CHEMICAL ENGINEERING JOURNAL
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2018
·
IF 6.735
Shengdong Dai,Xitian Wu,Jinli Zhang,Yan Fu,Wei Li
Coenzyme A (CoA), as a cofactor of enzymes in bacteria, is involved in various reactions of intermediary metabolism owing to its thiol groups. Herein we develop a facile CoA-assisted approach for the green synthesis of nonspherical Pd nanoparticles (NPs) with grain boundaries, which potentially serve as the catalytic hot spots. As-prepared CoA-Pd nanocomposites were applied for the catalytic reduction of highly toxic chromium (VI) by using formic acid (FA) as the reductant with the highest reduction rate of 2.45 mmol mg −1 min −1 (50 °C), which is superior to recently reported homogenous and heterogeneous Pd-based catalysts. Through the characterizations by UV–vis, FTIR, TEM, XRD and XPS in combination with DFT calculations, CoA plays an essential role in regulating the growth of Pd NPs, resulting in the formation of nonspherical morphology at high [Na 2 PdCl 4 ]/[CoA]. The catalytic activity of CoA-Pd was also assessed for the hydrogenation reduction of p-nitrophenol and the degradation of trichloroethylene (TCE) in the presence of formic acid. This strategy expands eco-friendly synthetic techniques to design highly efficient nanocatalysts to meet the requirement of catalytic reduction of Cr(VI) and other types of FA-mediated hydrogenation reactions.
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高影响因子
ChemCatChem
·
2015
·Vol. 7
·期 16
·2485-2492
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IF 4.556
Guangyue Xu,Jianhua Guo,Ying Zhang,Yao Fu,Jinzhu Chen,Longlong Ma,Qingxiang Guo
Graphical Phosphate aids palladium: A highly reactive, selective, compatible, stable and low-cost catalytic system for selective hydrogenation of phenol to cyclohexanone is described, which consists of well-dispersed Pd nanoparticles anchored to the hydroxylapatite surface that supports the specificity through its basic sites. The production of pure cyclohexanone under mild conditions over catalysts with high reactivity, selectivity, compatibility, stability, and low cost is still a great challenge. Here we report a hydroxyapatite-bound palladium catalyst (Pd–HAP) to demonstrate its excellent performance on phenol hydrogenation to cyclohexanone. Based on catalyst characterization, the Pd nanoclusters (≈0.9 nm) are highly dispersed and bound to phosphate in HAP. Only basic active sites on HAP surface are detected. At 25 °C and ambient H 2 pressure in water, phenol can be 100 % converted into cyclohexanone with 100 % selectivity. This system shows a universal applicability to temperature, pH, solvent, low H 2 purity, and pressure. The catalyst reveals high stability to be recycled without deactivation or morphology change; and Pd nano-clusters barely aggregate even at 400 °C. During the reaction, HAP adsorbs phenol, and Pd nanoclusters activate and spillover H 2 . The mechanism is also investigated, proposed, and verified.
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PLoS One
·
2015
·Vol. 10
·期 7
·e0131450
·
IF 3.234
Hangjun Zhang,Xiaojun Jiang,Liping Lu,Wenfeng Xiao
Polychlorinated biphenyls (PCBs), a class of hazardous pollutants, are difficult to dissipate in the natural environment. In this study, a cyanobacterial strain Anabaena PD-1 showed good resistance against PCB congeners. Compared to a control group, chlorophyll a content decreased 3.7% and 11.7% when Anabaena PD-1 was exposed to 2 and 5 mg/L PCBs for 7 d. This cyanobacterial strain was capable of decomposing PCB congeners which was conclusively proved by determination of chloride ion concentrations in chlorine-free medium. After 7 d, the chloride ion concentrations in PCB-treated groups (1, 2, 5 mg/L) were 3.55, 3.05, and 2.25 mg/L, respectively. The genetic information of strain PD-1 was obtained through 16S rRNA sequencing analysis. The GenBank accession number of 16S rRNA of Anabaena PD-1 was KF201693.1. Phylogenetic tree analysis clearly indicated that Anabaena PD-1 belonged to the genus Anabaena . The degradation half-life of Aroclor 1254 by Anabaena PD-1 was 11.36 d; the total degradation rate for Aroclor 1254 was 84.4% after 25 d. Less chlorinated PCB congeners were more likely to be degraded by Anabaena PD-1 in comparison with highly chlorinated congeners. Meta - and para -chlorines in trichlorodiphenyls and tetrachlorobiphenyls were more susceptible to dechlorination than ortho -chlorines during the PCB-degradation process by Anabaena PD-1. Furthermore, Anabaena PD-1 can decompose dioxin-like PCBs. The percent biodegradation of 12 dioxin-like PCBs by strain PD-1 ranged from 37.4% to 68.4% after 25 days. Results above demonstrate that Anabaena PD-1 is a PCB-degrader with great potential for the in situ bioremediation of PCB-contaminated paddy soils.
