APPLIED ORGANOMETALLIC CHEMISTRY
·
2018
·Vol. 33
·期 2
·e4708
·
IF 3.581
Mingliang Ma,Yuying Yang,Dili Liao,Ping Lyu,Jinwei Zhang,Jianli Liang,Lizhi Zhang
A strategy has been developed for the synthesis, characterization and catalysis of magnetic Fe 3 O 4 /P(GMA-EGDMA)-NH 2 /HPG-COOH-Pd core-shell structure supported catalyst. The P(GMA-EGDMA) polymer layer was coated on the surface of hollow magnetic Fe 3 O 4 microspheres through the effect of KH570. The core-shell magnetic Fe 3 O 4 /P(GMA-EGDMA) modified by -NH 2 could be grafted with HPG. Then, the hyperbranched glycidyl (HPG) with terminal -OH were modified by -COOH and adsorbed Pd nanoparticles. The hyperbranched polymer layer not only protected the Fe 3 O 4 magnetic core from acid–base substrate corrosion, but also provided a number of functional groups as binding sites for Pd nanoparticles. The prepared catalyst was characterized by UV–vis, TEM, SEM, FTIR, TGA, ICP-OES, BET, XRD, DLS and VSM. The catalytic tests showed that the magnetic Fe 3 O 4 /P(GMA-EGDMA)-NH 2 /HPG-COOH-Pd catalyst had excellent catalytic performance and retained 86% catalytic efficiency after 8 consecutive cycles.
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GREEN CHEMISTRY
·
2019
·Vol. 21
·期 18
·5046-5052
·
IF 9.405
Ziwei Guo,Feng Zhou,Hao Wang,Xiaohao Liu,Guangyue Xu,Ying Zhang,Yao Fu
A novel and green catalytic system based on a Pd stabilized CuZnAl catalyst was designed for one-pot conversion of natural oil components to the corresponding alcohols or long-chain linear and branched alkanes with high selectivity and atom economy. When methyl decanoate was used as the model compound, a nearly full yield of n-decanol was obtained at 200 °C and 2 MPa H2 within 8 h. 100% decane was produced when acidic HZSM-5 was introduced under the same reaction conditions, and the selectivity of n-decane and i-decane could be tuned by temperature. Cu species were verified as the active sites for lipid conversion, while a small amount of Pd could stabilize the catalyst to avoid Cu leaching. The reaction pathway involved hydrogenation, where methyl decanoate can be equivalently converted to methanol and decanol or decane, and no extra CO2 or CO from decarboxylation or decarbonylation was detected. This system increases the sustainability and economy of natural oil conversion to valuable liquid fuel and chemicals.
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SENSORS AND ACTUATORS B-CHEMICAL
·
2019
·
IF 6.393
Xuechao Xu,Linjie Wang,Xiaobo Zou,Shuwen Wu,Jianming Pan,Xin Li,Xiangheng Niu
Given that hypertoxic arsenite (As 3+ ) poses a serious threat to the environment and global health, developing high-performance, low-cost and easy-to-use approaches to specifically monitor As 3+ in environmental matrices turns to be of great importance. In the present work, we reported a novel colorimetric assay of As 3+ based on the reassembly-induced oxidase-like activity inhibition of dithiothreitol-capped Pd nanoparticles (Pd-DTT). The Pd-DTT nanozyme exhibits good oxidase-like catalytic activity to trigger the oxidation of colorless 3,3′,5,5′-tetramethylbenzidine (TMB) in the presence of O 2 , forming a blue product TMBox. When As 3+ exists, it can chelate the sulfydryl groups in DTT more strongly, leading to a reassembly of Pd-DTT. Compared with the original nanozyme, the reassembled one has much less oxidase-like activity, resulting in the significantly suppressed TMB reaction. Based on this principle, highly sensitive detection of As 3+ was achieved, providing a wide linear range from 33 ng L −1 to 333.3 μg L −1 and an ultralow detection limit of 35 ng L −1 . With the help of EDTA as a chelating agent, the method could also offer excellent selectivity for the determination of As 3+ against other metal ions. Besides, our colorimetric assay was employed to accurately measure the analyte in spiked drinking and river water, revealing its great promise in environmental analysis application.
