RETRACTED ARTICLE: Revisiting the Evolution of
         IR Spectra of CO Adsorbed on Au Nanoparticles Supported on Non-reducible
         Supports

Atwi, Ranin; Elgayyar, Taha; Aires, F.J. Cadete Santos; Tuel, A.; Meunier, Frédéric

doi:10.1007/s11244-020-01372-2

Cited by 4 publications

(12 citation statements)

References 56 publications

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“…Due to the lower frequency compared to CO adsorption on metallic Au (usually above 2100 cm –1 ), the CO adsorption bands at 2090–1900 cm –1 on Au nanoparticles are widely attributed to CO adsorption on negatively charged Au. − ,,,− It is assumed that negatively charged Au could be formed via electron transfer from reducible oxide supports to Au nanoparticles after reduction treatment. However, the 2090–1900 cm –1 bands appear not only on reducible oxide-supported Au nanoparticles but also on nonreducible oxide-supported Au nanoparticles. ,, CO adsorption bands on Au nanoparticles at such low frequencies are rarely seen in surface science studies, neither in our study of CO adsorption on Au/SiO 2 nanoparticles with highly pure CO used. In some model studies, CO adsorption on electron-rich Au shows a CO adsorption band at lower frequencies compared to CO on neutrally charged Au, ,, but it is not at such low frequencies (<2090 cm –1 ), usually a small red shift by just several wavenumbers.…”

Section: Discussionmentioning

confidence: 55%

“…Figure a shows the PM-IRRAS results of CO adsorption on 5 MLE Au/SiO 2 /Mo(110) with CO adsorption pressure ranging from 0.5 to 100 Torr. The average Au nanoparticle size is estimated to be about 2–5 nm at this Au coverage . A CO adsorption band is observed at 2118 cm –1 on Au/SiO 2 in 0.5 Torr CO. With increasing CO adsorption pressure, the CO adsorption peak increases in intensity and shifts to lower vibration frequencies.…”

Section: Resultsmentioning

confidence: 86%

“…After carefully examining the literature results, several common features can be obtained about the CO adsorption bands on supported Au nanoparticles at 2090–1900 cm –1 at elevated pressures: (i) The CO adsorption bands at 2090–1900 cm –1 only show up with CO adsorption pressure above certain values. , (ii) The CO adsorption bands at 2090–1900 cm –1 can be observed or enhanced after long-time CO exposure or annealing the supported Au nanoparticles in the CO gas. ,,,, (iii) The CO adsorption bands at 2090–1900 cm –1 only appear in the CO or reducing environment without O 2 . Introduction of O 2 in the adsorption system will result in a decrease or extinction of the adsorption bands, which is usually interpreted as the oxidation of negatively charged Au. ,,,,,, (iv) The CO adsorption bands at 2090–1900 cm –1 are thermally stable on Au surfaces at room temperature even after the CO gas is evacuated. After pumping down to UHV conditions, usually a CO band at around 2040 cm –1 is observed. , It is surprising to see the high thermal stability of the adsorbed CO.…”

Section: Discussionmentioning

confidence: 97%

“…Panayotov et al argued that it is impossible that anionic Au exists on their oxidized Au/TiO 2 samples, and they attributed the CO adsorption band at around 2080 cm –1 to CO adsorption on low-coordinated metallic Au sites . It has also been proposed that the CO adsorption bands at 2090–1900 cm –1 on Au nanoparticles may be related to the restructuring of Au surfaces rather than CO adsorption on negatively charged gold species. ,,, No conclusions, so far, could interpret all of the features associated with the CO adsorption bands on Au nanoparticles at 2090–1900 cm –1 .…”

Section: Discussionmentioning

confidence: 99%

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In Situ PM-IRRAS Study of CO Adsorption on Au Surfaces: Solving the Puzzle