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PubMed
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2012
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IF 3.461
Bo Yang,Shubo Deng,Gang Yu,Yonghong Lu,Hong Zhang,Jianzhong Xiao,Gang Chen,Xiaobing Cheng,Lili Shi
Nanoscale Al particles with average diameter of about 100 nm were employed to prepare Pd/Al nanoparticles (NPs) by chemical displacement deposition. It was proved that Pd 2+ acidic deposition solution was superior to its alkaline deposition solution in terms of Pd loading rate on Al NPs. The Pd/Al NPs were characterized by ICP–OES, SEM, TEM, XRD, BET and then used to explore hydrodechlorination (HDC) performance of 3-chlorophenol (3-CP) in aqueous solution. Major factors affecting HDC efficiency were investigated including Al substrate sizes, pH, Pd loadings in Pd/Al NPs, dosage of Pd/Al NPs, and temperature. The optimal results indicated that nanoscale Pd/Al bimetallic particles were highly effective for 3-CP HDC. HDC efficiency was only about 30% in 50 min reaction with micron sizes of Pd/Al particles (100–400 mesh), whereas it increased to 99.7% within 30 min using Pd/Al NPs at 25 °C. Aqueous pH presented remarkable effect on HDC and pH 3–4 was the optimum range for HDC as pH varied from 2 to 11. Pd loadings and Pd/Al dosages were optimized for highly effective HDC as 1.16 wt.% and 2 g/L, respectively. In addition, higher HDC performance was obtained while reaction temperature arrived at 45 °C and 0.389 mM of 3-CP could be completely dechlorinated into phenol only within 10 min reaction.
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高影响因子
Journal of Physical Chemistry C
·
2015
·
IF 4.772
Genlei Zhang,Zhaoyan Liu,Zhengli Xiao,Jiale Huang,Qingbiao Li,Yuxin Wang,Daohua Sun
Nanoparticles of Au–Pd with core–shell structure were synthesized through the coreduction of HAuCl4 and Na2PdCl4 in aqueous media by using cetyltrimethylammonium chloride as a reducing agent. The morphology and structure of the core–shell NPs were confirmed by transmission electron microscopy, X-ray diffraction, and UV–vis spectroscopy. We further demonstrate that the core–shell structure is formed as a synergistic result of low interfacial energy and small lattice mismatch between Au and Pd, different redox potentials of PdCl42–/Pd and AuCl4–/Au, and low reduction rates of HAuCl4 and Na2PdCl4. The catalyst of Au–Pd core–shell nanoparticles supported on Ni2P–graphite nanoplatelets (Au@Pd/Ni2P-GNPs) exhibits a noticeably higher activity than Pd and Pt catalysts in electrochemical ethanol oxidation. Moreover, we show that the activity and stability of Au–Pd core–shell for ethanol oxidation can be significantly enhanced using Ni2P nanoparticles as a cocatalyst. The prepared Au@Pd/Ni2P-GNPs catalyst exhibits a current density of 1.348 A mg–1metal, which is 2.1 times as high as that of Au@Pd/GNPs without Ni2P nanoparticles deposited.
