CRYSTENGCOMM
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2017
·Vol. 19
·期 44
·6588-6593
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IF 3.474
Yu Han,Wenxing Wang,Penglin Jiang,Yucong Yan,Hui Zhang,Deren Yang
Au nanorings are of particular interest in catalysis owing to their fascinating properties, however, it still remains a tremendous challenge to generate such hollow nanostructures with small size. Here, we report the synthesis of Au nanorings with an outer diameter of less than 20 nm by a seed-mediated approach with Pd nanoplates as seeds in the presence of Ag+ ions. The incorporation of Ag+ ions substantially slows down the reduction rate of the Au precursor through an underpotential deposition (UPD) process, leading to the formation of small Au nanoparticles. These small Au nanoparticles then coalesced into nanorings on small Pd nanoplates. The outer diameter of the Au nanorings is tuned by varying the size of the Pd nanoplates. The smallest Au nanorings are evaluated as catalysts towards the hydrogenation of 4-nitrophenol, showing substantially enhanced catalytic activity relative to the Au nanoparticles with the same size. This enhancement in the catalytic activity can be attributed to the unique structural features including the large specific surface areas, convenient accessibility of both interior and exterior surfaces for the reactants, and existence of highly active sites in the interior part.
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RSC Advances
·
2016
·Vol. 6
·期 110
·109023-109029
·
IF 3.289
Lijuan Lan,Fanglin Du,Chuanhai Xia
Carbon nanotubes (CNTs) supported Pd catalysts (1 wt% and 5 wt%) were prepared by a conventional impregnation method and tested in liquid-phase hydrodechlorination (HDC) of para-chlorophenol (p-CP) under mild conditions (313 K and atmospheric pressure) with H2. CNTs as a catalyst support offered better performance than activated carbon (AC). The conversion of p-CP reached 72% and 82% over 5 wt% Pd/AC and 5 wt% Pd/CNTs, respectively, within 30 min. When the content of Pd was reduced to 1 wt%, the conversion of p-CP over Pd/AC and Pd/CNTs was 55% and 83%, respectively. The mechanism of this phenomenon was studied through catalyst characterization (XRD, TEM, and BET). The abovementioned results indicated that the different activities of the catalysts over different supports mainly resulted from the porous structure of the supports and nanoparticle diameters of the active metal.
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ENERGY & FUELS
·
2024
·
IF 5.2
Congwen Duan,Jinhui Wu,Poqian Liang,Haimei Wang,Ting Qu,Yuchen Fan,Yaohua Su,Zhaohua Su,Lianxi Hu,Ying Wu
The hydrogen storage potential and cost-effectiveness of MgH2 have rendered it a desirable material for hydrogen storage. However, its application has been hindered by limitations in thermal stability and dehydrogenation kinetics. In this study, the carbon nanotube-Pd bifunctional catalyst was prepared by using hydrothermal and calcination technology, significantly improving the kinetics of Mg/MgH2 during hydrogen adsorption/desorption. The activation energy for the Mg@ CNTs-Pd was reduced to 42.73 kJ/mol, as determined by fitting the Avrami–Erofeev model with the Arrhenius equation. Additionally, the activation energy during dehydrogenation was found to be 73.98 kJ/mol based on the Johnson–Mehl–Avrami–Kolmogorov equation and the Arrhenius equation. It is worth noting that the dynamic enhancement persists even after 10 cycles. This groundbreaking research has paved the way for potential applications of MgH2 as a hydrogen storage material, providing it with broader development opportunities.
