ACS Catalysis
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2016
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IF 9.307
Da Lei,Kai Yu,Meng-Ru Li,Yuling Wang,Qi Wang,Tong Liu,Pengkun Liu,Lan-Lan Lou,Guichang Wang,Shuangxi Liu
Single-crystalline Pd nanocrystals enclosed by {111} or {100} facets with controllable sizes were synthesized and originally employed as catalysts in the aerobic oxidation of 5-hydroxymethyl-2-furfural (HMF). The experimental results indicated that the particle size and exposed facet of Pd nanocrystals could obviously influence their catalytic performance. The size-dependent effect of Pd nanocrystals in this reaction could only be derived from the different Pd dispersions. Therefore, the facet effect of Pd nanocrystals was first investigated in this work through experimental and theoretical approaches. It was found that Pd-NOs enclosed by {111} facets were more efficient than Pd-NCs enclosed by {100} facets for the aerobic oxidation of HMF, especially for the oxidation step from 5-hydroxymethyl-2-furancarboxylic acid (HMFCA) toward 5-formyl-2-furancarboxylic acid (FFCA). The TOF value of Pd-NOs(6 nm) was 2.6 times as high as that of Pd-NCs(7 nm) and 5.2 times higher than that of commercial Pd/C catalyst for HMF oxidation. Through density functional theory (DFT) calculations, the notably enhanced catalytic performance of Pd-NOs could be mainly attributed to the lower energy barrier in the alcohol oxidation step (from HMFCA to FFCA) and higher selectivity for O2 hydrogenation to produce peroxide.
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Small
·
2015
·Vol. 11
·期 36
·4745-4752
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IF 8.368
Yi Li,Wenxing Wang,Kaiyang Xia,Wenjun Zhang,Yingying Jiang,Yuewu Zeng,Hui Zhang,Chuanhong Jin,Ze Zhang,Deren Yang
Despite a few reports on the synthesis of ultrathin 2D nanosheets made of noble metals, it still remains a tremendous challenge to generate their ultrathin hollowed nanostructures, which are of particular interest in highly active catalysis due to their unique structural features. Here, the synthesis of ultrathin 2D Pd nanorings is reported with a hollow interior by selective epitaxial growth of Pd atoms on the periphery of the as-preformed Pd nanosheets in combination with oxidative etching. This approach can be extended to fabricate Pd-based bimetallic ultrathin nanorings such as Pd–Pt. The Pd nanorings exhibit substantially enhanced activity toward the hydrogenation of p -nitrophenol, which is 2.2 and 33.4 times higher than that of the Pd nanosheets and commercial Pd black, respectively. Significantly, the Pd nanorings are highly stable with only less than 11% loss in activity compared to 45.7% loss of the Pd nanosheets and 72.2% loss of the Pd black after ten cycles.
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INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
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2014
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IF 2.235
Miao Liang,Rongxin Su,Wei Qi,Yi Zhang,Renliang Huang,Yanjun Yu,Libing Wang,Zhimin He
Efficient immobilization of catalytic active metal nanoparticles into porous supporting materials is of important scientific interest in practice. We report on the fabrication of novel bionanocomposites, comprising a three-dimensional porous eggshell membrane (ESM) bioscaffold decorated with catalytic active metal (Pt, Pd) nanoparticles, to reduce highly toxic Cr(VI). Procyanidin (Pro), a natural plant polyphenol with abundant phenolic hydroxyls, was first covalently grafted on the ESM fiber surface to provide stable binding sites for chelating metal precursors. Highly dispersed Pt and Pd nanoparticles with small size were facilely generated and stably immobilized onto the surface of ESM followed by NaBH4 reduction. These metal nanoparticle-incorporating ESM composites were active heterogeneous catalysts for the reduction of toxic Cr(VI) to Cr(III) by employing formic acid as the reducing agent. Notably, it is easy to recover and recycle the catalysts, revealing the good stabilization of procyanidin-grafted ESM for nanoparticles.
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Catalysis Science & Technology
·
2015
·Vol. 6
·期 6
·1913-1920
·
IF 5.426
Renfeng Nie,Hezhan Jiang,Xinhuan Lu,Dan Zhou,Qinghua Xia
N-doped active carbon (N-AC) has been synthesized via heat treatment of a mixture consisting of dicyandiamide as the nitrogen source and commercial active carbon as the precursor. This material is especially adapted for anchoring ultrafine Pd nanoparticles by a very clean strategy using H2 as the reductant. The physicochemical properties of materials were investigated by powder X-ray diffraction (XRD), Raman spectroscopy, Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). The results reveal that the variation of the treatment temperature can assist the tuning of the content of N and the dispersion of Pd on xN-AC, by which Pd nanoparticles with a narrow size distribution centered at around 1.8 nm can be obtained. These robust catalysts show very high catalytic activity for the aromatic ring hydrogenation of acidic substrates, such as electron-deficient benzoic acid or electron-rich phenol, under mild conditions in aqueous media. Excellent catalytic results (9.2 times higher activity in comparison to non-doped catalyst for benzoic acid hydrogenation), high stability and easy recyclability of the catalyst were achieved. The strong interaction between the pyridinic nitrogen group and Pd species will lower the reducibility of the Pd species and result in the formation of relatively electron-deficient and ultra-small sized Pd clusters, thus leading to high hydrogenation activity.
