XPS studies on Ba, BaO and the oxidation of Ba

Verhoeven, J.; Doveren, H. van

doi:10.1016/0378-5963(80)90101-4

Cited by 73 publications

(19 citation statements)

References 19 publications

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“…The Ba 4d 3/2 and Ba 4d 5/2 peaks for the fresh powder are observed at 92.80 and 90.25 eV, respectively (Figure a). After electrode preparation, which involved dispersing the clathrate powder into an aqueous slurry with carbon black and carboxymethyl cellulose (CMC) binder followed by coating onto Cu foil and heating, the Ba peaks shifted to slightly lower binding energies and a shoulder appeared at lower binding energies (Figure b), which is consistent with the formation of Ba oxides that have lower binding energies than metallic Ba . The Si 2p unresolved doublet is centered at about 98.5 eV, corresponding to the Si in the clathrate framework.…”

Section: Resultsmentioning

confidence: 72%

“…After electrode preparation, which involved dispersing the clathrate powder into an aqueous slurry with carbon black and carboxymethyl cellulose (CMC) binder followed by coating onto Cu foil and heating, the Ba peaks shifted to slightly lower binding energies and a shoulder appeared at lower binding energies (Figure 8 b), which is consistent with the formation of Ba oxides that have lower binding energies than metallic Ba. [55][56][57] The Si 2p unresolved doublet is centered at about 98.5 eV, corresponding to the Si in the clathrate framework. Compared with regular c-Si, which has a binding energy at about 99.5 eV for Si-Si, the shift of the Si 2p peak to lower binding energies is possibly due to the interaction of the clathrate Si with Ba and Al, which are more electropositive.…”

Section: Xps Characterization After Cyclingmentioning

confidence: 99%

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Type I Clathrates as Novel Silicon Anodes: An Electrochemical and Structural Investigation

Raghavan

Wagner

et al. 2015

Advanced Science

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Silicon clathrates contain cage‐like structures that can encapsulate various guest atoms or molecules. An electrochemical evaluation of type I silicon clathrates based on Ba8AlySi46−y as the anode material for lithium‐ion batteries is presented here. Postcycling characterization with nuclear magnetic resonance and X‐ray diffraction shows no discernible structural or volume changes even after electrochemical insertion of 44 Li (≈1 Li/Si) into the clathrate structure. The observed properties are in stark contrast with lithiation of other silicon anodes, which become amorphous and suffer from large volume changes. The electrochemical reactions are proposed to occur as single phase reactions at approximately 0.2 and 0.4 V versus Li/Li+ during lithiation and delithiation, respectively, distinct from diamond cubic or amorphous silicon anodes. Reversible capacities as high as 499 mAh g−1 at a 5 mA g−1 rate were observed for silicon clathrate with composition Ba8Al8.54Si37.46, corresponding to ≈1.18 Li/Si. These results show that silicon clathrates could be promising durable anodes for lithium‐ion batteries.

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Section: Resultsmentioning

confidence: 72%

Section: Xps Characterization After Cyclingmentioning

confidence: 99%

Type I Clathrates as Novel Silicon Anodes: An Electrochemical and Structural Investigation

Raghavan

Wagner

et al. 2015

Advanced Science

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“…The Gauss type shape as well as the binding energy value indicated that BaO layer evolved on the tungsten surface [16]. Looking at the XPS spectrum of W4f peak, two bonding states could be at once distinguished: elemental and oxidized W. The doublet of the elemental W appears at 30,5 eV/32,65 eV, and that of the oxidized W appears at 35,1 eV/37,25 eV.…”

Section: Resultsmentioning

confidence: 95%

Investigation of evolved layer structure of Ba-containing emission materials

Beck

Josepovits

Sneider³

2007

Per. Pol. Chem. Eng.

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The emission material in High Intensity Discharge (HID) lamps plays a significant role in lowering the electrode work function and thus the lamps' operating temperature. Bacontaining rare earth-and alkali earth tungstate materials are commonly used as cathode thermionic emission materials because of the production of high intensity discharge.The goal of this present work is to model a cathode tip surface evolved during sintering and to compare the physical and chemical properties of emission materials currently used in the industry. In order to achieve this goal, we investigated and compared the layer structure of Ba-Ca-and Ba-Y-containing emission materials evolved on polycrystalline tungsten foils. Simultaneously, the tendency of the work function was also monitored as a function of Ba/BaO layer thickness. The Ba coverage of cathode is one of the most important factors during the lifetime of HID lamps. The initial Ba diffusion was also examined. We also proposed a layer model, valuable for the structures occurring during the operation of lamps.The chemical composition of the flat samples was analysed by X-ray Photoelectron Spectroscopy (XPS) and the electron emission properties by Work Function Spectroscopy (WFS).

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“…Moreover, the intensity of the O1s spectra for all samples is observed to decrease with increasing BaF 2 content, which is in good agreement with the survey spectra, thereby indicating the improved quality with BaF 2 content. The bonding states of oxygen atoms were confirmed by the deconvolution of the Ba3d spectra ( Figure S1c), which depicted the presence of α (779.8-781.3 eV) and β (795.1-798.8 eV) couplings of barium oxide [61,62]. Lack of component peaks corresponding to bonding states such as Ba-N [63] is suggestive that the Ba atoms remain bonded to oxygen atoms to form the stable oxide form outside the hBN domains, thereby, having no impact on the overall structure of hBN nanosheets.…”

Section: Raman and Ft-ir Analysismentioning

confidence: 81%

Improving Formation Conditions and Properties of hBN Nanosheets Through BaF2-assisted Polymer Derived Ceramics (PDCs) Technique

et al. 2020

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Hexagonal boron nitrite (hBN) is an attractive material for many applications such as in electronics as a complement to graphene, in anti-oxidation coatings, light emitters, etc. However, the synthesis of high-quality hBN at cost-effective conditions is still a great challenge. Thus, this work reports on the synthesis of large-area and crystalline hBN nanosheets via the modified polymer derived ceramics (PDCs) process. The addition of both the BaF2 and Li3N, as melting-point reduction and crystallization agents, respectively, led to the production of hBN powders with excellent physicochemical properties at relatively low temperatures and atmospheric pressure conditions. For instance, XRD, Raman, and XPS data revealed improved crystallinity and quality at a decreased formation temperature of 1200 °C upon the addition of 5 wt% of BaF2. Moreover, morphological determination illustrated the formation of multi-layered nanocrystalline and well-defined shaped hBN powders with crystal sizes of 2.74–8.41 ± 0.71 µm in diameter. Despite the compromised thermal stability, as shown by the ease of oxidation at high temperatures, this work paves way for the production of large-scale and high-quality hBN crystals at a relatively low temperature and atmospheric pressure conditions.

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XPS studies on Ba, BaO and the oxidation of Ba

Cited by 73 publications

References 19 publications

Type I Clathrates as Novel Silicon Anodes: An Electrochemical and Structural Investigation

Type I Clathrates as Novel Silicon Anodes: An Electrochemical and Structural Investigation

Investigation of evolved layer structure of Ba-containing emission materials

Improving Formation Conditions and Properties of hBN Nanosheets Through BaF2-assisted Polymer Derived Ceramics (PDCs) Technique

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