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Microbial synthesis of Pd/Fe3O4, Au/Fe3O4 and PdAu/Fe3O4 nanocomposites for catalytic reduction of nitroaromatic compounds.

Tuo Y, Liu G, Dong B, Zhou J, Wang A, Wang J, Jin R, Lv H, Dou Z, Huang W - Sci Rep (2015)

Bottom Line: All these three kinds of magnetic nanocomposites can catalyze the reduction of 4-nitrophenol and some other nitroaromatic compounds by NaBH4.PdAu/Fe3O4 can be reused in at least eight successive cycles of 4-nitrophenol reduction.The biosynthesis approach presented here does not require harmful agents or rigorous conditions and thus provides facile and environmentally benign choice for the preparation of magnetic noble metal nanocatalysts.

View Article: PubMed Central - PubMed

Affiliation: Key Laboratory of Industrial Ecology and Environmental Engineering, Ministry of Education, School of Environmental Science and Technology, Dalian University of Technology, Dalian, 116024, China.

ABSTRACT
Magnetically recoverable noble metal nanoparticles are promising catalysts for chemical reactions. However, the chemical synthesis of these nanocatalysts generally causes environmental concern due to usage of toxic chemicals under extreme conditions. Here, Pd/Fe3O4, Au/Fe3O4 and PdAu/Fe3O4 nanocomposites are biosynthesized under ambient and physiological conditions by Shewanella oneidensis MR-1. Microbial cells firstly transform akaganeite into magnetite, which then serves as support for the further synthesis of Pd, Au and PdAu nanoparticles from respective precursor salts. Surface-bound cellular components and exopolysaccharides not only function as shape-directing agent to convert some Fe3O4 nanoparticles to nanorods, but also participate in the formation of PdAu alloy nanoparticles on magnetite. All these three kinds of magnetic nanocomposites can catalyze the reduction of 4-nitrophenol and some other nitroaromatic compounds by NaBH4. PdAu/Fe3O4 demonstrates higher catalytic activity than Pd/Fe3O4 and Au/Fe3O4. Moreover, the magnetic nanocomposites can be easily recovered through magnetic decantation after catalysis reaction. PdAu/Fe3O4 can be reused in at least eight successive cycles of 4-nitrophenol reduction. The biosynthesis approach presented here does not require harmful agents or rigorous conditions and thus provides facile and environmentally benign choice for the preparation of magnetic noble metal nanocatalysts.

No MeSH data available.


Crystalline structure.(a) XRD patterns of (i) Pd/Fe3O4, (ii) Au/Fe3O4 and (iii) PdAu/Fe3O4. (b) Magnification of the peaks (111) and (200) in the 2θ range of 36–48°.
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f2: Crystalline structure.(a) XRD patterns of (i) Pd/Fe3O4, (ii) Au/Fe3O4 and (iii) PdAu/Fe3O4. (b) Magnification of the peaks (111) and (200) in the 2θ range of 36–48°.

Mentions: As shown in Fig. 2a, for Pd/Fe3O4 nanocomposite, the observed XRD peaks at 2θ = 30.18°, 35.54°, 43.18°, 53.58°, 57.16° and 62.78° can be indexed to (220), (311), (400), (422), (511) and (440) planes of fcc Fe3O4, respectively (JCPDS 19-0629). In addition, the diffraction peaks ascribed to (111) and (200) planes of metallic fcc Pd (JCPDS 46-1043) were clearly observed at 2θ = 39.90° and 46.54°, respectively. For Au/Fe3O4 nanocomposite, the diffraction peaks at 2θ = 38.12°, 44.32°, 64.64°, 77.72° and 81.80° can be indexed to the (111), (200), (220), (311) and (222) planes of fcc Au (JCPDS 04-0784), respectively. The diffraction peaks of Fe3O4 became weak in Au/Fe3O4, which may be due to the heavy atom effect of Au coating on the Fe3O4 supports2021. For PdAu/Fe3O4 nanocomposite, besides the characteristic peaks of Fe3O4, the (111) and (200) peaks of PdAu (2θ = 38.24° and 44.48°) locate between those of monometallic fcc Pd and Au (Fig. 2b), again indicating the formation of bimetallic alloy2223.


