scholarly journals Mechanochemical synthesis of graphene oxide-supported transition metal catalysts for the oxidation of isoeugenol to vanillin

2017 ◽  
Vol 13 ◽  
pp. 1439-1445 ◽  
Author(s):  
Ana Franco ◽  
Sudipta De ◽  
Alina M Balu ◽  
Araceli Garcia ◽  
Rafael Luque
Keyword(s):  
Graphene Oxide ◽  
Transition Metal ◽  
Large Scale ◽  
Metal Catalysts ◽  
Transition Metal Catalysts ◽  
Efficient Production ◽  
Scale Production ◽  
Supported Metal Catalysts ◽  
Co Catalysts ◽  
Large Scale Production

Vanillin is one of the most commonly used natural products, which can also be produced from lignin-derived feedstocks. The chemical synthesis of vanillin is well-established in large-scale production from petrochemical-based starting materials. To overcome this problem, lignin-derived monomers (such as eugenol, isoeugenol, ferulic acid etc.) have been effectively used in the past few years. However, selective and efficient production of vanillin from these feedstocks still remains an issue to replace the existing process. In this work, new transition metal-based catalysts were proposed to investigate their efficiency in vanillin production. Reduced graphene oxide supported Fe and Co catalysts showed high conversion of isoeugenol under mild reaction conditions using H2O2 as oxidizing agent. Fe catalysts were more selective as compared to Co catalysts, providing a 63% vanillin selectivity at 61% conversion in 2 h. The mechanochemical process was demonstrated as an effective approach to prepare supported metal catalysts that exhibited high activity for the production of vanillin from isoeugenol.

scholarly journals The Effect of Iron Impurities on Transition Metal Catalysts for the Oxygen Evolution Reaction in Alkaline Environment: Activity Mediators or Active Sites?

2020 ◽  
Author(s):  
Ioannis Spanos ◽  
Justus Masa ◽  
Aleksandar Zeradjanin ◽  
Robert Schlögl
Keyword(s):  
Transition Metal ◽  
Oxygen Evolution ◽  
Oxygen Evolution Reaction ◽  
Active Sites ◽  
Water Electrolysis ◽  
Metal Catalysts ◽  
Transition Metal Catalysts ◽  
Alkaline Water Electrolysis ◽  
Co Catalysts ◽  
Model Transition

AbstractThere is an ongoing debate on elucidating the actual role of Fe impurities in alkaline water electrolysis, acting either as reactivity mediators or as co-catalysts through synergistic interaction with the main catalyst material. This perspective summarizes the most prominent oxygen evolution reaction (OER) mechanisms mostly for Ni-based oxides as model transition metal catalysts and highlights the effect of Fe incorporation on the catalyst surface in the form of impurities originating from the electrolyte or co-precipitated in the catalyst lattice, in modulating the OER reaction kinetics, mechanism and stability. Graphic Abstract

Large-scale production of high-quality reduced graphene oxide

2013 ◽  
Vol 233 ◽  
pp. 297-304 ◽  
Author(s):  
Shichoon Lee ◽  
Sung Hun Eom ◽  
Jin Suk Chung ◽  
Seung Hyun Hur
Keyword(s):  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Large Scale ◽  
Scale Production ◽  
High Quality ◽  
Large Scale Production ◽  
Reduced Graphene

scholarly journals Novel Green Synthesis of Graphene Layers using Zante Currants and Graphene Oxide

2018 ◽  
Vol 34 (6) ◽  
pp. 2832-2837 ◽  
Author(s):  
Mohd Zaid Ansari ◽  
Mohammad Nadeem Lone ◽  
Shabana Sajid ◽  
Weqar Ahmad Siddiqui
Keyword(s):  
Graphene Oxide ◽  
Large Scale ◽  
Uv Spectrophotometry ◽  
Scale Production ◽  
Graphene Layers ◽  
Large Scale Production ◽  
Reduced Graphene ◽  
Reduction Effect ◽  
First Time ◽  
Facile Route

The present work shows a facile route for the preparation of graphene layers and for the first time Zante currants extract used for the effective deoxygenation of graphene oxide has been reported. Zante currants (ZC) extract reduce effectively GO into few layered structures of graphene (FLG). The morphology of few layers graphene and graphene oxide (GO) were investigated by SEM and TEM. Reduction effect on graphene oxide confirm by other technique like Raman, FTIR, XRD and UV spectrophotometry. This procedure keep away the use of hazardous chemicals, thus providing a new hope for large scale production of chemically reduced graphene.

scholarly journals Efficient Production of l-Ribose with a Recombinant Escherichia coli Biocatalyst

