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Anhydrous

About: Anhydrous is a research topic. Over the lifetime, 17632 publications have been published within this topic receiving 163495 citations.


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TL;DR: In this paper, a sulfonic acid-based covalent organic framework (TpPa-SO3H) was synthesized that exhibits intrinsic proton conductivity under anhydrous conditions.
Abstract: A sulfonic-acid-based covalent organic framework (TpPa-SO3H) has been synthesized that exhibits intrinsic proton conductivity under anhydrous conditions. The sulfonic acid groups are aligned on the two-dimensional (2D) layers at periodic intervals and promote the proton hopping inside the hexagonal one-dimensional channel. The intrinsic proton conductivity of TpPa-SO3H was measured as 1.7 × 10–5 S cm–1 at 120 °C under anhydrous conditions. To enhance the proton conductivity, we have synthesized a hybrid COF TpPa-(SO3H-Py) by a ligand-based solid-solution approach that contains sulfonic acid as the acidic site, as well as pyridine as the basic site, in order to immobilize acidic proton carrier molecules. Impregnation of phytic acid molecules inside the framework increases the anhydrous proton conductivity up to 5 × 10–4 S cm–1 at 120 °C. Such an approach highlights the advantage and first-time use of hybrid COF for interplaying intrinsic to extrinsic proton conductivity.

268 citations

Journal ArticleDOI
TL;DR: In this paper, the atomic structure of RuO2·xH2O as a function of water content from x = 0.84 to 0.02 using X-ray diffraction and atomic pair density function (PDF).
Abstract: Hydrous ruthenium oxide (RuO2·xH2O or RuOxHy) is a mixed proton−electron conductor which could be used in fuel cells and ultracapacitors. Its charge-storage (pseudocapacitance) and electrocatalytic properties vary with water content and are maximized near the composition RuO2·0.5 mol % H2O. We studied the atomic structure of RuO2·xH2O as a function of water content from x = 0.84 to 0.02 using X-ray diffraction and atomic pair density function (PDF). Even though the diffraction patterns of samples containing 0.84 to 0.35 mole of water are suggestive of “amorphous” structures, the PDF analysis clearly shows that up to 0.7 nm, the short-range atomic structure of all of these RuO2·xH2O samples resembles that of the anhydrous rutile RuO2 structure. We conclude that RuO2·xH2O is a composite of anhydrous rutile-like RuO2 nanocrystals dispersed by boundaries of structural water associated with Ru−O. Metallic conduction is supported by the rutile-like nanocrystals, while proton conduction is facilitated by the str...

264 citations

Journal ArticleDOI
TL;DR: In this paper, a new approach to the facile preparation of anhydrous proton exchange membrane (PEM) enabled by artificial acid-base pairs is presented, where polydopamine-modified graphene oxide (DGO) sheets bearing NH2 and NHNH groups are fabricated and then incorporated into sulfonated poly(ether ether ketone) (SPEEK) matrix to prepare the nanocomposite membrane.
Abstract: A new approach to the facile preparation of anhydrous proton exchange membrane (PEM) enabled by artificial acid–base pairs is presented herein. Inspired by the bioadhesion of mussel, polydopamine-modified graphene oxide (DGO) sheets bearing –NH2 and –NH– groups are fabricated and then incorporated into sulfonated poly(ether ether ketone) (SPEEK) matrix to prepare the nanocomposite membrane. The DGO sheets are interconnected and homogeneously dispersed in SPEEK matrix, which provides unique rearrangement of the nanophase-separated structure and chain packing of nanocomposite membrane through interfacial electrostatic attractions. These attractions meanwhile induce the generation of acid–base pairs along the SPEEK–DGO interface, which then serve as long-range and low-energy-barrier pathways for proton hopping, imparting an enhanced proton transfer via the Grotthuss mechanism. In particular, under both hydrated and anhydrous conditions, the nanocomposite membrane exhibits much higher proton conductivity than the polymer control membrane. The enhanced proton conductivity results in the nanocomposite membrane having elevated cell performances under 120 °C and hydrous conditions, yielding a 47% increase in maximum current density and a 38% increase in maximum power density. Together with the stable conduction property, these results guarantee the nanocomposite membrane's promising prospects in high-performance fuel cell under anhydrous and elevated temperature conditions.

259 citations

Journal ArticleDOI
TL;DR: Au(25) clusters supported on hydroxyapatite oxidized styrene in toluene with 100% conversion and 92% selectivity to the epoxide, under optimum conditions and using anhydrous tert-butyl hydroperoxide (TBHP) as an oxidant.

255 citations

Journal ArticleDOI
TL;DR: Anhydrous mesoporous ruthenium oxide was synthesized by a simple non-ionic surfactant templating method using Pluronic 123 and tested as an active electrode material for an electrochemical supercapacitor as mentioned in this paper.

237 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
2023190
2022411
2021147
2020314
2019533
2018734