Microbial synthesis of Pd/Fe3O4, Au/Fe3O4 and PdAu/Fe3O4 nanocomposites for catalytic reduction of nitroaromatic compounds.

Tuo Y, Liu G, Dong B, Zhou J, Wang A, Wang J, Jin R, Lv H, Dou Z, Huang W - Sci Rep (2015)

Crystalline structure.(a) XRD patterns of (i) Pd/Fe3O4, (ii) Au/Fe3O4 and (iii) PdAu/Fe3O4. (b) Magnification of the peaks (111) and (200) in the 2θ range of 36–48°.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4550933&req=5

f2: Crystalline structure.(a) XRD patterns of (i) Pd/Fe3O4, (ii) Au/Fe3O4 and (iii) PdAu/Fe3O4. (b) Magnification of the peaks (111) and (200) in the 2θ range of 36–48°.
Mentions: As shown in Fig. 2a, for Pd/Fe3O4 nanocomposite, the observed XRD peaks at 2θ = 30.18°, 35.54°, 43.18°, 53.58°, 57.16° and 62.78° can be indexed to (220), (311), (400), (422), (511) and (440) planes of fcc Fe3O4, respectively (JCPDS 19-0629). In addition, the diffraction peaks ascribed to (111) and (200) planes of metallic fcc Pd (JCPDS 46-1043) were clearly observed at 2θ = 39.90° and 46.54°, respectively. For Au/Fe3O4 nanocomposite, the diffraction peaks at 2θ = 38.12°, 44.32°, 64.64°, 77.72° and 81.80° can be indexed to the (111), (200), (220), (311) and (222) planes of fcc Au (JCPDS 04-0784), respectively. The diffraction peaks of Fe3O4 became weak in Au/Fe3O4, which may be due to the heavy atom effect of Au coating on the Fe3O4 supports2021. For PdAu/Fe3O4 nanocomposite, besides the characteristic peaks of Fe3O4, the (111) and (200) peaks of PdAu (2θ = 38.24° and 44.48°) locate between those of monometallic fcc Pd and Au (Fig. 2b), again indicating the formation of bimetallic alloy2223.

Bottom Line: All these three kinds of magnetic nanocomposites can catalyze the reduction of 4-nitrophenol and some other nitroaromatic compounds by NaBH4.PdAu/Fe3O4 can be reused in at least eight successive cycles of 4-nitrophenol reduction.The biosynthesis approach presented here does not require harmful agents or rigorous conditions and thus provides facile and environmentally benign choice for the preparation of magnetic noble metal nanocatalysts.

View Article: PubMed Central - PubMed

Affiliation: Key Laboratory of Industrial Ecology and Environmental Engineering, Ministry of Education, School of Environmental Science and Technology, Dalian University of Technology, Dalian, 116024, China.

ABSTRACT
Magnetically recoverable noble metal nanoparticles are promising catalysts for chemical reactions. However, the chemical synthesis of these nanocatalysts generally causes environmental concern due to usage of toxic chemicals under extreme conditions. Here, Pd/Fe3O4, Au/Fe3O4 and PdAu/Fe3O4 nanocomposites are biosynthesized under ambient and physiological conditions by Shewanella oneidensis MR-1. Microbial cells firstly transform akaganeite into magnetite, which then serves as support for the further synthesis of Pd, Au and PdAu nanoparticles from respective precursor salts. Surface-bound cellular components and exopolysaccharides not only function as shape-directing agent to convert some Fe3O4 nanoparticles to nanorods, but also participate in the formation of PdAu alloy nanoparticles on magnetite. All these three kinds of magnetic nanocomposites can catalyze the reduction of 4-nitrophenol and some other nitroaromatic compounds by NaBH4. PdAu/Fe3O4 demonstrates higher catalytic activity than Pd/Fe3O4 and Au/Fe3O4. Moreover, the magnetic nanocomposites can be easily recovered through magnetic decantation after catalysis reaction. PdAu/Fe3O4 can be reused in at least eight successive cycles of 4-nitrophenol reduction. The biosynthesis approach presented here does not require harmful agents or rigorous conditions and thus provides facile and environmentally benign choice for the preparation of magnetic noble metal nanocatalysts.

No MeSH data available.