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GREEN CHEMISTRY
·
2019
·Vol. 21
·期 15
·4143-4151
·
IF 9.405
Shanjun Mao,Bowen Zhao,Zhe Wang,Yutong Gong,Guofeng Lü,Xiao Ma,Lili Yu,Yong Wang
Semi-hydrogenation of alkynols to alkenols with Pd-based catalysts is of great significance in fine chemical industries. Industrial Lindlar catalysts, employing Pb to modify the Pd nanoparticles for higher selectivity toward alkenols, however, generally suffer from both a severe activity decrease and environment pollution caused by using heavy metal Pb and additives. Therefore, how to overcome the selectivity–activity paradox remains a great challenge in industry. Here, we report a controllable strategy for the synthesis of semi-hydrogenation catalysts, which successfully improves the catalytic performance through selectively poisoning the edge and corner sites of Pd nanoparticles. When the integrity of the crystal face is reserved, both higher activity (∼1340 h−1) and selectivity (∼95% at 99% conversion) are achieved in the semi-hydrogenation of 2-methyl-3-butyn-2-ol (MBY) in ethanol, an industrially important intermediate product for the synthesis of vitamin E, without adding any toxic additives. What's more, the yield could exceed 98% at 99% conversion under no solvent and organic adsorbate conditions, which had never been achieved before. This work provides a different perspective to design and develop high performance catalysts for semi-hydrogenation of alkenols or even substituted alkynes.
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RSC Advances
·
2019
·Vol. 9
·期 17
·9620-9628
·
IF 3.049
Qiuli Wei,Tongjun Liu,Yuanyuan Wang,Liyi Dai
Herein, three-dimensional (3D) nitrogen-doped graphene with large surface areas and abundant porous structures was prepared by a hydrothermal synthesis method, which served as a novel support to enhance the catalytic properties of noble metal catalysts for the solvent-free selective oxidation of benzyl alcohol. The as-prepared samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, Fourier transform infrared (FTIR) spectroscopy, and Brunauer–Emmett–Teller (BET) method. The results clearly showed that the introduced N-containing group prevented the aggregation of graphene sheets and provided more structural defects to maximize the number of exposed active sites. The three-dimensional structure can provide a unique porous structure and large specific surface area. Moreover, the three-dimensional structure makes the recycling and reuse of the catalyst easier. The combination of these properties results in the reduction of the average particle size of metal palladium to 3.2 nm; this significantly increases the catalytic activity of the catalyst. The three-dimensional N-doped graphene aerogel-supported Pd nanoparticle (3D Pd/NRGO) composites exhibit excellent catalytic activity for the solvent-free selective oxidation of benzyl alcohol to benzaldehyde by molecular oxygen at 90 °C for 3 hours under atmospheric pressure, resulting in a 72.2% conversion of benzyl alcohol with 94.5% selectivity for benzaldehyde. In addition, the catalytic efficiency shows no obvious loss even after six repeated cycles. Thus, 3D Pd/NRGO can be used as an efficient, easily separable, recyclable, and stable catalyst for the solvent-free selective oxidation of benzyl alcohol under relatively mild conditions.
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ACS Catalysis
·
2018
·
IF 11.384
Qi Xue,Juan Bai,Congcong Han,Pei Chen,Jia-Xing Jiang,Yu Chen
Optimizing the shape, structure, and interface of noble metal bimetallic nanostructures significantly improves their catalytic properties. Recently, Au@Pd core–shell bimetallic nanostructures have attracted considerable interest for fuel cell applications. Regrettably, most of the research mainly focuses on the morphological and structural control whereas interfacial control is neglected. In this work, polyethylenimine (PEI) functionalized Au nanowires@Pd core–shell bimetallic nanohybrids (Au-NWs@Pd@PEI) are synthesized by a chemical reduction method using Au nanowires (Au-NWs) as seeds in the presence of PEI and demonstrate their application toward oxygen reduction reaction (ORR) in an alkaline solution. Electrochemical results display that Au-NWs@Pd@PEI with optimal component shows enhanced ORR activity, selectivity, and durability compared to Pt/C electrocatalyst. Physical characterizations demonstrate that the electronic property of Pd shell mainly is affected by PEI polymer rather than Au-NWs core. Relative to PEI functionalized Pd nanowires without Au core, ORR activity enhancement of Au-NWs@Pd@PEI is exclusively ascribed to the surface strain effect. Meanwhile, loose-packed PEI polymer on the Pd surface can work as barrier nanosieves to exclusively prevent the access of methanol to Pd sites, which imparts Au-NWs@Pd@PEI with enhanced methanol tolerance toward ORR in an alkaline solution.
