APPLIED ORGANOMETALLIC CHEMISTRY
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2012
·Vol. 26
·期 9
·478-482
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IF 2.061
Wenyi Chu,Xinmin Li,Yanjun Hou,Hua Wang,Hongyu Li,Xiaobin Yuan,Zhizhong Sun
Pd/C-catalyzed Suzuki–Miyaura cross-coupling between aryl bromides and arylboronic acids in 50% methanol aqueous solution proceeded smoothly in the presence of 18-crown-6. Various aryl bromides bearing electron-withdrawing groups and electron-donating groups coupled with arylboronic acid in high yields. In addition, the catalyst could be recycled five times without loss of activity. Copyright © 2012 John Wiley & Sons, Ltd.
研究领域:
有机化学
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催化化学
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DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
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2022
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IF 16.744
Xingjie Guo,Ge Gao,Javier Remón,Ya Ma,Zhicheng Jiang,Bi Shi,Daniel C.W. Tsang
Food waste worldwide has been threatening the environment and resulting in high carbon emissions. Although anaerobic fermentation is a potential solution transforming food waste into valuable chemicals, a large amount of the fermentation residue remains as solid waste. For closing the circular economy loop for food waste valorization, we proposed a thermo-chemical activation of a fermentation residue produced from a mixture of food waste and sludge to prepare a nitrogen-enriched, advanced carbon material. This could be used as a support to synthesize Pd/C, Pt/C and Au/C catalysts for the aqueous-phase hydrogenation of vanillin to vanillyl alcohol at mild reaction conditions. The produced alcohol increased sixfold the commercial value of the original aldehyde. The catalytic performance (based on the vanillin conversion and vanillyl alcohol yield) followed the order of Pd/C > Pt/C > Au/C. The Pd/C catalyst showed an excellent catalytic activity (>99% vanillin conversion and > 99% vanillyl alcohol selectivity) at optimized reaction conditions (i.e., 30 °C and 0.7 MPa H 2 for 90 min, with 2 mmol vanillin/10 mg catalyst), along with high reusability and stability (up to four consecutive runs). These catalytic features outperformed those of a commercial Pd/C catalyst owing to: (i) high reduction degree and stabilization of the Pd particles on the carbon support, which accommodated a higher proportion of pyridinic than pyrrolic nitrogen, and (ii) rapid adsorption of the aldehyde group on the catalyst combined with rapid desorption of the newly formed hydroxymethyl group. This exceptional catalytic behavior was corroborated by efficient hydrogenation of other lignin-derived aromatic aldehydes, including p-hydroxybenzaldehyde and syringaldehyde, to their respective alcohols. Our results can bring a novel use for food waste in catalysis and represent a sustainable and efficient conversion of biomass into value-added chemicals and advanced materials.
研究领域:
催化
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可持续化学
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废物管理
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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
Environmental Science-Nano
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2020
·Vol. 7
·期 7
·2117-2129
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IF 7.683
Zhiqiang Zhang,Jinsuo Lu,Bing Zhang,Wenxin Shi,Yuan Guo,Fuyi Cui
Catalytic denitrification over Pd-based catalysts under mild conditions has received significant attention as an emerging technology. However, the Pd particle size effect has been much less systematically investigated. Herein, carbon-supported Pd nanoparticles (NPs) with particle sizes ranging from 2.1 to 22.1 nm were synthesized and characterized using high-resolution transmission electron microscopy (HR-TEM), X-ray diffraction (XRD), CO-chemisorption, and X-ray photoelectron spectroscopy (XPS). Catalytic nitrite reduction experiments were conducted in a semi-batch reactor at room temperature. The results showed that the highest mass catalytic activity of 603.6 mg gPd−1 min−1 was obtained at the Pd size of 2.7 nm. The turnover frequency (TOF) and the N2 selectivity increased gradually with the increasing Pd NP size. Considering both the mass catalytic activity and N2 selectivity, the Pd catalyst with a size of approximately 5 nm had a better comprehensive performance. Mechanism studies showed that the enhanced TOF of larger Pd NPs could be ascribed to the formation of more β-hydride, which has a higher reducing activity than α-hydride. Compared with the terraces, the edges and corners of Pd NPs are the major active sites where ammonia is generated, most likely because of their low-coordination and electron-deficient properties. This indicated that the NO2− catalytic reduction is a size sensitive reaction in terms of both activity and selectivity, and may provide new insight into tailoring Pd NP size of Pd-based catalysts to improve catalytic activity and selectivity for nitrate and nitrite reduction in water.
