Chemical Modification of B4C Films and B4C/Pd Layers Stored in Different Environments

Feng, Yufei; Qi, Runze; Jiang, Li; Huang, Qiushi; Li, Tongzhou; Liu, Genchang; Li, Wenbin; Yan, Wensheng; Zhang, Zhong; Wang, Zhanshan

doi:10.3390/ma14051319

Cited by 16 publications

(7 citation statements)

References 57 publications

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“…When the oxygen concentration is lower in the vacuum chamber, the vanadium oxidates work as a catalyst, which promotes the combination of boron and oxygen, but in the higher oxygen concentration environment, boron will "rob" the majority of oxygen atoms, which prevents the oxidation state of vanadium oxide toward its highest oxidation state. Besides the NiV/B 4 C multilayers, a similar catalysis has been found in the Pd/ B 4 C multilayers [27]. Due to the catalysis, the ultrathin Pd/B 4 C multilayers degraded rapidly when stored in air.…”

Section: Discussionsupporting

confidence: 57%

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Background Pressure Induced Structural and Chemical Change in NiV/B4C Multilayers Prepared by Magnetron Sputtering

et al. 2022

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NiV/B4C multilayers with a small d-spacing are suitable for multilayer monochromator working at a photon energy region from 5 to 8 keV, or photon energy region from 10 to 100 keV. To investigate the influence of background pressure during fabrication, NiV/B4C multilayers with a d-spacing of 3.0 nm were fabricated by magnetron sputtering with different background pressures. The grazing incidence x-ray reflectivity (GIXR) and transmission electron microscopy (TEM) measurement illustrated the structural change that happened in NiV/B4C multilayers when background pressure is high. The electron dispersive x-ray spectroscopy (EDX) of NiV/B4C multilayer deposited with a high background pressure suggests a gradient distribution of oxygen, which corresponds to the gradient thickness change. The detailed x-ray absorption near edge spectroscopy (XANES) comparison of NiV/B4C multilayers, NiV coating, and B4C coating showed the chemical state change induced by background pressure. We concluded that during the deposition, vanadium oxide promoted the oxidation of boron. In order to fabricate a good performance of NiV/B4C multilayers, the background pressure needs lower than 1 × 10−4 Pa.

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Section: Discussionsupporting

confidence: 57%

“…An energy range from 100 to 1,000 eV was used with an energy resolution of approximately 0.2 eV. All XANES spectra were measured using the process of normalization by considering the low and high photon energy parts of the spectra far from the threshold [26,27].…”

Section: Methodsmentioning

confidence: 99%

Background Pressure Induced Structural and Chemical Change in NiV/B4C Multilayers Prepared by Magnetron Sputtering

et al. 2022

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“…[ 21 ] The features in the high‐energy regime of 195–205 eV are due to the transition of B 1s electrons to the unoccupied B σ* states. [ 22 ] The C K‐edge X‐ray absorption near‐edge structure spectra were measured to analyze the change of local atomic structure around the carbon element. As shown in Figure 3f, the C 1s absorption edge of the B/NC NS was characterized by the CB bonds from 291 to 298 eV.…”

Section: Resultsmentioning

confidence: 99%

Controllable Exfoliation of MOF‐Derived Van Der Waals Superstructure into Ultrathin 2D B/N Co‐Doped Porous Carbon Nanosheets: A Superior Catalyst for Ambient Ammonia Electrosynthesis

Yan

Zhao

Zhang

et al. 2023

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The electrocatalytic nitrogen reduction reaction (NRR) to synthesize NH3 under ambient conditions is a promising alternative route to the conventional Haber–Bosch process, but it is still a great challenge to develop electrocatalysts’ high Faraday efficiency and ammonia yield. Herein, a facile and efficient exfoliation strategy to synthesize ultrathin 2D boron and nitrogen co‐doped porous carbon nanosheets (B/NC NS) via a metal–organic framework (MOF)‐derived van der Waals superstructure, is reported. The results of experiments and theoretical calculations show that the doping of boron and nitrogen can modulate the electronic structure of the adjacent carbon atoms; which thus, promotes the competitive adsorption of nitrogen and reduces the energy required for ammonia synthesis. The B/NC NS exhibits excellent catalytic performance and stability in electrocatalytic NRR, with a yield rate of 153.4 µg·h−1·mg−1 cat and a Faraday efficiency of 33.1%, which is better than most of the reported NRR electrocatalysts. The ammonia yield of B/NC NS can maintain 92.7% of the initial NRR activity after 48 h stability test. The authors’ controllable exfoliation strategy using MOF‐derived van der Waals superstructure can provide a new insight for the synthesis of other 2D materials.

