Chemistry of Aerogels and Their Applications

Pierre, Alain C.; Pajonk, G.M.

doi:10.1021/cr0101306

Cited by 1,913 publications

(1,352 citation statements)

References 213 publications

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“…The solution is then heated (100 -140 ºC) for several days and the resulting product is nano-titanium dioxide. 16,18 TiO bulk + 2Cl + C → TiCl + CO/CO (2.1)…”

Section: Sol-gelmentioning

confidence: 99%

Explosibility of micron- and nano-size titanium powders

Boilard

Amyotte

Khan

et al. 2013

Journal of Loss Prevention in the Process Industries

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“…The solution is then heated (100 -140 ºC) for several days and the resulting product is nano-titanium dioxide. 16,18 TiO bulk + 2Cl + C → TiCl + CO/CO (2.1)…”

Section: Sol-gelmentioning

confidence: 99%

Explosibility of micron- and nano-size titanium powders

Boilard

Amyotte

Khan

et al. 2013

Journal of Loss Prevention in the Process Industries

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“…[42][43][44][45][46][47][48][49][50][51] However, they are almost inactive towards the ORR in PEM fuel cells. In this paper, a nitrogen-doped carbon xerogel (N-CX) was developed by incorporating nitrogen into the carbon xerogel and employed as an electrocatalyst for ORR in PEM fuel cells.…”

mentioning

confidence: 99%

Nitrogen-doped carbon xerogel: A novel carbon-based electrocatalyst for oxygen reduction reaction in proton exchange membrane (PEM) fuel cells

Jin

Zhang

Zhong

et al. 2011

Energy Environ. Sci.

173

117

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A low-cost, novel carbon-based electrocatalyst for oxygen reduction reaction (ORR), nitrogen-doped carbon xerogel (N-CX) was synthesized via a sol-gel polymerization method followed by a pyrolysis process. The N-CX catalyst exhibited a high activity for ORR, and a good stability in acid media. A high performance with a maximum power density of 360 mW cm À2 was achieved on a single PEM fuel cell with N-CX as the cathode electrocatalyst.As one of the key materials of PEM fuel cells, the electrocatalyst for oxygen reduction reaction (ORR) in particular plays a critical role in determining cell performance, cost and durability. The platinumbased carbon-supported electrocatalysts (e.g. Pt/C) have been considered as the most effective elecrocatalysts for ORR in PEM fuel cells due to their high activities and good stabilities. 1-9 However, the issues of high cost, scarce sources and long-term durability limit their large-scale production and hinder the commercialization of PEM fuel cells. [10][11][12][13][14] In order to decrease the cost of electrocatalysts and eliminate their dependence on noble metals, various non-noble metal catalysts have been explored recently as alternatives to the Pt-based electrocatalysts, which include chalcogenide catalysts, 15-19 transition metal macrocyclic compounds, 20-22 transition metallic oxides 23-27 and carbon-based catalysts. [28][29][30][31][32][33][34][35] In particular, carbon-based catalysts doped with the heteroatoms such as nitrogen (N) or boron (B) have been paid much attention and been proposed as typical non-noble metal catalysts for ORR 36-38 in alkaline media. Especially, since Gong et al. 37 reported the superior activity and stability of nitrogen doped carbon nanotube in alkaline solution, the heteroatom doped carbon materials have been expected to be promising alternative Pt-based catalysts. The doped carbon-based catalysts demonstrate tailored physico-chemical properties, such as structure, electrical conductivity, surface properties and oxidation stability, depending on the amount of the incorporated heteroatoms. It is also reported that the incorporated heteroatoms in the carbon structure contribute to the catalytic activities for many reactions 39-41 including the ORR in alkaline media. However, the activities and stabilities of these catalysts in acidic media are still challenging.Recently, carbon xerogels have been reported as the electrode materials for capacitors and electrocatalyst supports because of their controllable structures, high electronic conductivities, good anticorrosion properties, facile preparations and low costs. 42-51 However, they are almost inactive towards the ORR in PEM fuel cells. In this paper, a nitrogen-doped carbon xerogel (N-CX) was developed by incorporating nitrogen into the carbon xerogel and employed as an electrocatalyst for ORR in PEM fuel cells. Broader contextDue to their advantages such as fast response, high efficiency, environmental friendliness, etc., PEM fuel cells are considered as the most promising power sources for t...

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“…Hence they have received broad attention from multi‐disciplined researchers and are widely used in many fields 1, 2, 3. Aerogels are normally prepared from the sol–gel chemistry and followed special drying process (e.g., supercritical drying or freeze drying) 2.…”

mentioning

confidence: 99%