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JOURNAL OF MOLECULAR CATALYSIS A-CHEMICAL
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2015
·
IF 3.615
Yansheng Liu,Bo Qiao,Xinlin Li,Xuanduong Le,Wei Zhang,Jiantai Ma
Palladium metal nanoparticles have been applied to hydrodechlorination of chlorophenols in contaminated water using H 2 as a clean and sustainable reductant. However, there are two major challenges to widespread technology adoption which are the activity loss caused by nanoparticle aggregation and the difficulty of nanoparticle recovery. In this study, a synthesis of a core-shell structured catalyst with encapsulated Pd nanoparticles has been given and whose catalytic activity has been tested in hydrodechlorination of chlorophenols under 1 atm H 2 at room temperature. The catalyst material consists of a nonporous silica core decorated with Pd nanoparticles that are further encapsulated within an ordered mesoporous silica shell. Well-defined mesopores (2.4 nm) provide a physical barrier to prevent Pd nanoparticle (∼10 nm) movement, aggregation and detachment from the support into water. Compared with some supported Pd catalysts such as Pd/AC and Pd/Al 2 O 3, SiO 2 /Pd@m-SiO 2 exhibits higher catalytic performance. After 5 times of recycling, catalytic activity of SiO 2 /Pd@m-SiO 2 reduces slightly and this result confirms the good recyclability of SiO 2 /Pd@m-SiO 2 . The function of the mesoporous shell, preventing aggregation of active nanoparticles, suggests a promising general strategy of using metal nanoparticle catalysts for water purification and related aqueous-phase applications.
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高影响因子
ELECTROCHIMICA ACTA
·
2014
·
IF 4.086
Jie-Ning Zheng,Ming Zhang,Fang-Fang Li,Shan-Shan Li,Ai-Jun Wang,Jiu-Ju Feng
In this report, a simple and rapid method was developed for the large-scaled synthesis of well-defined Pd nanochains based on one-pot wet-chemical reduction of PdCl 2 with KBH 4 , with the assistance of octylphenoxypolyethoxyethanol (OP-10) as a growth directing agent. The concentration of OP-10, the strength of a reducing agent and its amount, and the reaction temperature were demonstrated essential for preparation of the Pd nanocrystals. Furthermore, the as-prepared Pd nanochains exhibited a higher electrochemically active surface area and the enhanced electrocatalytic performance for formic acid oxidation in acid media, compared with the Pd nanoparticles.
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高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
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2013
·
IF 2.39
Zhang-Ying Lv,Yao Fei,Wan-Yi Chen,Yan-Fei Tan,Chao-Qun Sun,Jian-Rong Chen,Ai-Jun Wang,Jiu-Ju Feng
In this report, a simple, facile, controllable, and green one-step electrochemical co-deposition method was developed for the preparation of hierarchical wheat-like Au–Pd heterostructures on a glassy carbon electrode (GCE) without any template or surfactant, only using l -glutamic acid as a growth directing agent. The control experiments associated with the applied potential, the molar ratio of HAuCl 4 to PdCl 2 , electrodeposition time, and concentration of l -glutamic acid were investigated in details. Meanwhile, the electrochemical experiments demonstrate the superior electrocatalytic activity of the Au–Pd heterostructures toward methanol oxidation, achieving a maximum catalytic current density of 45.8 mA cm −2 in the presence of 0.5 M methanol, much larger than those on pure Au (5.4 mA cm −2 ) or Pd (25.0 mA cm −2 ) under the same conditions.
