scholarly journals The role of dissolution in the synthesis of high-activity organic nanocatalysts in a wet chemical reaction

2017 ◽  
Vol 5 (17) ◽  
pp. 8029-8036 ◽  
Author(s):  
L. J. Liu ◽  
Y. D. Lai ◽  
H. H. Li ◽  
L. T. Kang ◽  
J. J. Liu ◽  
...  

By combining nucleation/growth with dissolution of nanocrystals in a simple wet chemical reaction without capping agent under ambient conditions, a high-activity organic nano-photocatalyst (ZnTPP·H2O) was synthesized by simply adjusting the reaction time.

2019 ◽  
Author(s):  
Je-Ruei Wen ◽  
Benjamin Roman ◽  
Freddy Rodriguez Ortiz ◽  
Noel Mireles Villegas ◽  
Nicholas Porcellino ◽  
...  

Lack of detailed understanding of the growth mechanism of CsPbBr3 nanocrystals has hindered sophisticated morphological and chemical control of this important emerging optoelectronic material. Here, we have elucidated the growth mechanism by slowing the reaction kinetics. When 1-bromohexane is used as an alternative halide source, bromide is slowly released into the reaction mixture, extending the reaction time from ~3 seconds to greater than 20 minutes. This enables us to monitor the phase evolution of products over the course of reaction, revealing that CsBr is the initial species formed, followed by Cs4PbBr6, and finally CsPbBr3. Further, formation of monodisperse CsBr nanocrystals is demonstrated in a bromide-deficient and lead-abundant solution. The CsBr can only be transformed into CsPbBr3 nanocubes if additional bromide is added. Our results indicate a fundamentally different growth mechanism for CsPbBr3 in comparison with more established semiconductor nanocrystal systems and reveal the critical role of the chemical availability of bromide for the growth reactions.<br>


2021 ◽  
Vol 55 (4) ◽  
pp. 2628-2638
Author(s):  
Zhen Cao ◽  
Hao Li ◽  
Gregory V. Lowry ◽  
Xiaoyang Shi ◽  
Xiangcheng Pan ◽  
...  

2006 ◽  
Vol 258-260 ◽  
pp. 63-67
Author(s):  
V.M. Chumarev ◽  
V.P. Maryevich ◽  
V.A. Shashmurin

Diffusion processes play a dominant part in the macro kinetics of Fe, Ni and Co oxidation by calcium and sodium sulfates. Here, the reaction product forms a compact covering which spatially divides the reagents on the surface in the same way as in the oxidation and sulfidization of metals by oxygen and sulfur. Therefore, it is possible to assume in advance that interaction of metals with calcium and sodium sulfates will be determined not by the actual chemical reaction properly but by the diffusion transport processes.


2014 ◽  
Vol 24 (7) ◽  
pp. 727-753 ◽  
Author(s):  
Myoungsun Suh ◽  
Hyoungeun Moon ◽  
Heesup Han ◽  
Sunny Ham
Keyword(s):  

2018 ◽  
Vol 4 (12) ◽  
pp. eaau9366 ◽  
Author(s):  
J. J. Navarro ◽  
M. Pisarra ◽  
B. Nieto-Ortega ◽  
J. Villalva ◽  
C. G. Ayani ◽  
...  

Carbon deposits are well-known inhibitors of transition metal catalysts. In contrast to this undesirable behavior, here we show that epitaxial graphene grown on Ru(0001) promotes the reversible formation of a C–C bond between −CH2CN and 7,7,8,8-tetracyano-p-quinodimethane (TCNQ). The catalytic role of graphene is multifaceted: First, it allows for an efficient charge transfer between the surface and the reactants, thus favoring changes in carbon hybridization; second, it holds the reactants in place and makes them reactive. The reaction is fully reversible by injecting electrons with an STM tip on the empty molecular orbitals of the product. The making and breaking of the C–C bond is accompanied by the switching off and on of a Kondo resonance, so that the system can be viewed as a reversible magnetic switch controlled by a chemical reaction.


1981 ◽  
Vol 52 (10) ◽  
pp. 6025-6031 ◽  
Author(s):  
M. Iino ◽  
H. Yano ◽  
Y. Takubo ◽  
M. Shimazu
Keyword(s):  

2004 ◽  
Vol 77 (5) ◽  
pp. 891-913 ◽  
Author(s):  
Pankaj Y. Patil ◽  
William J. van Ooij

Abstract Adhesion between rubber and brass-coated steel cords is enhanced by using resins as adhesion promoters. Experiments were carried out using a squalene liquid rubber modeling approach to study the effect of resins on the chemistry of the vulcanization reaction. The formation of new intermediates during vulcanization and changes in chemical concentrations with reaction time was studied using Gel Permeation Chromatography (GPC) analysis of the reacted squalene mixtures. Also, the effect of presence of resins on the surface of sulfidized brass cords was studied by analyzing the adhesion layer's elemental composition using the Electron Dispersive X-ray Spectroscopy (EDX) and Secondary Ion Mass Spectrometry (SIMS) characterization techniques. The changes in surface morphology of the adhesion layer with reaction time was noted by taking micrographs using the Scanning Electron Microscopy (SEM) technique. In this paper, a new mechanism is proposed for the role of resins in the improvement of initial and aged adhesion performance between rubber and brass-coated steel tire cords.


2013 ◽  
Vol 38 (1) ◽  
pp. 45-48
Author(s):  
Kouichi Nakashima ◽  
Ichiro Fujii ◽  
Satoshi Wada

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