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AICHE JOURNAL
·
2024
·
IF 3.5
Zhongzhe Wei,Guanglu Dong,Long Zhao,Songtao Huang,Molin Xia,Wei Huang,Ming Jiang,Zhixiang Yang,Zihao Yao,Jianfeng Li,Jianguo Wang
Given that the retention of nitrogen readily renders active site poisoning, designing versatile catalysts characterized by notable selectivity and even resistance to poisoning for alkyne semi-hydrogenation under nitrogen-containing conditions is considerably challenging. In this article, oxanilide-decorated Pd/C (Pd/C-oxa) catalyst is facilely synthesized by leveraging impregnation-coordination, which exhibit remarkable performance in the semi-hydrogenation of nitrogen-containing alkynes, with ultrahigh turnover frequency (TOF) of 15,831 h −1 and selectivity of 97.2%. Strikingly, it still sustains TOF of 12,137 h −1 in a sulfur-containing system, demonstrating distinguished tolerance to sulfur. Comprehensive studies corroborate that oxanilide tunes the electron density of Pd by constructing metal–ligand electronic interactions, facilitating hydrogen activation. Simultaneously, the reaction microenvironment is optimized, which effectively promotes the desorption of nitrogen-containing olefins and attenuates the aggregation of nitrogen on the Pd surface. This strategy is universal and holds promising industrial applications, making it appropriate for use in commercial Pd/C catalysts as well.
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ACS Applied Materials & Interfaces
·
2024
·
IF 8.3
Xiaoxiao Wang,Yanmei Yang,Zhiqing Zhou,Yuling Zhong,Miaomiao Qin,Weiqing Wang,Weifeng Li,Bo Tang
5-hydroxymethylfurfural (HMF) is one of the most promising biomass-based chemicals that is used to produce many kinds of important compounds. Especially, the selective conversion of HMF to 5-hydroxymethyl-2-furancarboxylic acid (HMFCA), an important chemical feedstock, has high industrial significance but is technically challenging. In this study, we present a high-performance photocatalyst for selective oxidation of HMF to HMFCA. By integrating an ultrasmall amount of palladium (Pd) nanoclusters (1.12‰ in weight) on defective hexagonal boron nitride nanosheets (Pd/defective h-BN nanosheets (dh-BNs)), outstanding photocatalytic performance can be achieved, resulting in up to a 95% HMF conversion ratio with an 82% HMFCA selectivity. The performance is considerably higher than that of pristine dh-BNs and Pd on defect-free h-BNs. More importantly, this Pd/dh-BNs catalyst maintains a high catalytic activity after eight cycles, demonstrating robust catalytic stability. Density functional theory calculations indicate that Pd/dh-BNs can lower the energy barrier for HMF oxidation and facilitate the desorption of HMFCA, which contributes to the high selectivity catalytic performance. This study not only introduces a promising photocatalyst for sustainable chemical transformations but can also provide valuable insights into the design of advanced photocatalytic material for biorefinery applications.
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PubMed
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2024
·
IF 13.3
Fengshun Wu,Li Zeng,Lihua Zhu,Weizhen Wang,Chenghao Cao,Zhiqing Yang,Congxiao Shang,Hengqiang Ye,Zhengxiao Guo
Methanol and ethanol are liquid carriers of hydrogen, convenient and safe to store and transport, particularly of interest as mobile and marine fuels. These can be directly fed into a fuel cell to impart clean energy efficiently, only if their conversion can be cost-effectively catalyzed. In this regard, a cooperative catalyst is developed with atomic Pd species, in the form of single atoms and nanoclusters, dispersed over non-noble bi-metallic CoNi alloy nanoparticles, further supported on reduced graphene oxide (rG) (Pd@CoNi/rG). The catalyst demonstrates a methanol (ethanol) oxidation, MOR (EOR), mass activity (MA) of 1.730 (3.917) A mg −1 Pd (or Pt) , 4.55 (60.26) times greater than that of the commercial 20 wt% Pt/C and 8.65 (20.61) times higher than that of the commercial 20 wt% Pd/C, respectively. More importantly, the catalyst shows excellent stability, maintaining 83.7% (93.7%) of the initial performance after chronoamperometry (CA) for 50000 s in a solution of 1 M KOH + 1 M CH 3 OH (CH 3 CH 2 OH). It significantly out-performs other mono-/bi- metallic counterparts, e.g., Co/rG, Ni/rG, Pd/rG, CoNi/rG, Pd@Co/rG and Pd@Ni/rG, due to its unique cooperative nanostructure with synergistic effects of the different metal (Pd, Co and Ni)-related species.
