Scalable one-step production of electrochemically exfoliated graphene decorated with transition metal oxides for high-performance supercapacitors

Nanoscale ◽  
2021 ◽  
Author(s):  
Adrián Romaní Vázquez ◽  
Christof Neumann ◽  
Mino Borrelli ◽  
Huanhuan Shi ◽  
Matthias Kluge ◽  
...  

Graphene and related materials have been widely studied for their superior properties in a wide field of applications. However, large-scale production remains a critical challenge to enable commercial acceptance. Here,...

Energies ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1940
Author(s):  
Muhammad Usman Naseer ◽  
Ants Kallaste ◽  
Bilal Asad ◽  
Toomas Vaimann ◽  
Anton Rassõlkin

This paper presents current research trends and prospects of utilizing additive manufacturing (AM) techniques to manufacture electrical machines. Modern-day machine applications require extraordinary performance parameters such as high power-density, integrated functionalities, improved thermal, mechanical & electromagnetic properties. AM offers a higher degree of design flexibility to achieve these performance parameters, which is impossible to realize through conventional manufacturing techniques. AM has a lot to offer in every aspect of machine fabrication, such that from size/weight reduction to the realization of complex geometric designs. However, some practical limitations of existing AM techniques restrict their utilization in large scale production industry. The introduction of three-dimensional asymmetry in machine design is an aspect that can be exploited most with the prevalent level of research in AM. In order to take one step further towards the enablement of large-scale production of AM-built electrical machines, this paper also discusses some machine types which can best utilize existing developments in the field of AM.


2008 ◽  
Vol 74 (10) ◽  
pp. 2967-2975 ◽  
Author(s):  
Ryan D. Woodyer ◽  
Nathan J. Wymer ◽  
F. Michael Racine ◽  
Shama N. Khan ◽  
Badal C. Saha

ABSTRACT A new synthetic platform with potential for the production of several rare sugars, with l-ribose as the model target, is described. The gene encoding the unique NAD-dependent mannitol-1-dehydrogenase (MDH) from Apium graveolens (garden celery) was synthetically constructed for optimal expression in Escherichia coli. This MDH enzyme catalyzes the interconversion of several polyols and their l-sugar counterparts, including the conversion of ribitol to l-ribose. Expression of recombinant MDH in the active form was successfully achieved, and one-step purification was demonstrated. Using the created recombinant E. coli strain as a whole-cell catalyst, the synthetic utility was demonstrated for production of l-ribose, and the system was improved using shaken flask experiments. It was determined that addition of 50 to 500 μM ZnCl2 and addition of 5 g/liter glycerol both improved production. The final levels of conversion achieved were >70% at a concentration of 40 g/liter and >50% at a concentration of 100 g/liter. The best conditions determined were then scaled up to a 1-liter fermentation that resulted in 55% conversion of 100 g/liter ribitol in 72 h, for a volumetric productivity of 17.4 g liter−1 day−1. This system represents a significantly improved method for the large-scale production of l-ribose.


2015 ◽  
Vol 719-720 ◽  
pp. 123-126
Author(s):  
Jin Sun ◽  
Qing Zhong Xue ◽  
Yong Gang Du ◽  
Fu Jun Xia ◽  
Qi Kai Guo

Porous graphene is a collection of graphene-related materials which exhibits properties distinct from those of graphene, and it has widespread potential applications in various fields. Several approaches have been developed to produce porous graphene. However, the large-scale production of porous graphene nanosheets still remains a great challenge. Moreover, the costs of some methods are prohibitive for its commercial production and the processes are too complicated and time-consuming. In this work, we propose a simple and green method by which graphene nanosheets can be etched by sodium hydroxide under autogenous pressure at 180 °C. The morphologies and surface elements of the porous graphene nanosheets and sizes of pores were characterized. It is demonstrated that the one-step etching of graphene nanosheets is an effective method to obtain large-scale porous graphene nanosheets with high and uniform porosity. The pores in the porous graphene nanosheets were 6 nm depth (the same as the thickness of the graphene nanosheets) and 30-50 nm width.


RSC Advances ◽  
2015 ◽  
Vol 5 (47) ◽  
pp. 37830-37836 ◽  
Author(s):  
Wei Wei ◽  
Linlin Guo ◽  
Xiaoyang Qiu ◽  
Peng Qu ◽  
Maotian Xu ◽  
...  

Although many routes have been developed that can efficiently improve the electrochemical performance of LiFePO4 cathodes, few of them meet the urgent industrial requirements of large-scale production, low cost and excellent performance.


2021 ◽  
Author(s):  
Jingyue Wang ◽  
Xinan Xu ◽  
Fangkun Zhao ◽  
Nan Yin ◽  
Zhijiang Zhou ◽  
...  

Abstract Purpose: The yield of levan extracted from microbial fermentation broth is low, so in vitro catalytic synthesis of levan by levansucrase is expected to be one of the industrial production approaches of levan. Methods: A recombinant plasmid pET-28a-AcmA-Z constructed in the previous study was used to produce levansucrase. The effects of temperature, pH, and metal ions on the levan formation activity of the levansucrase were investigated. The polymer was analyzed by means of HPIC, FTIR, NMR techniques.Results: The recombinant levansucrase could be easily purified in one step and the purified enzyme had a single band clearly visible in SDS-PAGE. The conditions for enzymatic reactions was optimal at pH 5.2 and 40 ℃, and the activity of enzymes was stimulated by K+ and Ca2+. The yield of levan biosynthesis from 10% (w/v) sucrose with 6.45 U/g sucrose of levansucrase was 30.6 g/L. The molecular weight of the levan was about 1.56×106 Da, as measured by GPC. HPIC analysis showed that the monosaccharide composition of the levan was fructose and glucose. The results of FTIR and NMR analysis indicated that the polymer produced by the recombinant levansucrase was β-(2, 6) levan.Conclusions: The results of this study provide a basis for large-scale production of levan by enzymatic method.


CrystEngComm ◽  
2018 ◽  
Vol 20 (21) ◽  
pp. 2989-2995 ◽  
Author(s):  
Weikun Chen ◽  
Pinqiang Dai ◽  
Chunfu Hong ◽  
Chan Zheng ◽  
Weiguo Wang ◽  
...  

We demonstrate a green method based on sonochemistry for large-scale production of akaganéite nanoparticles and assemblies in low cost.


2011 ◽  
Vol 675-677 ◽  
pp. 223-226
Author(s):  
Hong Zhao ◽  
Jin Hua Yao ◽  
Shu Bao Jin ◽  
Li Jun Liang

Strong alkali anion exchange resin was employed as a hydroxyl source in the synthesis. OH- releasing rates were easily controlled by varying precursor salts, salt concentrations and temperatures, etc. The ratio between the nucleation speed and the speed of oxide crystallite growth was adjusted to favor the anisotropic growth of the crystal. Zinc and aluminum nano-sized oxide were obtained in various morphologies. X-ray diffraction (XRD), scanning electron microscope (SEM) and Energy Dispersion Spectroscopy (EDS) were employed to characterize the products. It is ascertained that the surface reaction on the resin and the mechanical grinding are the key steps in controlling the product morphology. The results show the flexibility and possibility of large scale production of various nano metal oxides and as well as mixed oxides.


2018 ◽  
Vol 1 (12) ◽  
pp. 6986-6991 ◽  
Author(s):  
Xing Gao ◽  
Ying Du ◽  
Junwen Zhou ◽  
Siwu Li ◽  
Pengfei Qi ◽  
...  

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