2008 ◽  
Vol 74 (10) ◽  
pp. 2967-2975 ◽  
Author(s):  
Ryan D. Woodyer ◽  
Nathan J. Wymer ◽  
F. Michael Racine ◽  
Shama N. Khan ◽  
Badal C. Saha
Keyword(s):  
Escherichia Coli ◽  
Large Scale ◽  
Active Form ◽  
Apium Graveolens ◽  
Efficient Production ◽  
Scale Production ◽  
Gene Encoding ◽  
Large Scale Production ◽  
One Step ◽  
Rare Sugars

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.

scholarly journals A Green Approach for Highly Reduction of Graphene Oxide by Supercritical Fluid

2014 ◽  
Vol 1004-1005 ◽  
pp. 1013-1016 ◽  
Author(s):  
Chang Yi Kong ◽  
Yuuki Shiratori ◽  
Takeshi Sako ◽  
Futoshi Iwata
Keyword(s):  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Supercritical Fluid ◽  
Large Scale ◽  
Scale Production ◽  
Graphene Oxides ◽  
Practical Applications ◽  
Green Approach ◽  
Large Scale Production ◽  
Reduced Graphene

A green method to synthesize the reduced graphene oxide using supercritical fluid has been developed, which is an environmentally friendly and efficient route. The reduced graphene oxide has been examined by X-ray diffraction, Raman spectroscopy. We have also studied the effects of reduction temperatures and supercritical fluids on the electrical properties of reduced graphene oxide. It was found that ethanol has higher reducing capability than CO2at all temperatures (200 - 400°C) examined in this study for graphene oxide reduction. As a result, reduced graphene oxide (6300 S/m) from supercritical ethanol treatment has 5 times as high conductivity as that from supercritical CO2treatment at the reduction temperature of 400°C. This green process is applicable for large scale production of reduced graphene oxides for various practical applications.

Photo-induced reduction of biomass-derived 5-hydroxymethylfurfural using graphitic carbon nitride supported metal catalysts

RSC Advances ◽  
2016 ◽  
Vol 6 (104) ◽  
pp. 101968-101973 ◽  
Author(s):  
Yuanyuan Guo ◽  
Jinzhu Chen
Keyword(s):  
Transition Metal ◽  
Carbon Nitride ◽  
Metal Catalysts ◽  
Transition Metal Catalysts ◽  
Graphitic Carbon ◽  
Graphitic Carbon Nitride ◽  
Supported Metal Catalysts ◽  
Supported Metal

Photo-induced reduction of biomass-derived 5-hydroxymethylfurfural was achieved by using graphitic carbon nitride-supported transition metal catalysts.

Simple approach for large-scale production of reduced graphene oxide films

2014 ◽  
Vol 243 ◽  
pp. 340-346 ◽  
Author(s):  
Ming Zhang ◽  
Bin Gao ◽  
Diana C. Vanegas ◽  
Eric S. McLamore ◽  
June Fang ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Large Scale ◽  
Oxide Films ◽  
Simple Approach ◽  
Scale Production ◽  
Large Scale Production ◽  
Reduced Graphene

scholarly journals A Facile Method for Batch Preparation of Electrochemically Reduced Graphene Oxide

Nanomaterials ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 376 ◽  
Author(s):  
Yi-Fang Hung ◽  
Chia Cheng ◽  
Chun-Kai Huang ◽  
Chii-Rong Yang
Keyword(s):  
Graphene Oxide ◽  
Electrochemical Reduction ◽  
Photoelectron Spectroscopy ◽  
Large Scale ◽  
Reduction Technique ◽  
Chemical Agent ◽  
Scale Production ◽  
Large Scale Production ◽  
Electrochemically Reduced Graphene Oxide ◽  
Π Stacking Interaction

The electrochemical reduction of graphene oxide (GO) is an environmentally friendly and energy-saving method for improving the characteristics of GO. However, GO films must be coated on the cathode electrode in advance when usingthis technique. Thus, the formed electrochemically reduced GO (ERGO) films can be used only as sensing or conductive materials in devices because mass production of the flakes is not possible. Therefore, this study proposes a facile electrochemical reduction technique. In this technique, GO flakes can be directly used as reduced materials, and no GO films are required in advance. A 0.1 M phosphate buffered saline solution was used as the electrolyte, which is a highly safe chemical agent. Experimental results revealed that the as-prepared GO flakes were electrochemically reduced to form ERGO flakes by using a −10 V bias for 8 h. The ratio of the D-band and G-band feature peaks was increased from 0.86 to 1.12, as revealed by Raman spectroscopy, the π-π stacking interaction operating between the ERGO and GO has been revealed by UV-Vis absorption spectroscopy, and the C–O ratio was increased from 2.02 to 2.56, as indicated by X-ray photoelectron spectroscopy. The electrical conductivity of the ERGO film (3.83 × 10−1 S·cm−1) was considerably better than that of the GO film (7.92 × 10−4 S·cm−1). These results demonstrate that the proposed electrochemical reduction technique can provide high-quality ERGO flakes and that it has potential for large-scale production.

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