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ChemCatChem
·
2017
·Vol. 10
·期 5
·1019-1026
·
IF 4.803
Qinhong Wei,Qingxiang Ma,Pingping Zuo,Huailin Fan,Shijie Qu,Wenzhong Shen
Graphical Hollow hydrogenation : A hollow CeO 2 spheres supported metallic Pd catalyst was prepared by employing a glucose hydrothermal method and impregnation method. The Pd/CeO 2 hollow sphere catalyst, which consisted of a hollow cavity and outer shell, presented a higher catalytic hydrogenation performance of styrene and nitrobenzene to produce ethylbenzene and aniline, better than that of the general CeO 2 -supported Pd catalyst. A hollow structured CeO 2 spheres supported metallic Pd catalyst (Pd/CeO 2 -H) was designed and prepared by a glucose hydrothermal method and impregnation method. The CeO 2 -H consisted of an inner hollow cavity and an outer shell on which a large number of mesopores were formed. The Pd/CeO 2 -H hollow sphere catalyst, which presented abundant surface oxygen vacancies, was investigated for catalytic hydrogenations of styrene and nitrobenzene to produce ethylbenzene and aniline. Activity tests indicated that the mesoporous Pd/CeO 2 -H hollow sphere catalyst exhibited striking catalytic activity, which was attributed to the spatial core–shell structure that provided more active sites and facilitated reactant diffusion as well as surface defects (oxygen vacancies), which were capable of transferring electrons to metallic Pd. All of these advances are beneficial to give a higher catalytic hydrogenation performance.
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CANADIAN JOURNAL OF CHEMICAL ENGINEERING
·
2024
·
IF 1.6
Yubo Yang,Yanxia Zheng,Lu Cai,Yuchao Li,Rui Xu,Cuncun Zuo,Haofei Huang,Ming Wang,Ruihui Dai,Liping Zhang,Yansong Zhao
Au-Pd alloy particles supported on TiO 2 were synthesized by the sol-immobilized method and their confirmation was achieved through transmission electron microscope (TEM) and energy dispersive spectrometer (EDS) mapping. The samples were subjected to oxidative esterification of methacrolein with methanol to methyl methacrylate (MMA). Notably, a remarkable enhancement of catalytic performance was found in the presence of Pd. Among the samples tested, the sample Au 0.25 Pd 0.75 /TiO 2 exhibited the highest catalytic performance. The interaction between Au and Pd demonstrated a synergistic effect, with Pd contributing to the stability of Au nanoparticles and strengthening the production of active oxygen species, which facilitated the efficient removal of hydrogen from intermediate hemiacetal. Furthermore, a probable reaction mechanism was proposed to explain these observations.
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INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
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2024
·
IF 8.1
Jiali Li,Yueru Jiang,Jianding Li,Yanling Hu,Yingying Shen,Huajun Zhao,Yongyang Zhu,Yun Zheng,Huaiyu Shao
Pd-based anode catalysts with superior activity are urgent for formic acid oxidation to further boost the direct formic acid fuel cells (DFAFCs) technologies. Herein, a strategy of ethylenediamine (EDA) modified Pd/C catalyst was developed by two main steps of EDA adsorbed on Vulcan XC-72 carbon by impregnation and Pd nanoparticles loaded on the freeze-dried C-EDA supports by liquid reduction method. The effects of sweep rates and concentrations of EDA on the formic acid electrooxidation were systematically studied. Results showed that the above parameter was optimized as the concentration of EDA of 0.1 mol L −1 . Pd nanoparticles with even distribution were fabricated and particle sizes were in the range of 3.5–4.2 nm. In addition, Pd particle size became smaller with the addition of EDA, suggesting that EDA could induce the generation of smaller Pd. Electrochemical measurements demonstrated that the electrocatalytic activity of Pd/C-0.22EDA (1021 mA mg −1 ) with optimized modification concentration was improved as a factor of 3.82 than that of Pd/C (267 mA mg −1 ). An enhanced stability (about 41 times higher than Pd/C) and faster charge-transfer kinetics of formic acid electrooxidation were observed for Pd/C-0.22EDA catalyst. CV and CA measurements showed that the most active catalyst was made of the smallest (3.5 nm) Pd nanoparticles for Pd/C-0.22EDA catalyst. The better electrocatalytic performances of Pd/C-0.22EDA might be ascribed to evenly dispersed Pd with relatively smaller particle size, electron regulation between Pd and amine group as well as stable Pd structure.
