scholarly journals Asphaltene oxide promotes a broad range of synthetic transformations

2019 ◽  
Vol 2 (1) ◽  
Author(s):  
Hyosic Jung ◽  
Christopher W. Bielawski
Keyword(s):  
Graphene Oxide ◽  
Elevated Temperatures ◽  
Petroleum Refining ◽  
Explosive Decomposition ◽  
Active Materials ◽  
New Class ◽  
Microwave Reactors ◽  
Catalytically Active ◽  
Polycyclic Aromatic ◽  
Synthetic Transformations

Abstract Carbocatalysts, which are catalytically-active materials derived from carbon-rich sources, are attractive alternatives to metal-based analogs. Graphene oxide is a prototypical example and has been successfully employed in a broad range of synthetic transformations. However, its use is accompanied by a number of practical and fundamental drawbacks. For example, graphene oxide undergoes explosive decomposition when subjected to elevated temperatures or microwaves. We found that asphaltene oxide, an oxidized collection of polycyclic aromatic hydrocarbons that are often discarded from petroleum refining processes, effectively overcomes the drawbacks of using graphene oxide in synthetic chemistry and constitutes a new class of carbocatalysts. Here we show that asphaltene oxide may be used to promote a broad range of transformations, including Claisen-Schmidt condensations, C–C cross-couplings, and Fischer indole syntheses, as well as chemical reactions which benefit from the use of microwave reactors.

scholarly journals Dual role of CO in the stability of subnano Pt clusters at the Fe3O4(001) surface

2016 ◽  
Vol 113 (32) ◽  
pp. 8921-8926 ◽  
Author(s):  
Roland Bliem ◽  
Jessi E. S. van der Hoeven ◽  
Jan Hulva ◽  
Jiri Pavelec ◽  
Oscar Gamba ◽  
...  
Keyword(s):  
Density Functional ◽  
Elevated Temperatures ◽  
Time Lapse ◽  
Dual Role ◽  
Oxidation Catalyst ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Active Metal ◽  
Catalytically Active ◽  
The Stability

Interactions between catalytically active metal particles and reactant gases depend strongly on the particle size, particularly in the subnanometer regime where the addition of just one atom can induce substantial changes in stability, morphology, and reactivity. Here, time-lapse scanning tunneling microscopy (STM) and density functional theory (DFT)-based calculations are used to study how CO exposure affects the stability of Pt adatoms and subnano clusters at the Fe3O4(001) surface, a model CO oxidation catalyst. The results reveal that CO plays a dual role: first, it induces mobility among otherwise stable Pt adatoms through the formation of Pt carbonyls (Pt1–CO), leading to agglomeration into subnano clusters. Second, the presence of the CO stabilizes the smallest clusters against decay at room temperature, significantly modifying the growth kinetics. At elevated temperatures, CO desorption results in a partial redispersion and recovery of the Pt adatom phase.

Graphene quantum dots supported by graphene oxide as a sensitive fluorescence nanosensor for cytochrome c detection and intracellular imaging

2017 ◽  
Vol 5 (31) ◽  
pp. 6300-6306 ◽  
Author(s):  
Lin Cao ◽  
Xiangqing Li ◽  
Lixia Qin ◽  
Shi-Zhao Kang ◽  
Guodong Li
Keyword(s):  
Quantum Dots ◽  
Graphene Oxide ◽  
Cytochrome C ◽  
Graphene Quantum Dots ◽  
A549 Cells ◽  
High Sensitivity ◽  
Fluorescence Sensor ◽  
Intracellular Imaging ◽  
New Class ◽  
Sensitivity And Selectivity

A new class of Cyt c detection fluorescence sensor based on graphene quantum dots supported by graphene oxide has been facilely developed. The sensor shows a high sensitivity and selectivity for Cyt c detection, and further exhibits favorable intracellular imaging in A549 cells.

An effective approach for modifying carbonaceous materials with niobium single sites to improve their catalytic properties

2015 ◽  
Vol 44 (46) ◽  
pp. 19956-19965 ◽  
Author(s):  
A. S. Bozzi ◽  
R. L. Lavall ◽  
T. E. Souza ◽  
M. C. Pereira ◽  
P. P. de Souza ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Graphene Oxide ◽  
Activated Carbon ◽  
Carbon Materials ◽  
Catalytic Properties ◽  
Carbonaceous Materials ◽  
Simple Route ◽  
Catalytically Active

In this paper we show a very simple route for the incorporation of catalytically active niobium species on the surface of carbon materials, such as graphene oxide, carbon nanotubes and activated carbon.

Thionation reactions of 2-pyrrole carboxylates

RSC Advances ◽  
2016 ◽  
Vol 6 (74) ◽  
pp. 69691-69697 ◽  
Author(s):  
Brandon R. Groves ◽  
Deborah A. Smithen ◽  
T. Stanley Cameron ◽  
Alison Thompson
Keyword(s):  
Elevated Temperatures ◽  
Lawesson’S Reagent ◽  
New Class ◽  
Lawesson's Reagent

Reaction of 2-pyrrole carboxylates with Lawesson's reagent at elevated temperatures results in the corresponding thionoesters, concurrent with the production of a new class of pyrrole annulated with the (1,3,2)-thiazaphospholidine unit.

scholarly journals Catalytic synergy effect of MoS2/reduced graphene oxide hybrids for a highly efficient hydrogen evolution reaction

RSC Advances ◽  
2017 ◽  
Vol 7 (9) ◽  
pp. 5480-5487 ◽  
Author(s):  
Jung Eun Lee ◽  
Jaemin Jung ◽  
Taeg Yeoung Ko ◽  
Sujin Kim ◽  
Seong-Il Kim ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Hydrogen Evolution ◽  
Hydrogen Evolution Reaction ◽  
Electronic Transition ◽  
Catalytic Performance ◽  
Synergy Effect ◽  
Tafel Slope ◽  
Reduced Graphene ◽  
Catalytically Active

GO content tuning gradually enhanced the HER catalytic performance of the MoS2/rGO hybrids, decreasing the Tafel slope from 82 to 48 mV per decade owing to an increase of catalytically active areas and an electronic transition of MoS2.

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