High-temperature piezoresistive C / SiOC sensors

Roth, F.; Schmerbauch, Christoph; Ionescu, Emanuel; Nicoloso, N.; Guillon, Olivier; Riedel, Ralf

doi:10.5194/jsss-4-133-2015

Cited by 21 publications

(21 citation statements)

References 17 publications

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“…The ID/IG ratio of Co/NiOC and Ni/SiOC was calculated to be 1.01 and 1.04 respectively which indicates the ordering of segregated carbon during pyrolysis. The ceramic samples even show a peak around 2720 cm −1 corresponding to second‐order vibration modes of the D band (2D) and at 2900 cm −1 attributed to carbon disorder (D+G) within the ceramic matrix …”

Section: Resultsmentioning

confidence: 99%

“…The ceramic samples even show a peak around 2720 cm À 1 corresponding to second-order vibration modes of the D band (2D) and at 2900 cm À 1 attributed to carbon disorder (D + G) within the ceramic matrix. [43,44] The transmission electron microscope (TEM) images of ceramic structure projects rock structured monolithic pieces wherein the existence of two interpenetrating amorphous phases of SiOC and disordered graphitic carbon structures ( Figure S2, Supporting Information). [23] Figure 2 a-c shows FES-EM and TEM images of Co/SiOC, which confirmed that intermetallic cobalt silicide nanoparticles are in a contiguous position to the SiOC matrix.…”

Section: Resultsmentioning

confidence: 99%

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Metal Silicide Nanosphere Decorated Carbon‐Rich Polymer‐Derived Ceramics: Bifunctional Electrocatalysts towards Oxygen and their Application in Anion Exchange Membrane Fuel Cells

et al. 2019

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The current hindrance in the commercialization of electrochemical devices such as fuel cells and metal–air batteries is the high cost and poor stability of widely employed noble‐metal‐based electrocatalysts. In this report, a new intermetallic nickel/cobalt silicide‐decorated carbon‐rich silica‐based ceramic composites (Co/SiOC or Ni/SiOC) were successfully synthesized as alternative bifunctional electrocatalysts. The oxygen reduction reaction (ORR) and the oxygen evolution reaction (OER) kinetics of the prepared composite materials were evaluated by electrochemical characterization. Co/SiOC exhibited more positive ORR kinetics with the onset potential of 0.87 V vs. RHE compared to that of Ni/SiOC, which is slightly lower compared to Pt/C. Conversely, Ni/SiOC exhibits a 50 mV more positive OER onset potential compared to Co/SiOC with almost similar OER kinetics to RuO2. The bifunctional ability concluded that Ni/SiOC was a good bifunctional catalyst with an oxygen electrode potential 0.89 V. As Co/SiOC performs as a better ORR catalyst, it was utilized as a cathode catalyst for the construction of anion exchange membrane fuel cell and its fuel cell performance was evaluated. The Co/SiOC composites produce a peak power density of 54 mW/cm2, representing a satisfactory result when compared with Pt/C. The results reveal that the intermetallic nickel/cobalt silicide nanosphere decorated ceramic materials can have a promising future as efficient alternative electrocatalysts in electrochemical devices.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Metal Silicide Nanosphere Decorated Carbon‐Rich Polymer‐Derived Ceramics: Bifunctional Electrocatalysts towards Oxygen and their Application in Anion Exchange Membrane Fuel Cells

et al. 2019

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“…The lateral size L a of non-distorted/ideally crystallized graphite can be estimated from Raman measurements with visible light (514 nm) yielding domain sizes of¯2 nm, which remain almost constant within the temperature range 14001600°C. 39) Combining these data with our UV Raman results, the state of carbon or stage of graphitization at T = 1600°C, respectively, can be best described by turbostratic carbon.…”

Section: ¹1mentioning

confidence: 99%

UV Raman spectroscopy of segregated carbon in silicon oxycarbides

Roth

Waleska

Heß

et al. 2016

J. Ceram. Soc. Japan

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Polymer-derived silicon oxycarbides exhibiting¯1 and 10 vol.% of segregated carbon finely dispersed within a glassy Si x O y C z matrix have been investigated by UV Raman spectroscopy using a laser excitation of 4.8 eV ( = 256.7 nm). Carbon exists as amorphous sp 2 sp 3 bonded component in SiOC/C (¯1 vol.%) pyrolyzed at 1100°C in H 2 , including CC single bonds, polymeric chains and small polycyclic aromatic hydrocarbons (PAHs). The formation of nanocrystalline carbon at T > 1400°C is seen in the Raman spectra of SiOC/C (¯1 vol.%) and SiOC/C (10 vol.%) by the appearance of the G band of graphite. Tempering at 1600°C increases the degree of order within the carbon phase. However, the slight narrowing of the G peak with processing temperature (by about 5%) indicates still not well-crystallized carbon: the Raman results can be best explained by turbostratic carbon (with a lateral size L a of µ2 nm) and do not support the model description in literature as a network of single layer graphene.

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“…Further, two minor peaks corresponding to the n 3 bond (1200 cm À1 ) and n 1 bond (1500 cm À1 ) of polyolenic chains in the SiOC may be integrated into the aromatic domains by, e.g., a Diels-Alder reaction. 26,34 The intensity ratio of the D and G bands (i.e. I G /I D ratio) helps to estimate the defects of the composite ceramics.…”

Section: Macrostructure and Surface Characteristicsmentioning

confidence: 99%