Preparation of carbon nanospheres by non-catalytic chemical vapor deposition and their formation mechanism

Zhang, You; Yang, Wei; Luo, Ruiying; Shang, Hai-dong

doi:10.1016/s1872-5805(16)60025-2

Cited by 15 publications

(7 citation statements)

References 24 publications

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“…Also, the porosity of NCMs leads to increase effective surface area and accessible active sites to electrolyte to accelerate mass transfer processes during electrochemical ORR 13 – 17 . For increasing active sites and porosity in NCMs, lots of preparation methods have been introduced such as chemical vapor deposition 18 , 19 , laser-induced pyrolysis 20 , arc-discharge 21 , and template-based growth 22 which are involving with complicated and expensive instrumentation, critical atmosphere control and limited production. Also, they are suffering from unnecessary high cost and time-consuming approach 23 .…”

Section: Introductionmentioning

confidence: 99%

Nitrogen-rich graphitic-carbon@graphene as a metal-free electrocatalyst for oxygen reduction reaction

Begum

Ahmed

Kim

2020

Sci Rep

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the metal-free nitrogen-doped graphitic-carbon@graphene (ng-c@G) is prepared from a composite of polyaniline and graphene by a facile polymerization following by pyrolysis for electrochemical oxygen reduction reaction (oRR). pyrolysis creates a sponge-like with ant-cave-architecture in the polyaniline derived nitrogenous graphitic-carbon on graphene. the nitrogenous carbon is highly graphitized and most of the nitrogen atoms are in graphitic and pyridinic forms with less oxygenated is found when pyrolyzed at 800 °C. The electrocatalytic activity of Ng-C@G-800 is even better than the benchmarked Pt/C catalyst resulting in the higher half-wave potential (8 mV) and limiting current density (0.74 mA cm −2) for oRR in alkaline medium. Higher catalytic performance is originated from the special porous structure at microscale level and the abundant graphitic-and pyridinic-n active sites at the nanoscale level on carbon-graphene matrix which are beneficial to the high O 2-mass transportation to those accessible sites. Also, it possesses a higher cycle stability resulting in the negligible potential shift and slight oxidation of pyridinic-n with better tolerance to the methanol. To save the world from day-by-day increasing energy demands and environmental concerns, the clean, highly efficient and renewable energy technologies are immediately required to be implemented 1. Among various renewable energy technologies, fuel cells (FCs) and metal-air batteries are regarded as the promising clean energy sources because of their high energy conversion efficiency and emission-free power generation 2,3. However, the efficiency of those technologies is strongly depend on the reaction kinetics which are involving with 4. For example, the sluggish kinetics of cathodic oxygen reduction reaction (ORR) hinders the overall performance of FCs 5. Thus, FCs require a highly active and durable electrocatalysts for increasing ORR kinetics. Although, Pt-based materials have been used as the state-of-the-art electrocatalysts for ORR because of their higher current density with lower overpotential compared to other electrocatalysts 6,7 , but their poor durability and prohibitive cost are hampering widespread usage of FCs technology in practical life 6,7. In recent past, researchers are focusing on nitrogen-doped carbon materials (NCMs) with various extrabeneficial features as metal-free ORR catalysts which shown to be an efficient, durable and carbon monoxide (CO)-poisoning-free substitute to Pt-based catalysts 4,8-10. Although, the previous research has shown that the significant improvement has done for ORR catalysis on NCMs, still the ORR performance needs to be improved 11. There are two important approaches are strongly correlated to the improvement of the ORR electrocatalytic activity of NCMs. One is to enhance the intrinsic activity of doped nitrogen and the other one is to increase the number of active sites 4. For enhancing the intrinsic activity of NCMs, they should be engineered to contain a high number of active sites with better exp...

