A "trimurti" heterostructured hybrid with an intimate CoO/CoxP interface as a robust bifunctional air electrode for rechargeable Zn–air batteries

2020 ◽  
Vol 8 (18) ◽  
pp. 9177-9184 ◽  
Author(s):  
Yue Niu ◽  
Meiling Xiao ◽  
Jianbing Zhu ◽  
Taotao Zeng ◽  
Jingde Li ◽  
...  
Keyword(s):  
Synergistic Effects ◽  
Catalytic Efficiency ◽  
Structural Features ◽  
Air Electrode ◽  
Bifunctional Air Electrode

The synergistic effects of triphasic cobalt-based nanoparticles andtheir superior structural features enable unprecedented bifunctional catalytic efficiency and durability.

An Efficient Bifunctional Air Electrode for Reversible Protonic Ceramic Electrochemical Cells

2021 ◽  
pp. 2105386
Author(s):  
Yucun Zhou ◽  
Weilin Zhang ◽  
Nicholas Kane ◽  
Zheyu Luo ◽  
Kai Pei ◽  
...  
Keyword(s):  
Electrochemical Cells ◽  
Air Electrode ◽  
Bifunctional Air Electrode

scholarly journals Porous ZnO/Co3O4/N-doped carbon nanocages synthesized via pyrolysis of complex metal–organic framework (MOF) hybrids as an advanced lithium-ion battery anode

2019 ◽  
Vol 75 (7) ◽  
pp. 969-978 ◽  
Author(s):  
Erbo Cheng ◽  
Shoushuang Huang ◽  
Dayong Chen ◽  
Ruting Huang ◽  
Qing Wang ◽  
...  
Keyword(s):  
Metal Oxides ◽  
Synergistic Effects ◽  
Metal Organic Framework ◽  
Lithium Ion ◽  
Reversible Capacity ◽  
Structural Features ◽  
High Rate ◽  
Discharge Process ◽  
Retention Capacity ◽  
Metal Organic

Metal oxides have a large storage capacity when employed as anode materials for lithium-ion batteries (LIBs). However, they often suffer from poor capacity retention due to their low electrical conductivity and huge volume variation during the charge–discharge process. To overcome these limitations, fabrication of metal oxides/carbon hybrids with hollow structures can be expected to further improve their electrochemical properties. Herein, ZnO-Co3O4 nanocomposites embedded in N-doped carbon (ZnO-Co3O4@N-C) nanocages with hollow dodecahedral shapes have been prepared successfully by the simple carbonizing and oxidizing of metal–organic frameworks (MOFs). Benefiting from the advantages of the structural features, i.e. the conductive N-doped carbon coating, the porous structure of the nanocages and the synergistic effects of different components, the as-prepared ZnO-Co3O4@N-C not only avoids particle aggregation and nanostructure cracking but also facilitates the transport of ions and electrons. As a result, the resultant ZnO-Co3O4@N-C shows a discharge capacity of 2373 mAh g−1 at the first cycle and exhibits a retention capacity of 1305 mAh g−1 even after 300 cycles at 0.1 A g−1. In addition, a reversible capacity of 948 mAh g−1 is obtained at a current density of 2 A g−1, which delivers an excellent high-rate cycle ability.

scholarly journals A structural and kinetic survey of GH5_4 endoglucanases reveals determinants of broad substrate specificity and opportunities for biomass hydrolysis

2020 ◽  
Vol 295 (51) ◽  
pp. 17752-17769
Author(s):  
Evan M. Glasgow ◽  
Elias I. Kemna ◽  
Craig A. Bingman ◽  
Nicole Ing ◽  
Kai Deng ◽  
...  
Keyword(s):  
Substrate Specificity ◽  
Protein Design ◽  
Plant Biomass ◽  
Catalytic Efficiency ◽  
Structural Features ◽  
Glycoside Hydrolases ◽  
Design Strategies ◽  
Biomass Hydrolysis ◽  
Diverse Range ◽  
Broad Specificity

Broad-specificity glycoside hydrolases (GHs) contribute to plant biomass hydrolysis by degrading a diverse range of polysaccharides, making them useful catalysts for renewable energy and biocommodity production. Discovery of new GHs with improved kinetic parameters or more tolerant substrate-binding sites could increase the efficiency of renewable bioenergy production even further. GH5 has over 50 subfamilies exhibiting selectivities for reaction with β-(1,4)–linked oligo- and polysaccharides. Among these, subfamily 4 (GH5_4) contains numerous broad-selectivity endoglucanases that hydrolyze cellulose, xyloglucan, and mixed-linkage glucans. We previously surveyed the whole subfamily and found over 100 new broad-specificity endoglucanases, although the structural origins of broad specificity remained unclear. A mechanistic understanding of GH5_4 substrate specificity would help inform the best protein design strategies and the most appropriate industrial application of broad-specificity endoglucanases. Here we report structures of 10 new GH5_4 enzymes from cellulolytic microbes and characterize their substrate selectivity using normalized reducing sugar assays and MS. We found that GH5_4 enzymes have the highest catalytic efficiency for hydrolysis of xyloglucan, glucomannan, and soluble β-glucans, with opportunistic secondary reactions on cellulose, mannan, and xylan. The positions of key aromatic residues determine the overall reaction rate and breadth of substrate tolerance, and they contribute to differences in oligosaccharide cleavage patterns. Our new composite model identifies several critical structural features that confer broad specificity and may be readily engineered into existing industrial enzymes. We demonstrate that GH5_4 endoglucanases can have broad specificity without sacrificing high activity, making them a valuable addition to the biomass deconstruction toolset.

