Monodisperse Ag/Pd core/shell nanoparticles assembled on reduced graphene oxide as highly efficient catalysts for the transfer hydrogenation of nitroarenes
Authors: Kıvılcım Şendil
Önder Metin
Hasan Can
Mehmet Serdar Gültekin
Journal: Journal of Colloid and Interface Science (2017)
Discipline: CHEMISTRY
Keywords: Core/shell nanoparticles; Nitroarenes reduction; Reduced graphene oxide; Silver-palladium; Transfer hydrogenation.
Affiliations: Department of Chemistry, Faculty of Science, Atatürk University, 25240 Erzurum, Turkey; East Anatolian High Technology Research and Application Center (DAYTAM), Atatürk University, 25240 Erzurum, Turkey. Electronic address: ., Department of Chemistry, Faculty of Science, Atatürk University, 25240 Erzurum, Turkey; East Anatolian High Technology Research and Application Center (DAYTAM), Atatürk University, 25240 Erzurum, Turkey., Department of Chemistry, Faculty of Science, Atatürk University, 25240 Erzurum, Turkey; Department of Chemistry, Kafkas University, Faculty of Arts and Sciences, Kars 36100, Turkey., Department of Chemistry, Faculty of Science, Atatürk University, 25240 Erzurum, Turkey. Electronic address: .

Abstract:  Addressed herein is a facile seed-mediated synthesis of Ag/Pd core/shell nanoparticles (NPs) and their assembly on reduced graphene oxide (rGO) to catalyze the transfer hydrogenation of nitroarenes to anilines using ammonia borane (AB) as a hydrogen donor under ambient conditions. Monodisperse Ag/Pd core/shell NPs with controllable Pd shell-thickness were synthesized by the means of thermal decomposition of palladium(II) bromide over as-prepared Ag NPs in the mixture of oleylamine and oleic acid at 220°C. As-synthesized Ag/Pd core/shell NPs were characterized by TEM, HR-TEM, XRD, XPS, UV-Vis spectroscopy and ICP-MS and then they were assembled on reduced graphene oxide (rGO). Next, rGO@Ag/Pd catalysts were tested in the transfer hydrogenation of nitroarenes in which ammonia borane (AB) was used as a hydrogen donor at room temperature. It was demonstrated that the thickness of the Pd shell has a significant effect on the catalytic activity of rGO@Ag/Pd catalysts and the 1.75nm Pd shell provided the highest performance in the transfer hydrogenation reactions. The rGO@Ag/Pd catalyzed transfer hydrogenation reactions were tested over a variety of nitroarenes (total 16 examples) and they were all converted to the corresponding aniline derivatives with high yields in 5-15min under ambient conditions. 

Retracted: No

PubPeer comments:
 Exactly same XPS survey data used in two different articles without any reference to each other, but the high resolution spectra of the core levels are peculiarly different. ![file] , 
 Thanks for pointing out this issue. We examined two XPS survey spectra and concluded that they look similar at first glance, but they are not same. There are differences in the noises and peak positions as well as the overall spectra. Moreover, the high-resolution XPS spectra for Pd3d and Ag3d core-levels are quite different in terms of both peak positions and the peak shapes. Considering these two materials included the same atoms (Ag, Pd, C, N, O), Ag and Pd based nanoparticles deposited on the same support material (rGO), and the scanning of the XPS survey spectra for a wide-range binding energy (0-1250 eV), obtaining similar XPS survey spectra is possible, because XPS survey spectra gives qualitative information about the surface atoms of the material. It is only used for the qualitative analysis of the elements on the surface of materials. However, the presented high-resolution XPS spectra for Pd3d and Ag3d core-levels are quite different, indicating two different XPS analysis were conducted on the samples. On the other hand, as a research group, we have access to XPS instrument in our university. When we give a sample for the XPS analysis, we always ask for getting the XPS survey spectra as well as the high-resolution XPS spectra for the related elements. In this regard, having high-resolution XPS data for the related elements without the XPS survey spectrum for a sample is not possible for our research group. Since the represented high-resolution XPS spectra for Ag and Pd core-levels are highly different, it clearly indicates that two different XPS analysis were conducted on the samples. Therefore, the presented XPS survey spectra are not same, but they just look like similar. We can share the raw data with you if you request them via sending a message to us from an academic email address. , 
 a close look on the noise and background below 200 eV and above 600 eV shows that the survey data is the same in two articles, contrary to the similarity argument of the author. , 
 To #3 if you think that my explanations is contrary to yours, I can share the raw data with you if you send me an email from an academic email. Because I do not want to discuss this issue with anonymous persons herein. Thanks for your understanding. , 
 Dear Dr. Metin, I agree with the comments in #1 and #3, that these two plots look very similar to each other. Could you please post high resolution images of these plots here? I am not an anonymous person :-) ,