrogenation of 2-alkyl-anthraquinone (AQ, alkyl = ethyl, tert-butyl and amyl). The as-prepared Pd catalysts were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, thermogravimetric analysis, N2 adsorption–desorption, zeta potential, water contact angles measurement and transmission electron microscopy. By extending the pre-hydrolysis time of the silica source, the content of functional groups in the catalysts slightly increases. However, there is an initial increase in zeta potential and water contact angles up to a maximum at 2 h, followed by a decrease as the pre-hydrolysis time was further prolonged. The hydrophobicity created by organic functionalization has positive effects on AQ hydrogenation. The catalyst with the highest hydrophobicity exhibits the highest catalytic activity, with increments of 33.3%, 60.0% and 150.0% for hydrogenation of ethyl-, tert-butyl- and amyl-anthraquinone compared with the unfunctionalized one.
研究领域:
化学工程
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催化科学
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DOI
PubMed
高影响因子
Catalysis Science & Technology
·
2021
·Vol. 11
·期 10
·3609-3618
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IF 6.119
Palle Ramana Murthy,Jing-Cai Zhang,Wei-Zhen Li
Pd-Based catalysts are efficient for methane combustion but impractical at high temperatures due to the sintering effect. Herein, we report a thermally stable Pd/SBA-15 catalyst that was prepared by using the sol-immobilization (SI) method, instead of the conventional incipient wetness impregnation (IWI) method. Pd nanoparticles retain the small size of ∼5 nm in the channels of SBA-15 in Pd/SBA-15-SI even after aging at 800 °C in air for 3 days, while those in the Pd/SBA-15-IWI samples aggregate into particles larger than 10 nm over the surface. The thermally stable Pd/SBA-15-SI indeed displays excellent catalytic activity for methane combustion at low temperatures with T50 at ∼300 °C and T90 at ∼350 °C and high stability during cyclic operations, which are much superior to those of the Pd/SBA-15-IWI catalysts. Interestingly, hydrothermal treatment of the Pd/SBA-15-SI catalysts leads to partial re-dispersion of Pd to form smaller particles of ∼1.6 nm, while the catalytic activity decreases a bit. Steam in the reactant mixture has a negative effect on the catalytic activity of Pd/SBA-15-SI catalysts, presumably due to the competitive adsorption of H2O to O2/CH4. Significantly, the size of Pd nanoparticles is essential to the catalytic performance and those having sizes of ∼5 nm are the most active. Finally, the catalytic activity of the catalysts in the presence of CO2 was studied. This work might be helpful in designing stable metal catalysts using porous materials for reactions under harsh conditions.
研究领域:
催化化学
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材料科学
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环境科学
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DOI
高影响因子
MICROPOROUS AND MESOPOROUS MATERIALS
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2020
·
IF 4.551
Yue Zhang,Li Wang,Nan Wang,Guohua Gao,Zhiyong Pan,Baoning Zong
Monodispersed mesoporous SBA-15 silica was synthesized by adding n -decane to conventional synthesis recipe. Pd catalysts for 2-alkyl-anthraquinone hydrogenation were then prepared on the as-synthesized SBA-15 and characterized by scanning and transmission electron micrographs, X-ray diffraction, XPS spectroscopy and N 2 adsorption-desorption. At the molar ratio of n -decane to P123 (C10/P123) ranging between 120 and 240, monodispersed SBA-15, together with the shortened length of pore channels, expanded size of mesopores and decreased proportion of micropores could be obtained. The Pd catalyst on SBA-15 synthesized with 240 in C10/P123 exhibited the superior catalytic performance. The initial hydrogenation rate of 2-ethyl-, tert-butyl- and amyl-anthraquinone increases by approximately 300%, 183% and 150% compared with that on SBA-15 synthesized using a recipe without n -decane, with the selectivity to active anthraquinone of >99%.
研究领域:
化学工程
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材料科学
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催化
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DOI
高影响因子
JOURNAL OF ANALYTICAL AND APPLIED PYROLYSIS
·
2016
·
IF 3.652
Qiang Lu,Zhi-bo Zhang,Xiao-ning Ye,Wen-tao Li,Bin Hu,Chang-qing Dong,Yong-ping Yang
A new technique was proposed to selectively produce 4-ethyl guaiacol (4-EG), a valuable phenolic compound, via low-temperature catalytic fast pyrolysis of softwood biomass using the Pd/SBA-15 catalyst. Pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) experiments were performed to compare 4-EG production from three biomass materials with different lignin types (pine wood, poplar wood and bagasse) and two catalytic patterns (in-situ and ex-situ). Further experiments were performed to reveal 4-EG formation affected by the pyrolysis temperature, catalyst-to-biomass ratio and Pd content of the Pd/SBA-15 catalyst. The results indicated that 4-EG could be selectively produced from pine wood by the in-situ catalytic pattern. 4-EG was a very minor pyrolytic product in the non-catalytic process, while it could be selectively produced in the catalytic process, via the decomposition and hydrogenation of lignin. Our results suggested that several holocellulose-derived pyrolytic products could serve as the hydrogen-donors (H-donors) for the formation of 4-EG, without any extra H-donors. The highest 4-EG yield of 18.44 mg/g from pine wood was obtained at the temperature of 350 °C and catalyst-to-biomass ratio of 2, and the corresponding peak area% (calculated by GC/MS) was 38.34%.