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Section: Introductionmentioning

confidence: 99%

Nitrogen-rich graphitic-carbon@graphene as a metal-free electrocatalyst for oxygen reduction reaction

Begum

Ahmed

Kim

2020

Sci Rep

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“…This concentric texture has been observed with TEM and shows that carbon nanospheres are composed of graphitic layers with unclosed graphitic flakes on their surfaces [45,46]. Carbon nanospheres are also generally observed as an agglomeration of carbon spheres with varying diameters [45,47,48,49,50]. The coalescence and accretion of carbon nanospheres was observed by Nieto-Marquez et al via a catalytic growth method [49], Kang and Wang via catalytic carbonization after treatment in acetone [45], and by Jin et al via the pyrolysis of a variety of hydrocarbons in the absence of a catalyst [48].…”

Section: Resultsmentioning

confidence: 75%

Utilizing a Single Silica Nanospring as an Insulating Support to Characterize the Electrical Transport and Morphology of Nanocrystalline Graphite

et al. 2019

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A graphitic carbon, referred to as graphite from the University of Idaho thermolyzed asphalt reaction (GUITAR), was coated in silica nanosprings and silicon substrates via the pyrolysis of commercial roofing tar at 800 °C in an inert atmosphere. Scanning electron microscopy and transmission electron microscopy images indicate that GUITAR is an agglomeration of carbon nanospheres formed by the accretion of graphitic flakes into a ~100 nm layer. Raman spectroscopic analyses, in conjunction with scanning electron microscopy and transmission electron microscopy, indicate that GUITAR has a nanocrystalline structure consisting of ~1–5 nm graphitic flakes interconnected by amorphous sp3 bonded carbon. The electrical resistivities of 11 single GUITAR-coated nanospring devices were measured over a temperature range of 10–80 °C. The average resistivity of all 11 devices at 20 °C was 4.3 ± 1.3 × 10−3 Ω m. The GUITAR coated nanospring devices exhibited an average negative temperature coefficient of resistivity at 20 °C of −0.0017 ± 0.00044 °C−1, which is consistent with the properties of nanocrystalline graphite.

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“…Carbon spheres have been widely researched and applied to various fields-including batteries, photocatalysis, capacitors, and fuel cells-due to their easily available sources and facile synthesis. The last few decades have witnessed a rapid growth in sustainable energy field and this has led to the research of various application and approaches of carbon spheres, including carbonization routes [29], chemical vapor deposition (CVD) [30], ultrasonic-spray [31], and hydrothermal carbonization (HTC) [6,32,33]. Among these methods, hydrothermal carbonization is the one that aroused the greatest interest due to its facile procedure and mild experimental condition.…”

Section: Carbon Sphere Template-overview Of Synthesismentioning

confidence: 99%

Carbon Sphere Template Derived Hollow Nanostructure for Photocatalysis and Gas Sensing

Wang

Qin

et al. 2020

Nanomaterials

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As a green and preferred technology for energy crisis and environmental issues, continuous research on photocatalysis and gas sensing has come forth at an explosive rate. Thus far, promising synthetic methods have enabled various designs and preparations of semiconductor-based nanostructure which have shown superior activity. This review summarized various synthetic routines toward carbon sphere template derived hollow nanostructures and their successful attempts in synthesize doping, solid solution, heterostructure, and surface modified nanostructures for heterogeneous photocatalysis and gas sensing. Moreover, the challenges and future prospects are briefly discussed. It is eagerly anticipated that this review may broaden the view and in-depth understanding of carbon sphere template derived hollow nanostructures while expected to have further progresses in heterogeneous photocatalysis, gas sensing and other related fields which will make great contributions to their application.

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Preparation of carbon nanospheres by non-catalytic chemical vapor deposition and their formation mechanism

Cited by 15 publications

References 24 publications

Nitrogen-rich graphitic-carbon@graphene as a metal-free electrocatalyst for oxygen reduction reaction

Nitrogen-rich graphitic-carbon@graphene as a metal-free electrocatalyst for oxygen reduction reaction

Utilizing a Single Silica Nanospring as an Insulating Support to Characterize the Electrical Transport and Morphology of Nanocrystalline Graphite

Carbon Sphere Template Derived Hollow Nanostructure for Photocatalysis and Gas Sensing

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