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JOURNAL OF CATALYSIS
·
2018
·
IF 6.759
Yujie Song,Hao Wang,Shijing Liang,Yan Yu,Liuyi Li,Ling Wu
The photoalkylation of nitroarenes with benzyl alcohols in one pot at room temperature and 1 atm N 2 was achieved over the Pd/H 1.07 Ti 1.73 O 4 ·H 2 O nanosheets. The sample shows efficient photocatalytic activity with high conversion of nitrobenzene (99%) and selectivity of secondary amine (85%). This flexible photocatalytic system is also applicable to other nitroarenes with high efficiency. Results of in situ FTIR, DRS, and in situ ESR revealed that the benzyl alcohol and nitrobenzene molecules can bind with the surface Lewis and Brønsted acid sites in the catalyst via the H O⋯Ti and NO 2 ⋯H O Ti species. The formation of surface coordination species results in not only the activation of reactant molecules via surface electron transfer, but also the expanded visible light absorption of the catalyst. Moreover, in situ ESR suggested that the surface coordination can also facilitate the formation of oxygen vacancies in catalysts, which can greatly promote the exposure of Lewis sites and enhance the activation of reactant molecules. Finally, a possible hydrogen transfer strategy over the sample is proposed on a molecular level.
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CHEMOSPHERE
·
2018
·
IF 4.427
Huafeng Li,Jin Wang,Rui Wang,Kaibo Huang,Wanying Luo,Xueqin Tao,Zhi Dang,Hua Yin,Chuling Guo,Guining Lu
Polybrominated diphenyl ethers (PBDEs) belong to a class of persistent organic pollutants (POPs), with potential toxicity to the liver, reproductive system, and development of mammals. The highly toxic and concentrated congener, 2,2′,4,4′-tetrabromodiphenyl ether (BDE-47), was chosen to investigate debromination mechanisms by the two synthetic iron-based bimetals (Pd/Fe 0 and Cu/Fe 0 ) in two protic solvents (water and ethanol). SEM, XPS, and BET analyses showed that the synthetic bimetals Pd/Fe 0 and Cu/Fe 0 were spherical with diameters of about 100 nm and loaded with ∼1% (wt%) of Pd and Cu, respectively. GC-MS was used for the analysis of degradation products and the chromatograms showed that both Pd/Fe 0 and Cu/Fe 0 bimetals had effective reducing properties in water solvent. In ethanol solvent, debromination of BDE-47 by Pd/Fe 0 showed a similar high activity, but BDE-47 could be hardly degraded by Cu/Fe 0 . The dominant debromination products of BDE-47 by Pd/Fe 0 and Cu/Fe 0 were ortho -substituted and para -substituted BDEs, respectively. Active H-atomic transfer was found to play a key role in the debromination of BDE-47 by Pd/Fe 0 in both, water and ethanol, with a preference for para -debromination along with the formation of dibenzo-p-furan (DF) as the by-product, mainly in water. In contrast, electron transfer with a preference for ortho -debromination was found to play a predominant role for Cu/Fe 0 system in water. More importance should be provided to active H-atomic transfer for its high efficiency. In-depth study on the mechanism of formation of by-product DF would be significant for its higher toxicity, possibility of accumulation and migration in the environment.
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ACS Applied Nano Materials
·
2018
·
IF 0
Guohong Ren,Yajun Liu,Weigang Wang,Mingqian Wang,Zhicheng Zhang,Ying Liang,Shishan Wu,Jian Shen
Exploitation of highly active catalysts for alcohol electrooxidation is urgent for direct alcohol fuel cells (DAFCs). In this research, a facile and mild synthetic approach is utilized to control and tailor the morphology of the three-dimensional (3D) urchin-like Pd@PtNi nanostructures (NSs), and the formation mechanism of the as-prepared nanostructures is expounded in detail. The Pd@PtNi NSs exhibit outstanding electrochemical properties and remarkable durability toward both methanol and ethanol oxidation reaction (MOR and EOR) in alkaline solution. The electrochemically active surface area (ECSA) of the Pd@PtNi NSs is 59.5 m2 g–1, and their mass activities for MOR and EOR are 1614.3 and 1502.3 mA mg–1, respectively, which are much higher than those of their ternary or binary alloy counterparts as well as commercial Pt black catalysts. Moreover, it still retains high current densities after catalyzing 10 000 s, while the current densities of other nanocatalysts reduce to nearly zero. The outstanding electrochemical activities and durability are owing to the specific 3D urchin-like nanostructures providing enormous active sites for catalytic reaction and the synergy effects between Pt, Pd, and Ni atoms. The 3D urchin-like Pd@PtNi NSs will enrich the electrocatalysts for DAFCs.