研究领域:
环境科学
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催化化学
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产品关联
DOI
高影响因子
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
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2022
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IF 7.139
Xiaoying Qi,Xiang Gong,Na Ye,Zhao Jiang,Tao Fang
Direct methanol and formic acid fuel cells attracted extensive attention with high specific energy and low operating temperature. The efficient electrocatalyst was one of the important factors to limit their commercial applications. Here, the nitrides-modified Pd/C catalysts (Pd–NbN/C, Pd–Mo 2 N/C, Pd-VN/C and Pd-BN/C) were prepared using sodium citrate as a reducing agent in ethylene glycol solution. The mass activities followed the trend of Pd–NbN/C > Pd–Mo 2 N/C > Pd-VN/C > Pd-BN/C > Pd/C, where Pd–NbN/C exhibited the highest mass activity (4052.19 A g Pd −1 ) for MOR, 19.2 times that of the commercial Pd/C (210.53 A g Pd −1 ). Electrochemical measurements (LSV, Tafel, EIS, CA) indicated that the addition of nitrides increased the charge-transfer kinetics, reaction rate and CO tolerance of catalysts for MOR in alkaline media . The rate-determining step was CO ads oxidation process . Combined the structural analysis (HRTEM, XRD , XPS , ICP) with electrochemical results, the enhanced catalytic performance was ascribed to that higher ECSAs and the charge transfer between Pd and nitrides, leading to the negative shift of the d-band center towards the Fermi level . The linear correlations were found for the d-band center VS the mass activities and the onset potential of CO oxidation VS the d-band center, indicating that the activity and anti-CO poisoning ability could be enhanced by controlling the d-band structure of catalysts for MOR. Furthermore, the higher mass activity for FAOR in acidic media suggested that nitrides-modified Pd/C may be the promising bi-functional materials.
研究领域:
电化学
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催化材料科学
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产品关联
DOI
高影响因子
ChemCatChem
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2025
·
IF 3.9
Jingrong Li,Tingting Xiao,Xinluona Su,Qihang Gong,Peikai Luo,Jian Li,Haiyang Cheng,Fengyu Zhao
Graphical The evolution of the geometric structure and electronic states of Pd species was revealed for Pd/C catalysts in catalyzing the dehydrogenation of 12H-NECZ. The oxidized Pd δ+ species was reduced to Pd 0 species with finely-dispersed on the surface of support to generate H 2 with a high efficiency of 98.3%. The dehydrogenation of liquid organic hydrogen carriers is of significant potential for hydrogen energy applications. We successfully synthesized a highly efficient and stable Pd/C catalyst featuring ultrasmall (2.22 nm) and stable Pd nanoparticles via the deposition–precipitation method for the dehydrogenation of dodecahydro- N -ethylcarbazole. Interestingly, the Pd structure evolves during the reaction, with the Pd 2+ species on Pd/C catalyst re-dispersing into uniformly small-sized Pd 0 nanoparticle under reaction conditions. The conventional thermal treatment of calcination–reduction typically results in larger Pd particles due to the stronger metal-support interaction. Kinetic studies revealed the oxidation state of Pd 2+ species (Pd(OH) 2 , PdO) is more active for the dehydrogenation reaction compared to the metallic state Pd 0 species. The in situ structure evolution induced ultrasmall Pd nanoparticles (2.22 nm) with a constant Pd 0 /Pd 2+ ratio, achieving a high efficiency (98.3%) of H 2 release from 12H-NECZ dehydrogenation at 180 °C. This work provides a simple method for preparing highly dispersed Pd/C catalyst with stable ultrasmall Pd particles, offering valuable insights to researchers in the field of supported metal catalysts.
研究领域:
催化化学
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材料科学
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能源化学
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DOI
高影响因子
Journal of CO2 Utilization
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2018
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IF 5.503
Yu-Nong Li,Xiao-Fang Liu,Liang-Nian He
The oxazolidinone as one kind of annular CO 2 derivatives has been hydrogenated by a new catalytic system Pd/C-TMGPEG 150 Me (polyethylene glycol-functionalized 1,1,3,3-tetramethyl guanidine), affording two valuable products i.e. formic acid and the corresponding secondary alkyl-(2-arylethyl)amines in the high yields of 89% and 98%, respectively. This hydrogenation can be carried out smoothly under relatively mild conditions of 60 °C, 4 MPa of H 2 with a liquid/solid carbon source (oxazolidinone) instead of high pressure CO 2 . The notable results can be successfully obtained even at room temperature under atmospheric H 2 pressure. This one stone two bird strategy is applicable to series of 5-aryl-2-oxazolidinones and opens up a novel way of synthesizing linear secondary alkyl-(2-arylethyl)amines without the selectivity issues, and validates a potential alternative approach for indirect conversion of CO 2 to energy-related products formic acid, as oxazolidinones can be readily obtained from hydrogenation of CO 2 .
