Synthesis of Pd/Ru Bimetallic Nanoparticles by Escherichia coli and Potential as a Catalyst for Upgrading 5-Hydroxymethyl Furfural Into Liquid Fuel Precursors
Synthesis of Pd/Ru Bimetallic Nanoparticles by Escherichia coli and Potential as a Catalyst for Upgrading 5-Hydroxymethyl Furfural Into Liquid Fuel Precursors
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DOI：
10.3389/fmicb.2019.01276
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发表时间：
2019-06-20
影响因子：
5.2
通讯作者：
Macaskie, Lynne E.
中科院分区：
文献类型：
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作者：
Gomez-Bolivar, Jaime;Mikheenko, Iryna P.;Macaskie, Lynne E.
大肠杆菌细胞支持钌和钯-钌纳米颗粒（Bio-Ru和Bio-Pd/Ru纳米颗粒）的成核和生长。我们报道了一种合成这些monoclonal和coclonal纳米粒子的方法，以及它们在5-羟甲基糠醛（5-HMF）催化升级为2，5二甲基呋喃（DMF）中的应用。使用高分辨率透射电子显微镜与能量色散X射线微量分析（EDX）和高角度环形暗场（HAADF）的检查显示，仅使用Ru（III）时，Ru NP主要位于细胞表面，但仅在已经用Pd（0）（5重量%）预“接种”并负载等摩尔Ru的细胞中可见小的细胞内Ru-NP（尺寸类似于1-2 nm）。Pd（0）NPs分布在细胞质和细胞表面之间。细胞轴承5%Pd/5%Ru显示一些共定位的Pd和Ru，但不排除偶然的协会。负载至5wt%Pd/20wt%Ru的电池显示核-壳结构（Ru核，Pd壳）的证据。使用X射线光电子能谱（XPS）检查该电池表面材料显示Pd（0）和Pd（II）以及Ru（IV）和Ru（III），通过使用X射线吸收近边结构（XANES）和扩展X射线吸收精细结构（EXAFS）分析对本体材料进行分析来确认。Bio-Ru NP和Bio-Pd/Ru NP在5-HMF转化为2，5-DMF中均具有活性，但商业Ru/碳催化剂的性能超过5重量%的生物Ru四倍。虽然5wt%Pd/20wt%Ru实现了20%的DMF产率，但是在使用商业5-HMF的测试反应中，5wt%Pd/5wt%Ru生物催化剂的性能更高并且与商业5wt%Ru/C催化剂相当（>50%选择性）。5-通过淀粉和纤维素的热化学水解以及将5-HMF溶剂萃取到甲基四氢呋喃（MTHF）中来制备HMF。这里，用MTHF作为反应溶剂，商业Ru/C催化剂具有很小的活性（100%转化率，对DMF的选择性可忽略不计），而5wt%Pd/5wt%Ru生物催化剂从从水解产物提取的材料得到100%转化率和14%对DMF的选择性。结果表明，一种潜在的绿色方法，用于实现从生物质废物增加的能源潜力，以及显示一种生物基的途径，以制造一种几乎没有描述的可再生材料。
Escherichia coli cells support the nucleation and growth of ruthenium and ruthenium-palladium nanoparticles (Bio-Ru and Bio-Pd/Ru NPs). We report a method for the synthesis of these monometallic and bimetallic NPs and their application in the catalytic upgrading of 5-hydroxymethyl furfural (5-HMF) to 2,5 dimethylfuran (DMF). Examination using high resolution transmission electron microscopy with energy dispersive X-ray microanalysis (EDX) and high angle annular dark field (HAADF) showed Ru NPs located mainly at the cell surface using Ru(III) alone but small intracellular Ru-NPs (size similar to 1-2 nm) were visible only in cells that had been pre-"seeded" with Pd(0) (5 wt%) and loaded with equimolar Ru. Pd(0) NPs were distributed between the cytoplasm and cell surface. Cells bearing 5% Pd/5% Ru showed some co-localization of Pd and Ru but chance associations were not ruled out. Cells loaded to 5 wt% Pd/20 wt% Ru showed evidence of core-shell structures (Ru core, Pd shell). Examination of this cell surface material using X-ray photoelectron spectroscopy (XPS) showed Pd(0) and Pd(II) and Ru(IV) and Ru(III), with confirmation by analysis of bulk material using X-ray absorption near edge structure (XANES) and extended X-ray absorption fine structure (EXAFS) analyses. Both Bio-Ru NPs and Bio-Pd/Ru NPs were active in the conversion of 5-HMF into 2,5-DMF but commercial Ru on carbon catalyst outperformed 5 wt% bio-Ru by fourfold. While 5 wt% Pd/20 wt% Ru achieved 20% yield of DMF the performance of the 5 wt% Pd/5 wt% Ru bio-catalyst was higher and comparable to the commercial 5 wt% Ru/C catalyst in a test reaction using commercial 5-HMF (>50% selectivity). 5-HMF was prepared by thermochemical hydrolysis of starch and cellulose with solvent extraction of 5-HMF into methyltetrahydrofuran (MTHF). Here, with MTHF as the reaction solvent the commercial Ru/C catalyst had little activity (100% conversion, negligible selectivity to DMF) whereas the 5 wt% Pd/5 wt% Ru bio-bimetallic gave 100% conversion and 14% selectivity to DMF from material extracted from hydrolyzates. The results indicate a potential green method for realizing increased energy potential from biomass wastes as well as showing a bio-based pathway to manufacturing a scarcely described bimetallic material.