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ACS Applied Materials & Interfaces
·
2019
·
IF 8.456
Geng Chen,Yi Wang,Hanqin Weng,Zhihao Wu,Kebao He,Peng Zhang,Zifang Guo,Mingzhang Lin
The recovery of precious metals like palladium (Pd) from secondary resources has enormous economic benefits and is in favor of resource reuse. In this work, we prepared a high efficiency pyridine-functionalized reduced graphene oxide (rGO) adsorbent for selective separation of Pd(II) from simulated electronic waste leachate, by one-pot γ-ray radiation-induced simultaneous grafting polymerization (RIGP) of 4-vinylpyridine (4VP) from graphene oxide (GO) and reduction of GO. The poly(4-vinylpyridine)-grafted reduced graphene oxide (rGO-g-P4VP) exhibits fast adsorption kinetics and high maximum adsorption capacity. The adsorption capacity is 105 mg g–1 in the first minute and reaches equilibrium within 120 min. The adsorption process follows the Langmuir model, from which the maximum adsorption capacity of Pd(II) is estimated to be 177 mg g–1. We also proved that the adsorption mechanism of Pd(II) on rGO-g-P4VP involves both ion exchange and coordination adsorption by XPS analysis. Most importantly, the loss of oxygen-containing groups due to reduction of GO not only facilitates the separation of adsorbent from aqueous solution but also reduces the electrostatic repulsion toward Pd(II)Cl42– in hydrochloric acid solution, leading to a higher adsorption selectivity of Pd(II) over some common metal cations in electronic waste including Fe(III), Cu(II), and Al(III) compared with poly(4-vinylpyridine)-grafted graphene oxide (GO-g-P4VP) prepared by atom transfer radical polymerization. Other precious metals like Pt(IV) and Au(III) can also be recovered easily and selectively by rGO-g-P4VP. This work demonstrates that rGO-g-P4VP prepared by the facile RIGP is a promising adsorbent for recovery of precious metals from secondary resources like electronic waste leachate.
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ACS Omega
·
2019
·
IF 2.584
Ran Wang,Qingqing Liu,Tifeng Jiao,Jinghong Li,Yandi Rao,Jingjing Su,Zhenhua Bai,Qiuming Peng
In recent years, people pay more attention to environmental pollution and the treatment of sewage has become the focus of recent research. Palladium nanoparticles have good catalytic properties but are easy to agglomerate. Therefore, we used the electrospinning technology to prepare a uniform composite nanofiber film based on polyacrylic acid (PAA) and polyvinyl alcohol (PVA), which demonstrated that they are good carriers of palladium nanoparticles to make the nanoparticles well dispersed. Furthermore, carbon nanotubes (CNTs) were added to increase the specific surface area of the composite nanofiber film and improve its mechanical properties. The successfully synthesized PAA/PVA/CNT-COOH@palladium nanoparticle (PdNP) composite fiber films were characterized by scanning electron microscopy, transmission electron microscopy, and thermogravimetry analysis. p-Nitrophenol and 2-nitroaniline were utilized as typical pollutants to further evaluate the catalytic performance of PAA/PVA/CNT-COOH@PdNP composite fiber films. The PAA/PVA/CNT-COOH@PdNP composite fiber films exhibited enhanced catalytic performance and could be reused for eight consecutive cycles. This work provided new clues for the preparation and application of composite electrospun film materials.
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ACS Sustainable Chemistry & Engineering
·
2019
·
IF 6.97
Jiahui Kang,Jiahui Chen,Jiali Sheng,Jinqi Xie,Xian-Zhu Fu,Rong Sun,Ching-Ping Wong
To meet the ever-growing clean energy technology, developing effective catalysts for the oxygen evolution reaction (OER) is imperative for boosting the efficiency of electrochemical water splitting. This work reports Pd nanoparticle-interspersed nickel cobalt hydroxide carbonate nanothorn-coated copper hydroxide nanotube arrays grown on a copper foam (CH@NCHC NT-Pd/CF) as highly efficient OER electrocatalytic electrodes. The nanothorns and open-structured nanotubes have large surface areas and plenty of active sites. Particularly, the interfacial interaction between Pd nanoparticles and NCHC nanothorns causes charge transfer and redistribution, which are highly beneficial to promoting OER. The unique 3D integrated construction also can accelerate the electron and mass transfer and improve structural stability. Owing to the above merits, CH@NCHC NT-Pd/CF shows excellent OER electrocatalytic activity and stability in alkaline solution, delivering a current density of 100 mA cm–2 at a low overpotential of 207 mV and small voltage fluctuation in 12 h of electrolysis.
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