研究领域:
化学
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催化科学
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绿色化学
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产品关联
DOI
高影响因子
Arabian Journal of Chemistry
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2022
·
IF 6.212
Donghai Jiang,Yongyong Shi,Liming Zhou,Jun Ma,Hongyan Pan,Qian Lin
Nitrogen-doped porous carbon is potential support for directly synthesizing H 2 O 2 from H 2 and O 2 . Here, density functional theory (DFT) was used to study the effect of N -doped porous carbon on H 2 O 2 directly synthesized. The theoretical calculation results showed that N -doped improved H 2 O 2 productivity and H 2 conversion by increasing the dispersion of Pd nanoparticles and the Pd 0 /Pd 2+ ratio. However, N -doped decreased H 2 O 2 selectivity by reducing oxygen's dissociation energies. The experimental results showed that adjusting the pore structure of N -doped porous carbon could improve the adverse effects of N -doping for H 2 O 2 selectivity. The H 2 O 2 productivity and selectivity of Pd/C catalyst with a macropore-mesoporous-microporous hierarchical porous structure were up to 328.4 mol H2O2 ·kg cat -1 ·h −1 and 71.9 %, respectively, at ambient pressure. The macropore structure enhances the transfer and diffusion performance of the catalyst and effectively inhibits the effect of N -doping on O O bond dissociation, which improves H 2 O 2 productivity and selectivity. This research provides a possible solution for designing a high-performance Pd/C catalyst to directly synthesize H 2 O 2 from H 2 and O 2 at ambient pressure.
研究领域:
化学工程
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催化科学
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产品关联
DOI
高影响因子
BIOMASS & BIOENERGY
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2024
·
IF 5.8
Zhenjing Jiang,Wuyu Wang,Xuelai Zhao,Xinghua Zhang,Qi Zhang,Longlong Ma
Production of jet fuel is not only promising but challenging in the field of biomass utilization. Here we proposed a novel route to produce highly branched alkanes with ultra-low freezing point using n-butyraldehyde as feedstock by self-aldol condensation and subsequent hydrodeoxygenation (HDO). The catalyst characterization revealed that the MgO-SiO 2 catalyst played an acid-base synergetic effect role in the self-aldol condensation of n-butyraldehyde using n-butanol as solvent, which obtained C8 oxygenate and C12 oxygenate with yield of 69.3 % and 26.8 % respectively. The medium Brønsted base site of the catalyst captured α-H to promote the formation of enolate from n-butyraldehyde, and the Lewis acid sites promoted the dehydration of intermediate products. DFT simulation showed that n-butanol activated α-C in enolate in aldol condensation, and deactivated the oxygen atoms in enolate by hydrogen bonds to inhibit side reactions. Finally, the obtained condensation products were subjected to HDO reaction over the 5 wt% Pd/C and HZSM-5 catalysts, obtaining the highly branched alkanes with an ultra-low freezing point of -120.7 °C for C8 alkane and -78.7 °C for C12 alkane suitable for bio-jet fuels.
研究领域:
生物质利用
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催化化学
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能源科学
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产品关联
DOI
高影响因子
ELECTROCHIMICA ACTA
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2022
·
IF 7.336
Lu Li,Jiahao Gu,Yaqi Ye,Jun Guo,Jie Zhao,Guifu Zou
Efficient and stable electrocatalysts are essential for generating continuous and clean hydrogen energy through electrochemical water splitting. Palladium (Pd) has been widely used in various catalytic reactions due to its unique electronic structures and chemical properties. Herein, we reported a facile synthesis strategy to homogeneously embed Pd nanoparticles in nitrogen-doped porous carbon fibers (Pd-PCNFs) through three successive processes of pre-oxidation, carbonization, and etching. The porous carbon fiber not only acts as a support matrix for highly dispersed Pd nanoparticles to avoid sintering in the high temperature process, but also provides efficient ion penetration and mass transport during the hydrogen evolution reaction (HER) process. More importantly, Raman and X-ray photoelectron spectroscopy (XPS) characterization confirmed the effective synergy between Pd nanoparticles and N-doped porous carbon fibers, which will help enhance the intrinsic electrocatalytic activity of Pd nanoparticles. Consequently, Pd-PCNFs-800 obtained by annealing at 800 °C exhibit significantly enhanced and stable electrocatalytic activity with an onset potential of 0 mV (0.5 M H 2 SO 4 ) and 40 mV (1 M KOH). It is noteworthy that the catalytic activity of Pd-PCNFs-800 is close to or better than commercial 10% Pd/C in different electrolytes. Impressively, in alkaline media, the activity of Pd-PCNFs-800 is even superior to commercial Pt/C at large current densities (>48.6 mA cm −2 ). This work provides a novel perspective to design and enrich the applications of Pd-based catalysts supported on carbon substrates.
研究领域:
材料科学
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电化学
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催化
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能源材料
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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）