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BIORESOURCE TECHNOLOGY
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2014
·
IF 5.039
Riyang Shu,Jinxing Long,Zhengqiu Yuan,Qi Zhang,Tiejun Wang,Chenguang Wang,Longlong Ma
An efficient lignin depolymerization process with highly controllable product distribution was presented using metal chloride (MCl x ) cooperated with Pd/C. The catalytic performances of MCl x were investigated. The effect of reaction conditions on the lignin depolymerization and products distribution were also studied. Results showed that more than 35.4% yield of phenolic monomer including 7.8% phenols and 1.1% guaiacols could be obtained under optimized condition. And the product distribution can be efficiently controlled by the modification of the metal cation through different pathway of Lewis acid catalysis and coordination catalysis. Furthermore, the Pd/C catalyst showed an excellent recyclability, where no significant loss of the catalytic activity was exhibited after 3 runs. Moreover, the product control mechanism was proposed.
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ACS Applied Materials & Interfaces
·
2014
·
IF 5.9
Long Zhang,Lianhuan Du,Xiang Yu,Shaozao Tan,Xiang Cai,Peihua Yang,Yu Gu,Wenjie Mai
Electron–hole recombination is one of the major factors limiting the efficiency of ZnO-based photocatalysts. In this work, a 2-fold enhancement strategy was employed to suppress electron–hole recombination and boost photocatalytic efficiency. First, significantly enhanced photocatalytic activity of ZnO by introducing graphene oxide (GO) was systematically investigated. Hybrid photocatalysts with different weight ratios of ZnO to GO (from 0.95:0.05 to 0.70:0.30) were synthesized and characterized. The results indicated that when the proportion ratio of ZnO to GO reached 0.85:0.15, the as-synthesized ZnO–GO nanocomposite exhibited the maximum photocatalytic efficiency on methylene blue with an apparent rate constant κapp almost 10 times faster than that of pure ZnO under UV illumination. GO was suggested to enhance the photocatalytic activity of ZnO because of its great capability in dye adsorption and charge separation. Second, Pd nanoparticles were introduced to decorate ZnO–GO to produce generally better photocatalyst ZnO–GO–Pd nanocomposites. The junction between Pd and ZnO was believed to also effectively separate the photogenerated charges due to the metal-semiconductor diode effect. These two systems of ZnO–GO and ZnO–GO–Pd nanocomposites are expected to have a broad range of applications in environmental conservation.
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JOURNAL OF ANALYTICAL AND APPLIED PYROLYSIS
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2015
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IF 3.564
Xiao-ning Ye,Qiang Lu,Wen-tao Li,Pan Gao,Bin Hu,Zhi-bo Zhang,Chang-qing Dong
A new technique was proposed to selectively produce nicotyrine, a valuable alkaloidal product, from catalytic fast pyrolysis of tobacco mixed with the Pd/C catalyst. Pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) experiments were performed to investigate the effects of pyrolysis temperature and catalyst-to-tobacco ratio on the selective nicotyrine production. The actual nicotyrine yields under different reaction conditions were quantitatively determined. Moreover, the catalytic activity of the Pd/C catalyst was compared with those of the activated carbon (AC), Ru/C and Pd/SBA-15 catalysts. The results indicated that during the catalytic fast pyrolysis process, the Pd/C catalyst possessed promising dehydrogenation capability to selectively convert the nicotine in tobacco into the nicotyrine, and it performed much better than the other three catalysts. The maximal nicotyrine yield reached as high as 2.80 wt%, obtained at the pyrolysis temperature of 400 °C and catalyst-to-tobacco ratio of 2.
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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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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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CHEMICAL ENGINEERING JOURNAL
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2024
·
IF 13.3
Zhichen Liu,Zongxuan Yang,Hongwei Zhang,Shidong Wang,Qunhong Liu,Zhengyu Zhao,Xiaojun Bao,Pei Yuan
Palladium-based catalysts have been intensively investigated for the hydrogenation of nitroarenes due to their high activity. However, it remains a challenge to achieve high selectivity when reducing or halo groups are present. Herein, we propose a facet engineering strategy to regulate the activity and selectivity of Pd/TiO 2 and a series of Pd/TiO 2 catalysts with adjustable proportions of (101) and (001) facet of TiO 2 were synthesized for the selective hydrogenation of nitroarenes. With increased percentage of (101) facet, better dispersed Pd species and more oxygen vacancies (O V ) can be generated on the Pd/TiO 2 catalyst, thereby providing increasing hydrogenation reaction centers with strongly adsorbed nitro groups. As a result, the Pd/TiO 2 with dominant (101) facet and 0.1 wt% of Pd loading (Pd/TiO 2 -c) delivers an outstanding conversion (100 %) of m-chloronitrobenzene, high selectivity (96.8 %) toward m-chloroaniline, and excellent reusability. In situ characterizations and density functional theory (DFT) simulation reveal that the Pd/TiO 2 -c exhibits much stronger adsorption toward nitro groups than chlorine group, while the catalyst with more (001) facet shows similar adsorption capability toward these two groups. Thereby, nitro group is more preferentially adsorbed and hydrogenated during the reaction on Pd/TiO 2 -c, which explains the excellent selectivity. Remarkably, Pd/TiO 2 -c can also realize excellent conversion (100 %) and selectivity (> 96 %) toward other functional nitroarenes containing −F, –OH, –CHO, –COCH 2 - groups. This work highlights the facet engineering of supports to tune the physicochemical properties of loaded active metal and the adsorption behavior of reactants, and provides an effective strategy for the further development of efficient Pd-based catalysts for selective nitroarenes hydrogenation.
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INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
·
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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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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