scholarly journals Molecular engineering of myosin

2004 ◽  
Vol 359 (1452) ◽  
pp. 1907-1912 ◽  
Author(s):  
K. C. Holmes ◽  
D. R. Trentham ◽  
R. Simmons ◽  
Dietmar J. Manstein
Keyword(s):  
Protein Engineering ◽  
Protein Design ◽  
Catalytic Efficiency ◽  
Building Blocks ◽  
Structural Features ◽  
Molecular Engineering ◽  
Actin Binding ◽  
Myosin Motor ◽  
Nucleotide Binding Sites ◽  
Molecular Building Blocks

Protein engineering and design provide excellent tools to investigate the principles by which particular structural features relate to the mechanisms that underlie the biological function of a protein. In addition to studies aimed at dissecting the communication pathways within enzymes, recent advances in protein engineering approaches make it possible to generate enzymes with increased catalytic efficiency and specifically altered or newly introduced functions. Here, two approaches using state–of–the–art protein design and engineering are described in detail to demonstrate how key features of the myosin motor can be changed in a specific and predictable manner. First, it is shown how replacement of an actin–binding surface loop with synthetic sequences, whose flexibility and charge density is varied, can be employed to manipulate the actin affinity, the catalytic activity and the efficiency of coupling between actin– and nucleotide–binding sites of myosin motor constructs. Then the use of pre–existing molecular building blocks, which are derived from unrelated proteins, is described for manipulating the velocity and even the direction of movement of recombinant myosins.

scholarly journals Effect of oxygenation on electrocatalysis of La0.6Ca0.4CoO3−x in bifunctional air electrode

2003 ◽  
Vol 48 (11) ◽  
pp. 1567-1571 ◽  
Author(s):  
Nae-Lih Wu ◽  
Wei-Ren Liu ◽  
Sern-Jei Su
Keyword(s):  
Air Electrode ◽  
Bifunctional Air Electrode

Perovskite Ba0.5Sr0.5Co0.8Fe0.2O3-  as a Bifunctional Air Electrode for Zinc-Air Batteries

2013 ◽  
Vol 53 (30) ◽  
pp. 265-272 ◽  
Author(s):  
X.-Z. Yuan ◽  
W. Qu ◽  
J. Fahlman ◽  
D. G. Ivey ◽  
X. Zhang
Keyword(s):  
Air Electrode ◽  
Bifunctional Air Electrode ◽  
Zinc Air Batteries

Bifunctional Air Electrode for Metal‐Air Batteries

1980 ◽  
Vol 127 (3) ◽  
pp. 525-528 ◽  
Author(s):  
Lars Carlsson ◽  
Lars Öjefors
Keyword(s):  
Air Electrode ◽  
Bifunctional Air Electrode

scholarly journals Unravelling the diversity of glycoside hydrolase family 13 α-amylases from Lactobacillus plantarum WCFS1

2019 ◽  
Vol 18 (1) ◽  
Author(s):  
Laura Plaza-Vinuesa ◽  
Oswaldo Hernandez-Hernandez ◽  
F. Javier Moreno ◽  
Blanca de las Rivas ◽  
Rosario Muñoz
Keyword(s):  
Lactobacillus Plantarum ◽  
Glycoside Hydrolase ◽  
Catalytic Efficiency ◽  
Hydrolytic Activity ◽  
Structural Features ◽  
Biochemical Properties ◽  
Glycoside Hydrolase Family ◽  
Reaction Conditions ◽  
Genes Encoding ◽  
Hydrolysis Of

Abstract Background α-Amylases specifically catalyse the hydrolysis of the internal α-1, 4-glucosidic linkages of starch. Glycoside hydrolase (GH) family 13 is the main α-amylase family in the carbohydrate-active database. Lactobacillus plantarum WCFS1 possesses eleven proteins included in GH13 family. Among these, proteins annotated as maltose-forming α-amylase (Lp_0179) and maltogenic α-amylase (Lp_2757) were included. Results In this study, Lp_0179 and Lp_2757 L. plantarum α-amylases were structurally and biochemically characterized. Lp_2757 displayed structural features typical of GH13_20 subfamily which were absent in Lp_0179. Genes encoding Lp_0179 (Amy2) and Lp_2757 were cloned and overexpressed in Escherichia coli BL21(DE3). Purified proteins showed high hydrolytic activity on pNP-α-D-maltopyranoside, being the catalytic efficiency of Lp_0179 remarkably higher. In relation to the hydrolysis of starch-related carbohydrates, Lp_0179 only hydrolysed maltopentaose and dextrin, demonstrating that is an exotype glucan hydrolase. However, Lp_2757 was also able to hydrolyze cyclodextrins and other non-cyclic oligo- and polysaccharides, revealing a great preference towards α-1,4-linkages typical of maltogenic amylases. Conclusions The substrate range as well as the biochemical properties exhibited by Lp_2757 maltogenic α-amylase suggest that this enzyme could be a very promising enzyme for the hydrolysis of α-1,4 glycosidic linkages present in a broad number of starch-carbohydrates, as well as for the investigation of an hypothetical transglucosylation activity under appropriate reaction conditions.

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