研究领域:
能源与燃料化学
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生物质转化技术
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DOI
高影响因子
TRANSACTIONS OF TIANJIN UNIVERSITY
·
2019
·Vol. 25
·期 6
·595-602
·
IF 0
Wang Nan,Ma Qingqing,Yuan Enxian,Wang Li
SBA-15 silica was synthesized by adding normal paraffin and alkyl benzene as swelling agents and using a low-temperature gelation procedure. Pd was then impregnated on SBA-15, yielding a catalyst. Characterizations of the catalyst by X-ray diffraction, N 2 adsorption/desorption, scanning electron microscopy, transmission electron micrographs, X-ray photoelectron spectroscopy, in situ FTIR, and a hydrogenation test of 2-ethyl-anthraquinone reveal that the addition of C 6 ‒C 9 normal paraffin and 1,3,5-triisopropylbenzene could enlarge the pore diameter without a significant loss of ordered structure. Moreover, the length of SBA-15 pore channels decreased significantly. However, the sizes of Pd particles increase as the pore diameter is enlarged. The largest pore size (13.6 nm) and short length of pore channels (ca. 0.35 μm) are achieved by adding n-hexane. As a result, this catalyst exhibits the highest hydrogenation activity with an approximately 100% improvement, compared with a conventionally synthesized catalyst in the absence of a swelling agent.
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Molecular Catalysis
·
2021
·
IF 5.062
Yue Zhang,Zhiyong Pan,Nan Wang,Li Wang
Silica SBA-15 without removal of template P123 was calcined in an inert atmosphere and the carbon-modified SBA-15 thus obtained was used as the support of Pd catalyst for the hydrogenation of 2-ethylanthraquinone (EAQ). The effects of extraction times of P123 in SBA-15 with water prior to inert calcination and calcination temperature on the structure and catalytic performance of Pd catalyst were studied. The results of elemental analysis, X-ray diffraction, X-ray photoelectron spectroscopy, inductively coupled plasma, Fourier transform infrared spectroscopy, Raman spectra, water contact angle measurement, N 2 adsorption-desorption, transmission electron microscopy and energy dispersive X-ray mapping showed that carbon content of catalysts varied in the range of 3.4 % and 1.1 % with increasing extraction times from 0 to 6 due to the decrease in the residual amount of P123 in uncalcined SBA-15. With rising calcination temperature, the occurrence state of carbon in catalysts was converted from amorphism into graphite. The Pd catalyst supported on SBA-15 extracted for 3 times and calcined at 650 °C had 2.0 % carbon, and exhibited the highest activity (0.37 molH 2 ·gPd −1 ·min −1 ) and selectivity (98.9 %). This is due to the presence of appropriate amount of carbon, which provided a relatively high hydrophobicity without significantly reducing the specific surface area and pore size of SBA-15 support. The high hydrophobicity benefits the adsorption of EAQ from the working solution to the surface of catalyst.
研究领域:
催化化学
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材料科学
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DOI
高影响因子
JOURNAL OF PHYSICS AND CHEMISTRY OF SOLIDS
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2019
·
IF 2.752
Xiao Jiang,Qing-Da An,Zuo-Yi Xia,Shang-Ru Zhai,L. Zhong-Cheng,Kai Wang
In this study, N-doped platelet-like metal-loaded Zr/SBA-15 was synthesized and employed for reducing 4-nitrophenol to remove this contaminant from water. Dopamine hydrochloride was used as a novel CN source for the modification of ZrSBA-15. The N doping process occurred readily at a low temperature due to the polymerization of dopamine, which could save energy and simplify the experimental fabrication of catalysts. In addition, polydopamine can immobilize Pd ions in a facile manner and the trapped Pd ions are reduced to Pd nanoparticles due to the reducibility of the polydopamine polymer. The utilization of dopamine allows the catalyst to be obtained in a facile and cost-effective synthetic process, while the production of the CN layer as well as the reduction and immobilization of the Pd ions can occur simultaneously. Characterization of the product showed that the catalyst had a platelet-like structure after decoration with elemental Zr, which enhanced the catalytic reaction compared with the natural fiber-like SBA-15. The optimal Pd loading capacity was determined as ~3.0 wt% and the materials obtained could reduce 4-nitrophenol to 4-aminophenol within 120 s with a conversion ratio above 90%.