et al. 2021

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Infrared spectra have been widely used to study CO adsorption and reaction on Au surfaces to reveal the underlying reaction mechanism. However, the results and interpretation of IR spectra of CO adsorption on Au surfaces remain highly controversial, which prevents reliable conclusions from earlier studies. Herein, we studied CO adsorption on Au thin films and nanoparticles by in situ polarization modulation infrared reflection absorption spectroscopy (PM-IRRAS) with highly purified CO. Only a single CO adsorption feature above 2100 cm −1 is observed on Au nanoparticles and thin films with CO adsorption pressure varying from 1 × 10 −6 to 100 Torr. This observation contradicts the general findings that CO adsorption on Au surfaces at elevated CO pressures shows strong adsorption bands at 2090−1900 cm −1 mostly assigned to CO bound to negatively charged Au. We rule out the contradiction is caused by the pressure gap between vacuum and elevated pressure conditions employed for CO adsorption. We provide clear evidence that the CO adsorption bands in the region of 2090−1900 cm −1 , widely observed in earlier studies of high-pressure CO adsorption on Au surfaces, are actually caused by Ni-carbonyl (Ni(CO) 4 ) contamination from incompletely purified CO gas rather than CO adsorption on negatively charged Au. Ni-carbonyl can be adsorbed and decomposed on Au surfaces, resulting in the formation of NiAu bimetallic alloys. We further investigate CO adsorption behaviors on bimetallic NiAu thin films and nanoparticles by in situ PM-IRRAS. We find that Au is enriched on the NiAu surface under vacuum conditions, while Ni is segregated on the surface under elevated CO pressure conditions. The strong CO adsorption on Ni sites on NiAu bimetallic surfaces leads to an atop CO adsorption band at 2090−2040 cm −1 , while CO bound on Au sites yields an adsorption band above 2100 cm −1 . Our study clearly clarifies the origin of the widely reported CO adsorption bands at 2090−1900 cm −1 and resolves the puzzle of IR spectra of CO on Au surfaces, thus providing an important paradigm that complete purification of CO gas is a prerequisite for any in situ studies associated with CO at elevated pressures.

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Section: Discussionmentioning

confidence: 55%

Section: Resultsmentioning

confidence: 86%

Section: Discussionmentioning

confidence: 97%

Section: Discussionmentioning

confidence: 99%

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In Situ PM-IRRAS Study of CO Adsorption on Au Surfaces: Solving the Puzzle

et al. 2021

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“…In the previous work [33], a 13 atoms model was applied to reveal the essence of electronic effect on Au-Pt bimetallic catalyst, however, which is quite different with nanoparticles. adsorption on kinks at ～2070 cm −1 was not observed [64] on catalyst Au 100 /MCF, which is probably due to the strong interaction between Au NPs and silica support [29] or low CO adsorption temperature (25 o C). As shown in Fig.…”

Section: Catalysts Characterizationmentioning

confidence: 89%

Mesostructured cellular foam silica supported Au–Pt nanoalloy: Enrichment of d-state electrons for promoting the catalytic synergy

Liu

Cao

et al. 2021

Microporous and Mesoporous Materials

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A mesostructured cellular foam (MCF) silica was applied to support gold (Au)platinum (Pt) alloy nanoparticles (NPs) for benzyl alcohol partial oxidation. A catalytic synergy on bimetallic gold (Au)-platinum (Pt) nanoparticle (NP) catalyst, referring to that introducing Au to Pt leading to a higher catalytic performance has been observed. However, the essence of this synergistic effect is still under debate. In this work, a series of MCF supported Au-Pt NP catalysts are designed to reveal the essence. Well-developed porous structure of MCF support eliminated the mass transfer limitation and intrinsic catalytic activity was obtained.The improved catalytic performance on bimetallic catalyst is attributed to the geometric and electronic changes of active sites after formation of Au-Pt alloy NPs.Compared with monometallic catalyst, the formation of Au-Pt alloy results in the changes of particle size and lattice structure. Electronic property analyses confirmed the increase of d state electrons on Au-Pt alloy NPs, which are calculated from s-p-d hybridization and intra-atomic charge redistribution, leading to the increased abundance of transferable d electrons near Fermi level and further enhancing the catalytic activity. These findings gain new insights into the catalytic synergy of bimetallic nanoparticles and shed light on the optimization of these catalysts.

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In situ formation of Ni(CO)₄ contaminant during IR analyses using a metal-containing reaction cell

Meunier

2022

Catal. Sci. Technol.

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RETRACTED ARTICLE: Revisiting the Evolution of IR Spectra of CO Adsorbed on Au Nanoparticles Supported on Non-reducible Supports

Cited by 4 publications

References 56 publications

In Situ PM-IRRAS Study of CO Adsorption on Au Surfaces: Solving the Puzzle

In Situ PM-IRRAS Study of CO Adsorption on Au Surfaces: Solving the Puzzle

Mesostructured cellular foam silica supported Au–Pt nanoalloy: Enrichment of d-state electrons for promoting the catalytic synergy

In situ formation of Ni(CO)₄ contaminant during IR analyses using a metal-containing reaction cell

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RETRACTED ARTICLE: Revisiting the Evolution of IR Spectra of CO Adsorbed on Au Nanoparticles Supported on Non-reducible Supports

Cited by 4 publications

References 56 publications

In Situ PM-IRRAS Study of CO Adsorption on Au Surfaces: Solving the Puzzle

In Situ PM-IRRAS Study of CO Adsorption on Au Surfaces: Solving the Puzzle

Mesostructured cellular foam silica supported Au–Pt nanoalloy: Enrichment of d-state electrons for promoting the catalytic synergy

In situ formation of Ni(CO)4 contaminant during IR analyses using a metal-containing reaction cell

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In situ formation of Ni(CO)₄ contaminant during IR analyses using a metal-containing reaction cell