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INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2024
·
IF 3.8
Lian Duan,Hongda Zhang,Mengmeng Huang,Le Sang,Jisong Zhang
The coating materials of monolithic foam catalysts have a remarkable influence on the mass transfer and reaction process of packed bed reactors. However, the external mass transfer performance of micropacked bed reactors (μPBRs) based on the organic polymer-coated foam catalyst has not been investigated. This study explores the α-methylstyrene hydrogenation reaction and external mass transfer performance of μPBRs with a polydopamine (PDA)-coated foam catalyst. Pd/PDA/nickel foam has excellent α-methylstyrene hydrogenation activity and stability compared to Pd/Al2O3/nickel foam in μPBRs. The effect of pressure, gas and liquid superficial velocities, and pore size of foam packing on external mass transfer coefficient ((ka)OV) was investigated. The (ka)OV of the PDA-coated foam packing can reach 0.31–1.03 s–1, which shows a notable improvement over the Al2O3 coating. Furthermore, an empirical correlation equation for (ka)OV in μPBRs with PDA-coated foam packing is developed to provide a foundation for further design optimization and industrial applications.
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CHEMICAL ENGINEERING JOURNAL
·
2025
·
IF 13.2
Qing-Shan Niu,Yi-Ran Du,Xin-Peng Guo,Jing-Wen Sun,Si-Ping Pang,Bao-Hua Xu
The Pd-catalyzed N-debenzylation of hexabenzylhexaazaisowurtzitane (HBIW) to tetraacetyldibenzylhexaazaisowurtzitane (TADBIW) has provided high yields (up to 90.0 %, 12 h) in batch reactors, however, several phase transition stages during the catalytic process disable the development of a continuous flow system. In this work, we designed Pd-WO m bifunctional catalysts (Pd-WO m /MO n ) for such a transformation under three-phase reaction conditions with high efficiency. Remarkably, TADBIW was obtained with a high yield of 82.5 % upon reacting for 6 h at 40 °C on Pd-WO m (5.0)/CeO 2 (Pd: 1.33 mol%). Experimental studies combined with theoretical analysis reveal the HBIW-to-TADBIW conversion is a stepwise hydrogenolysis-acetyldebenzylation process, wherein the initial hydrogenolysis of Ac 2 O turn over the catalysis. Importantly, the presence of highly dispersed WO m domains with proper size not only facilitates hydrogen spillover from Pd site to the adsorpted Ac 2 O but also accelerates the subsequent dissociation of *Ac 2 O(H), enabling reduction of the overall energy barrier for debenzylation.
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Chemical Engineering and Processing-Process Intensification
·
2025
·
IF 3.9
Shichao Su,Yaqiao Tian,Huifeng Li,Weiyao Yang,Hongda Zhang,Feng Liu,Le Sang
The micropacked bed reactor (μPBR) with monolithic catalyst hydrogenation technology has received widespread attention due to its high efficiency, continuous operation, and safety. In this study, the Pd/PDA/foam catalyst was prepared via impregnation method and vanillin (VL) hydrogenation was investigated in green water solution based on the μPBRs. The effect of operating temperature, pressure, the number of foam catalyst block, VL concentration, liquid and H 2 flow rate on VL conversion and VA yield was discussed. The highest conversion of VL was 99.4% and product yield of vanillyl alcohol (VA) reached 84.9% with 2.8 MPa, 120°C, 22 blocks of Pd/PDA/Ni foam catalyst, H 2 flow rate of 10 mL·min −1 and liquid flow rate of 0.1 mL·min −1 , and short reaction time (0.106 h) in μPBRs. The kinetic of hydrogenation VL to VA was established. The reaction rate constant and activation energy in μPBRs were from 0.63 to 1.39 min −1 and 16.94 kJ·mol −1 . The STY of VA in μPBRs was 0.0824 kg·L −1 ·h −1 ·g −1 , which was bigger than that of batch hydrogenation devices.
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