Composites of Palladium–Nickel Alloy Nanoparticles and Graphene Oxide for the Knoevenagel Condensation of Aldehydes with Malononitrile
Authors: Hakan Burhan
Esra Kuyuldar
Nabih Lolak
Süleyman Akocak
Haydar Goksu
Fatih Sen
Journal: ACS Omega (2019)
Discipline: CHEMISTRY
Keywords: Palladium-nickel nanoparticles; Graphene oxide; Nanocatalyst; Knoevenagel reaction; Characterization
Affiliations: Department of Pharmaceutical Chemistry, Faculty of Pharmacy, Adiyaman University, 02040 Adiyaman, Turkey, Sen Research Group, Department of Biochemistry, Faculty of Arts and Science, Dumlupınar University, Evliya Çelebi Campus, 43100 Kütahya, Turkey, Kaynasli Vocational College, Duzce University, 81900 Düzce, Turkey

Abstract:  Herein, we have described uniformly dispersed palladium-nickel nanoparticles furnished on graphene oxide (GO-supported PdNi nanoparticles) as a powerful heterogeneous nanocatalyst for the promotion of Knoevenagel reaction between malononitrile and aromatic aldehydes under mild reaction conditions. The successful characterization of PdNi nanoparticles on the GO surface was shown by X-ray diffraction, X-ray photoelectron spectroscopy, high-resolution transmission electron microscopy (HR-TEM), and TEM. GO-supported PdNi nanoparticles, which are used as highly efficient, stable, and durable catalysts, were used for the first time for the Knoevenagel condensation reaction. The data obtained here showed that the GO-supported PdNi nanocatalyst had a unique catalytic activity and demonstrated that it could be reused five times without a significant decrease in the catalytic performance. The use of this nanocatalyst results in a very short reaction time under mild reaction conditions, high recyclability, excellent catalytic activity, and a straightforward work-up procedure for Knoevenagel condensation of malononitrile and aromatic aldehydes. 

Retracted: No

PubPeer comments:
 Figure 2. XRD patterns of GO-supported PdNi NPs and Pd@GO NPs. Similarity in some fragments of XRD patterns. ![file] , 
 This paper is one of at least 30 papers by the same research group that all share the same photo. In all papers, this photo is used as a zoomed-in inset representing the high-resolution transmission electron microscopy (HRTEM) analysis of the  atomic lattice fringe and particle size of the nanoparticles. Of concern, the same photo is used to represent a different type of nanoparticle in each of these papers. Here is a collage of 6 different uses of the same photo,  Inset 1 : ![file] Here is a list of the 30 papers identified so far that all use this photo, and the different types of nanoparticles that they represent. * Aysenur Aygun et al. - DOI: 10.1016 j.jpba.2019.112961 - Nigella sativa Pt * Aysun Su0327avk et al. - DOI: 10.1016 j.molliq.2019.112355 - PtNi@AC * Aysun Su0327avk et al. - DOI: 10.1016 j.msec.2019.01.113 - ZnNi@f-MWCNT * Aysun Su0327avk et al. - DOI: 10.1038 s41598-019-55746-y - PdNi@rGO * Betuu0308l Su0327en et al. - DOI: 10.1016 j.ijhydene.2018.03.175 - Pd@GO * Betuu0308l Su0327en et al. - DOI: 10.1016 j.nanoso.2017.08.013 - PdRu@GO * Betuu0308l Su0327en et al. - DOI: 10.1016 j.apcatb.2017.11.067 - RhPt TC@GO * Betuu0308l Su0327en et al. - DOI: 10.1016 j.ijhydene.2018.07.081 - Pd-Ir@AC * Betuu0308l Su0327en et al. - DOI: 10.1016 j.jcis.2018.05.021 - Ru-Ni@PVP * Betuu0308l Su0327en et al. - DOI: 10.1016 j.nanoso.2018.07.008 - Pd@AC * Betuu0308l Su0327en et al. - DOI: 10.1016 j.ijhydene.2018.07.122 - PdRuNi@GO * Betuu0308l Su0327en et al. - DOI: 10.1016 j.ijhydene.2019.01.215 - PdCo@GO * Betuu0308l Su0327en et al. - DOI: 10.1016 j.jtice.2019.04.040 - PdNi@VC * Betuu0308l Su0327en et al. - DOI: 10.1016 j.ijhydene.2018.12.051 - PdCo@MOF * Betuu0308l Su0327en et al. - DOI: 10.1016 j.ijhydene.2019.02.176 - RuCu@rGO * Birguu0308tay Su0327ahin et al. - DOI: 10.1016 j.colsurfb.2017.12.042 - Pt * Buse Demirkan et al. - DOI: 10.1038 s41598-020-59935-y - rGO Pd@PPy * Buse Demirkan et al. - DOI: 10.1038 s41598-019-48802-0 - Pt-Co@rGO * Fatma Diler et al. - DOI: 10.1016 j.molliq.2019.111967 - Pd@GO * Hayriye Genc Bilgicli et al. - DOI: 10.1016 j.micromeso.2020.110014 - CPG * Hilal Acidereli et al. - DOI: 10.1016 j.renene.2020.07.105 - PdRu@G * Mehmet Salih Nas et al. - DOI: 10.1016 j.molliq.2019.112100 - Pt-Co@GO * Nabih Lolak et al. - DOI: 10.1021 acsomega.9b00485 - PdNi@GO * Oznur Alptekin et al. - DOI: 10.1039 D0CY00641F - PtRh@GO * Rukiye Ayranci et al. - DOI: 10.1016 j.msec.2019.02.040 - Pt Ni@rGO * Sait Bozkurt et al. - DOI: 10.1016 j.aca.2017.07.051 - Pd TNM@rGO * Sinan Eris et al. - DOI: 10.1016 j.jcis.2017.11.085 - Pt@f-CB * Sinan Eris et al. - DOI: 10.1016 j.ijhydene.2017.11.063 - Pt@f-VC * Suat Tacu0327yu0131ldu0131z et al. - DOI: 10.1016 j.molliq.2019.04.019 - Ru-Rh@PVP * Zeynep Dasu0327delen et al. - DOI: 10.1016 j.apcatb.2017.08.014 - Pt@GO-PVP Here is Figure 1 of this paper: ![file] , 
 Correction, October 2020, found here: https: pubs.acs.org doi 10.1021 acsomega.0c04383  *Figures 1 and 2 and Table 2 were corrected as shown.* ![file] Of particular note, as pointed out in comment #1, this was a Type III duplication, where parts of a plot appear to have been manipulated. I am not sure if a Correction fully addresses the concerns readers might have about this paper. ,