研究领域:
催化材料
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环境科学
·
化学工程
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产品关联
DOI
高影响因子
JOURNAL OF ANALYTICAL AND APPLIED PYROLYSIS
·
2015
·
IF 3.564
Zhi-bo Zhang,Qiang Lu,Xiao-ning Ye,Wen-tao Li,Ying Zhang,Chang-qing Dong
A new technique was proposed to selectively produce 4-ethyl phenol (4-EP) from low-temperature catalytic fast pyrolysis of certain herbaceous biomass, while 4-vinyl phenol (4-VP) could be selectively produced from non-catalytic fast pyrolysis process. In this study, Pd/SBA-15 catalysts were prepared, and pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) technique was applied for both ex situ and in situ catalytic fast pyrolysis of bagasse . The results indicated the 4-EP could be selectively produced from both catalytic methods. During the ex situ catalytic pyrolysis process, the bagasse would decompose to form 4-VP which was then hydrogenated by the Pd/SBA-15 catalyst to be 4-EP. During the in situ catalytic pyrolysis process, the Pd/SBA-15 catalyst would catalyze the decomposition and hydrogenation of bagasse to directly produce 4-EP. Certain pyrolytic products would serve as the hydrogen-donors (H-donor) for the formation of 4-EP. The selectivity of the 4-EP from the ex situ catalytic process was a little better than that form the in situ catalytic process. The highest 4-EP yield from ex situ catalytic pyrolysis of bagasse was around 2.0 wt%, obtained at the pyrolysis temperature of 350 °C and catalyst-to-biomass ratio of 1.5.
研究领域:
能源与环境科学
·
化学工程
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DOI
高影响因子
ChemCatChem
·
2019
·Vol. 11
·期 20
·5098-5107
·
IF 4.495
Ning Xiang,Yaqin Hou,Xiaojin Han,Yulin Li,Yaoping Guo,Yongjin Liu,Zhanggen Huang
Room temperature HCHO catalytic oxidation over inert support loaded Pd catalysts remains a significant challenge. Herein, a series of alkali Na (1–4 wt.%) modified 1Pd/SBA-15 catalysts were prepared by a co-impregnation method and used for HCHO catalytic oxidation at room temperature. Results showed that alkali Na significantly improved the HCHO oxidation performance of 1Pd/SBA-15 and the optimal Na loading was 2 wt.%. BET, XRD, STEM, XPS, H 2 -TPR, O 2 -TPD and in situ DRIFTS were performed to reveal the promotion role of alkali Na. As a consequence, alkali Na addition could stabilize well dispersed Pd particles which then facilitated the O 2 activation and accelerated the decomposition of formate intermediates species, thus a superior HCHO catalytic oxidation performance was obtained. This study first clearly illustrated the promotion mechanism of alkali Na without the implication of active support and provides an efficient and facile way to achieve high dispersion of Pd particles on inert support and tremendously expands the selected range of supports for room temperature HCHO catalytic oxidation. Graphical Alkali promoted : A series of Na alkali-promoted 1Pd/SBA15 catalysts were prepared by a co-impregnation method and tested for HCHO catalytic oxidation at room temperature. Addition of alkali Na stabilized well-dispersed Pd particles which facilitated O 2 activation and accelerated formate species decomposition rate, leading to superior HCHO catalytic oxidation performance of 2Na-1Pd/SBA-15.
研究领域:
催化化学
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环境科学
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材料化学
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表面科学
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大气污染控制
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DOI
高影响因子
RSC Advances
·
2017
·Vol. 7
·期 6
·3443-3449
·
IF 3.108
Ying Duan,Min Zheng,Dongmi Li,Dongsheng Deng,Cuicui Wu,Yanliang Yang
The Pd/SBA-15 catalyst was synthesised through the reduction of PdCl2 by the surface-bonded vinyl group on vinyl-functionalized SBA-15, which was prepared via co-polymerization. XRD and XPS characterization confirmed the successful reduction of Pd(II) to Pd(0). Pd/SBA-15 showed a narrow palladium particle-size distribution of about 5–6 nm in the TEM image. The Pd/SBA-15 catalyst was effective for the hydrogenation of aromatic nitro compounds with zero-order kinetics, and the TOF for the hydrogenation of nitrobenzene was 1124 h−1 at 313 K and 1 atm H2. A steric effect was observed for the substituted nitroarenes.
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
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