Use of silica-based homogeneously distributed gold nickel nanohybrid as a stable nanocatalyst for the hydrogen production from the dimethylamine borane
Authors: Aysun Savk
Sibel Demiroglu Mustafov
Umran Ercetin
Betul Sen
Mehmet Ferdi Fellah
Oznur Alptekin
Fatih Sen
Journal: Scientific Reports (2020)
Discipline: Multidisciplinary
Keywords: silica-based; gold-nickel; nanohybrid; hydrogen production; dimethylamine borane
Affiliations: Department of Mechanical Engineering, Faculty of Engineering, Dumlupƒ±nar University, Evliya √áelebi Campus, 43100, K√ºtahya, Turkey., Sen Research Group, Department of Biochemistry, Faculty of Art and Science, Dumlupƒ±nar University, Evliya √áelebi Campus, 43100, K√ºtahya, Turkey., Department of Mechanical Engineering, Faculty of Engineering, Dumlupƒ±nar University, Evliya √áelebi Campus, 43100, K√ºtahya, Turkey. ., Department of Chemical Engineering, Bursa Technical University, Mimar Sinan Campus, 16310, Bursa, Turkey., Sen Research Group, Department of Biochemistry, Faculty of Art and Science, Dumlupƒ±nar University, Evliya √áelebi Campus, 43100, K√ºtahya, Turkey. .

Abstract:  In this study, the effects of silica-based gold-nickel (AuNi@SiO2) nanohybrid to the production of hydrogen from dimethylamine borane (DMAB) were investigated. AuNi@SiO2 nanohybrid constructs were prepared as nanocatalysts for the dimethylamine borane dehydrogenation. The prepared nanohybrid structures were exhibited high catalytic activity and a stable form. The resulting nanohybrid, AuNi@SiO2 as a nanocatalyst, was tested in the hydrogen evolution from DMAB at room temperature. The synthesized nanohybrids were characterized using some analytical techniques. According to the results of the characterization, it was observed that the catalyst was in nanoscale and the gold-nickel alloys showed a homogenous distribution on the SiO2 surface. After characterization, the turn over frequency (TOF) of nanohybrid prepared for the production of hydrogen from dimethylamine was calculated (546.9 h-1). Also, the prepared nanohybrid can be used non-observed a significant decrease in activity even after the fifth use, in the same reaction. In addition, the activation energy (Ea) of the reaction of DMAB catalyzed AuNi@SiO2 nanohybrid was found to be 16.653 ¬± 1 kJmol-1 that facilitated the catalytic reaction. Furthermore, DFT-B3LYP calculations were used on the AuNi@SiO2 cluster to investigate catalyst activity. Computational results based on DFT obtained in the theoretical part of the study support the experimental data. 

Retracted: No

PubPeer comments:
 Figure 2. XRD patterns of Au@SiO2 and AuNi@SiO2 nanohybrid. Vertical scaling and shift along horizontal axis and two parts of XRD patterns become very similar.  , 
 Thanks for your interest. I have asked original files, if related person does not give a original files, then I will apply for correction. I am so sorry for the case. Thanks again... , 
 This phenomenon is very easy to understand. If they used the same glass slide when preparing XRD test samples, and at the same time they had fewer samples, this phenomenon would appear. The background peak has no value. The main XRD peaks of the three samples are completely different, and this result is acceptable. According to this low-resolution picture, it is impossible to tell whether the two spectra overlap , 
 I agree with #1 Thallarcha Lechrioleuca ; the noise peaks look much more similar than expected.  The background peak has no value is incorrect here. It tells us that the figure as shown in the paper shows unexpectedly similar graphs. Also, let s discuss Figure 1. This paper is one of 40+ (41 and counting) 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 :  A list of the first 30 papers that all use this photo, and the different types of nanoparticles that they represent can e.g. be found here: * Betuu0308l Su0327en et al. - DOI: 10.1016 j.ijhydene.2018.03.175 - https: pubpeer.com publications 8AD71F4A32472314CCE9983D47E36F Of note, this is a different set of papers than the 15 papers by the same group that all appear to use another HRTEM image called  Inset 2 . For an example of that photo and the list of the first 14 papers identified in that set, see DOI: 10.1016 j.ijhydene.2017.05.113 https: pubpeer.com publications CAD2F16435F6C639F5DE6851A2E61D Here is Figure 1 of this paper, which includes the  Inset 1 photo:  , 
 #3  If they used the same glass slide when preparing XRD test samples, and at the same time they had fewer samples, this phenomenon would appear . You seem to be arguing that the test samples produce no background x-ray scattering between the main peaks, so all the background noise is produced by a glass slide, and is completely reproducible. Is that a fair summary? , 
 #3 Additional to the comment #5 by Hoya Camphorifolia, I very much dispute your comment  The background peak has no value. . The base line of a measurement is influenced by too many factors to be relevant data, yes. But exactly this chaotic interaction makes the chance of having the same base line scientifically implausible. Two measurements of the same sample with the same machine under the same conditions should give the same looking diagram overall, but zooming into it more closely will reveal a different base line  zigzag . , 
 #6 As you said, the background peak is affected by many factors, So it does not give any valuable information. This is why in many articles, the XRD background peaks are completely subtracted or smoothed out. I have a question, how can I tell if two completely different XRD spectra are not from the same sample tested twice? Similar samples will also give the same looking diagram overalluff0cand zooming into it more closely will also reveal a different baseline  zigzag . , 
 #7 Check comment here: https: pubpeer.com publications 39F7A3E772552294D3AC69E147D447#20 Even if you record the same sample 3 times, noise is always different. It is random  gaussian noise. , 
 #7 I m not sure if I understand you correctly, but let me try to answer your question:  how can I tell if two completely different XRD spectra are not from the same sample tested twice?  Do you mean that Person A measured Sample B two times and somehow got two completely different XRD spectra from that two measurements. Then they present those 2 XRD spectra in the paper as belonging to 2 different samples (lets say C D), while in truth it came from one sample? If that is your question then the answer is easy: You can t. If you obtain 2 different XRD spectra from the same sample, then either your device is broken or you have in fact, not the same sample. Maybe it reacted in the mean time or it was not in fact a homogenous sample and in the second measurement you scanned a different part of the sample. The linked comment from #8 nicely shows what i meant. You see there the same overall looking lines with similar features at e.g. 20u00b0, 21.5u00b0 and 25.5u00b0, which could mean that there are small refraction peaks there. Only longer measurements could prove that. But appart from those features, the rest of the base line ist simply not similar. And there are definitely no repeating features, as would be expected from normal measurements. ,