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“…5(b) where it is obvious that the dip is prominent in the boron case and shifts towards higher energy for boron carbide. In the literature the reported K-edge value of bulk boron is 188 eV (Henke et al, 1993) whereas for stoichiometric B 4 C the reported value of the edge lies in the 189-191.6 eV range (Jime ´nez et al, 1999;Feng et al, 2021). In X-ray absorption measurements performed on boron-rich carbide film (B 11 C), Jimenez et al (1999) observed the boron K-edge at 187 eV.…”

Section: Figurementioning

confidence: 99%

Study of interface reaction in a B₄C/Cr mirror at elevated temperature using soft X-ray reflectivity

Modi¹,

Gupta²,

Yadav³

et al. 2022

J Synchrotron Radiat

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Boron carbide is a prominent material for high-brilliance synchrotron optics as it remains stable up to very high temperatures. The present study shows a significant change taking place at 550°C in the buried interface region formed between the Cr adhesive layer and the native oxide layer present on the silicon substrate. An in situ annealing study is carried out at the Indus-1 Reflectivity beamline from room temperature to 550°C (100°C steps). The studied sample is a mirror-like boron carbide thin film of 400 Å thickness deposited with an adhesive layer of 20 Å Cr on a silicon substrate. The corresponding changes in the film structure are recorded using angle-dependent soft X-ray reflectivity measurements carried out in the region of the boron K-edge after each annealing temperature. Analyses performed using the Parratt recursive formalism reveal that the top boron carbide layer remains intact but interface reactions take place in the buried Cr–SiO2 region. After 300°C the Cr layer diffuses towards the substrate. At higher temperatures of 500°C and 550°C the Cr reacts with the native oxide layer and tends to form a low-density compound of chromium oxysilicide (CrSiO x ). Depth profiling of Si and Cr distributions obtained from secondary ion mass spectroscopy measurements corroborate the layer model obtained from the soft X-ray reflectivity analyses. Details of the interface reaction taking place near the substrate region of boron carbide/Cr sample are discussed.

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Chemical Modification of B4C Films and B4C/Pd Layers Stored in Different Environments

Cited by 16 publications

References 57 publications

Background Pressure Induced Structural and Chemical Change in NiV/B4C Multilayers Prepared by Magnetron Sputtering

Background Pressure Induced Structural and Chemical Change in NiV/B4C Multilayers Prepared by Magnetron Sputtering

Controllable Exfoliation of MOF‐Derived Van Der Waals Superstructure into Ultrathin 2D B/N Co‐Doped Porous Carbon Nanosheets: A Superior Catalyst for Ambient Ammonia Electrosynthesis

Study of interface reaction in a B₄C/Cr mirror at elevated temperature using soft X-ray reflectivity

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Chemical Modification of B4C Films and B4C/Pd Layers Stored in Different Environments

Cited by 16 publications

References 57 publications

Background Pressure Induced Structural and Chemical Change in NiV/B4C Multilayers Prepared by Magnetron Sputtering

Background Pressure Induced Structural and Chemical Change in NiV/B4C Multilayers Prepared by Magnetron Sputtering

Controllable Exfoliation of MOF‐Derived Van Der Waals Superstructure into Ultrathin 2D B/N Co‐Doped Porous Carbon Nanosheets: A Superior Catalyst for Ambient Ammonia Electrosynthesis

Study of interface reaction in a B4C/Cr mirror at elevated temperature using soft X-ray reflectivity

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Study of interface reaction in a B₄C/Cr mirror at elevated temperature using soft X-ray reflectivity