Highly Active Heterogeneous 3 nm Gold Nanoparticles on Mesoporous Carbon as Catalysts for Low-Temperature Selective Oxidation and Reduction in Water

ACS Catalysis ◽  
2015 ◽  
Vol 5 (2) ◽  
pp. 797-802 ◽  
Author(s):  
Shuai Wang ◽  
Jie Wang ◽  
Qingfei Zhao ◽  
Dandan Li ◽  
Jian-Qiang Wang ◽  
...  
RSC Advances ◽  
2015 ◽  
Vol 5 (77) ◽  
pp. 62732-62738 ◽  
Author(s):  
Yu-Xin Miao ◽  
Li-Hui Ren ◽  
Lei Shi ◽  
Wen-Cui Li

One active Au/MnO2 catalysts were prepared by a colloidal deposition method. The deactivation was studied by temperature programmed desorption of CO2 analysis.


2019 ◽  
Author(s):  
Raghu Nath Dhital ◽  
keigo nomura ◽  
Yoshinori Sato ◽  
Setsiri Haesuwannakij ◽  
Masahiro Ehara ◽  
...  

Carbon-Fluorine (C-F) bonds are considered the most inert organic functionality and their selective transformation under mild conditions remains challenging. Herein, we report a highly active Pt-Pd nanoalloy as a robust catalyst for the transformation of C-F bonds into C-H bonds at low temperature, a reaction that often required harsh conditions. The alloying of Pt with Pd is crucial to activate C-F bond. The reaction profile kinetics revealed that the major source of hydrogen in the defluorinated product is the alcoholic proton of 2-propanol, and the rate-determining step is the reduction of the metal upon transfer of the <i>beta</i>-H from 2-propanol. DFT calculations elucidated that the key step is the selective oxidative addition of the O-H bond of 2-propanol to a Pd center prior to C-F bond activation at a Pt site, which crucially reduces the activation energy of the C-F bond. Therefore, both Pt and Pd work independently but synergistically to promote the overall reaction


Catalysts ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 641
Author(s):  
Lukasz Wolski ◽  
Grzegorz Nowaczyk ◽  
Stefan Jurga ◽  
Maria Ziolek

The aim of the study was to establish the influence of a co-precipitation agent (i.e., NaOH–immediate precipitation; hexamethylenetetramine/urea–gradual precipitation and growth of nanostructures) on the properties and catalytic activity of as-synthesized Au-CeO2 nanocomposites. All catalysts were fully characterized with the use of XRD, nitrogen physisorption, ICP-OES, SEM, HR-TEM, UV-vis, XPS, and tested in low-temperature oxidation of benzyl alcohol as a model oxidation reaction. The results obtained in this study indicated that the type of co-precipitation agent has a significant impact on the growth of gold species. Immediate co-precipitation of Au-CeO2 nanostructures with the use of NaOH allowed obtainment of considerably smaller and more homogeneous in size gold nanoparticles than those formed by gradual co-precipitation and growth of Au-CeO2 nanostructures in the presence of hexamethylenetetramine or urea. In the catalytic tests, it was established that the key factor promoting high activity in low-temperature oxidation of benzyl alcohol was size of gold nanoparticles. The highest conversion of the alcohol was observed for the catalyst containing the smallest Au particle size (i.e., Au-CeO2 nanocomposite prepared with the use of NaOH as a co-precipitation agent).


2014 ◽  
Vol 147 ◽  
pp. 132-143 ◽  
Author(s):  
R.V. Gulyaev ◽  
E.M. Slavinskaya ◽  
S.A. Novopashin ◽  
D.V. Smovzh ◽  
A.V. Zaikovskii ◽  
...  

Sign in / Sign up

Export Citation Format

Share Document