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高影响因子
Catalysts
·
2015
·Vol. 5
·期 3
·1388-1398
·
IF 2
Long-Long Wang,Xiao-Lu Cao,Ya-Jun Wang,Qiao-Xia Li
The newly proposed mimetic underpotential deposition (MUPD) technique was extended to modify Pd surfaces with Sb through immersing a Pd film electrode or dispersing Pd/C powder in a Sb(III)-containing solution blended with ascorbic acid (AA). The introduction of AA shifts down the open circuit potential of Pd substrate available to achieve suitable Sb modification. The electrocatalytic activity and long-term stability towards HCOOH electrooxidation of the Sb modified Pd surfaces (film electrode or powder catalyst) by MUPD is superior than that of unmodified Pd and Sb modified Pd surfaces by conventional UPD method. The enhancement of electrocatalytic performance is due to the third body effect and electronic effect, as well as bi-functional mechanism induced by Sb modification which result in increased resistance against CO poisoning.Keywords:formic acid oxidation;palladium;Sb modification;mimetic underpotential deposition
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高影响因子
RSC Advances
·
2016
·Vol. 6
·期 47
·41572-41579
·
IF 3.289
Wenjing Song,Xiuna Liu,Shaoyang Jiang,Zhou Chen,Weizheng Weng,I. Rodríguez-Ramos,Xiaodong Yi,Weiping Fang
A series of catalysts comprising well-distributed Pd nanoparticles incorporated on silylated SiO2 were fabricated by the wet impregnation method and investigated in the selective hydrogenation of paracetamol to 4-acetamidocyclohexanone. The catalysts calcined at different temperatures were characterized by TG, FT-IR, N2 physisorption, TPR and XPS. The results showed that organic modification led to a catalyst surface composed of stable Si–(CH3)3 species even after calcination at 300 °C. Also, changes occurred in the size and electronic properties of the Pd particles through the different amounts of grafted groups on the SiO2 support. The mode of adsorption of the paracetamol molecule was influenced by the quite bulky organic groups on the support, resulting in a significant improvement in selectivity towards 4-acetamidocyclohexanone and preventing full hydrogenation to some extent. The best result was obtained on the silylated Pd catalyst calcined at 500 °C, with 64.9% selectivity to keto at the paracetamol conversion of 60.5%, while the non-silylated SiO2 supported Pd catalyst gave 4-acetamidocyclohexanone selectivity of 29.1% at 53.8% conversion.
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高影响因子
RSC Advances
·
2016
·Vol. 6
·期 73
·69045-69051
·
IF 3.289
Hezhan Jiang,Xiaolong Yu,Xiaolun Peng,Haifu Zhang,Renfeng Nie,Xinhuan Lu,Dan Zhou,Qinghua Xia
Highly mesoporous carbon nitrides (CN) are synthesized through a simple polymerization reaction, including ethylenediamine (EDA), organic chlorides, with nano SiO2 as a hard-template. The degree of polymerization of the as-synthesized CN can easily be controlled by varying the organic chlorides. The CN derived from chloroform exhibits a low degree of polymerization, along with a high specific surface area of 315.9 m2 g−1 and pore volume of 0.87 cm3 g−1, in which the mesopore volume proportion reaches as high as 90.9%. Owing to the rich N groups (15.6 wt%), this basic network with open channels renders homogeneously dispersed Pd coordinated in the mesoporous carbonaceous framework and creates a highly active and stable Pd/CN catalyst for the selective hydrodeoxygenation of vanillin at low pressure (<1 MPa) and temperature (<70 °C). The best TOF reaches 295.4 h−1, and the Pd/CN catalyst can be used at least 6 times without obvious loss of its catalytic performance.
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JOURNAL OF THE ENERGY INSTITUTE
·
2017
·
IF 3.204
Qifu Huang,Wenzhi Li,Qizhao Lin,Xusheng Zheng,Haibin Pan,Dong Pi,Chunyu Shao,Chao Hu,Haitao Zhang
In this paper, the catalyst of Pd–NiCo 2 O 4 /SiO 2 was prepared and applied to the catalytic combustion of lean methane. Pd and NiCo 2 O 4 nanoparticles were uniformly distributed on the SiO 2 support, so that every Pd or NiCo 2 O 4 nanoparticle was separated from each other by another component. Comparing with Co 3 O 4 /SiO 2 , NiCo 2 O 4 /SiO 2 , Pd–Co 3 O 4 /SiO 2 and Pd#NiCo 2 O 4 /SiO 2 (catalysts without uniform distribution of Pd and NiCo 2 O 4 nanoparticles), Pd–NiCo 2 O 4 /SiO 2 had the highest catalytic activity in the catalytic combustion of lean methane, with a methane total conversion temperature at 378 °C. In addition, the high activity did not decrease during the long time reaction, which showed good thermal stability . TEM and BET results showed that the nanoparticle sizes of Pd and NiCo 2 O 4 were very small. The XRD patterns indicated that the Pd nanoparticles were highly dispersed on the surface of SiO 2 . The XPS spectra demonstrated the formation of NiCO 2 O 4 , the presence of enough active oxygen species on the catalyst surface and the high ratio of PdO/Pd 0 . The enhanced influence of Ni introduction was also proved by comparison tests. All these results indicated that the high catalytic activity of Pd–NiCo 2 O 4 /SiO 2 mainly comes from the nanoparticle distribution and the Ni cation enhancement.
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