Polycondensation

Yokozawa, Tsutomu

doi:10.1002/9783527631421.ch8

Cited by 5 publications

(2 citation statements)

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“…In this way, production of hydrogen and oxygen was achieved photoelectrochemically by means of sunlight irradiation in which a ruthenium(II) dye was the light absorber. 237 Along similar lines, Sato and Ishizuka 193 set out to provide a photocatalyst with significant activity also upon irradiation with sunlight when suspended in water. They prepared laminar composite metal compounds AMWO 6 (A = alkali metal and/or H, and M = V, Nb or Ta) and added a semiconductor that could be excited by light and that was included between the layers of the laminar composite metal compound and loaded (0.05-5 wt%) with a metal selected from Pt, Ru, Rh, Ir and Ni, or their oxides as co-catalysts.…”

Section: Photocatalysts For Hydrogen Generation From Water: Group 6 O...mentioning

confidence: 96%

Photocatalytic generation of solar fuels from the reduction of H₂O and CO₂: a look at the patent literature

Protti

Albini

Serpone

2014

Phys. Chem. Chem. Phys.

106

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The application of photocatalysis in environment remediation as well as in the generation of useful fuels from the reduction of water (hydrogen) and of carbon dioxide (methanol, carbon monoxide and/or methane) has been investigated largely in the last four decades. A significant part (12-13%) of the literature on the generation of such fuels is found in patents. Accordingly, the present article presents a selection of the patent literature on the theme. Photocatalysts, whether pure or doped, solid solutions or composites, reported in patents are reviewed along with the corresponding preparative methods and the photocatalytic performance. The absorption of light by such materials has been extended toward the red side of the spectrum, so that a better use of solar irradiation has been obtained, but the expected improvement of the catalytic effect has not always been achieved. The causes of these results and the way for improving the performance in the various steps of the process (e.g. avoiding charge recombination or catalyst corrosion) have been documented. The correct use of the term water splitting and the fundamentals of photochemical hydrogen evolution in the presence of a sacrificial electron donor (e.g., alcohols) are discussed. Quantitative data about the amount of hydrogen evolved or carbon-based fuels produced are indicated whenever available.

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Section: Photocatalysts For Hydrogen Generation From Water: Group 6 O...mentioning

confidence: 96%

Photocatalytic generation of solar fuels from the reduction of H₂O and CO₂: a look at the patent literature

Protti

Albini

Serpone

2014

Phys. Chem. Chem. Phys.

106

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“…Stepgrowth polycondensation [44][45][46][47] not only differs from other polymerization techniques from the point of view of its kinetics and plots of molecular weight versus conversion, but also requires different experimental techniques. When considering the state-of-the-art here, it is apparent that this field of polymer chemistry has especially profited from the development of new monomeric building blocks, new methods of catalysis, particularly those using transition-metal complexes, and from deeper mechanistic insights [48,49].…”

Section: Expanding Synthetic Chemistry To Complex Macromoleculesmentioning

confidence: 99%

Graphene as a Target for Polymer Synthesis

Müllen

2013

Advances in Polymer Science

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Graphene has remarkable physical properties, but existing production methods have severe deficiencies that limit its potential use in robust technologies. Opening a reliable and efficient synthetic route to graphene and its functionalized derivatives offers a path to overcome this obstacle for its practical application. Graphene can be regarded as a two-dimensional polymer (2D), and it is here argued that it, along with its derivatives, represents a realistic yet challenging target for polymer synthesis.In order to demonstrate the possibility of such syntheses, an overview is presented on the evolution of phenylene-based macromolecules. It is shown how classical linear polyphenylenes can be expanded to increasingly more sophisticated structures involving two-and three-dimensional (3D) polyphenylene architectures. A crucial aspect of the meticulous synthetic design of these molecules has been the avoidance of defects within the structures, resulting in the precise control of their physical, especially optoelectronic, properties.Linear conjugated polymers with defined optical properties have been made by controlling the degree of torsion between the benzene rings. This has included the development of efficient routes to ladder-type polymers and of step-ladder materials. Planar graphene molecules, or nanographenes, in a range of sizes and shapes have been fabricated by the controlled cyclodehydrogenation of 3D polyphenylene dendrimers. By combining knowledge gained from the synthesis of conjugated polymers, polyphenylene dendrimers, and nanographenes, it has proven feasible to make, either by solution or surface-bound methods, graphene nanoribbons with well-defined structures. These functional materials possess properties similar to graphene while displaying improved processability.Finally, we review less-sophisticated paths towards graphene materials involving processing of graphene oxide, its reduction, and its hybridization with other components. These too have a role to play in acquiring functional graphenes where K. Müllen (*) Max-Planck-Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany e-mail: muellen@mpip-mainz.mpg.de a lesser degree of control over the properties is required. This voyage of exploration towards the precise synthesis of conjugated phenylene-based polymers has thus had the dual objectives of fundamental research and practical materials science. En route we have had to meet the sometimes conflicting gauntlets thrown down by these two aims, which has at times involved trade-offs between the theoretically desirable and the reasonably accessible.

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Energetic Nitrogen‐Rich Polymers with a Tetrazene‐Based Backbone

et al. 2020

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New energetic polymers were synthesized from monomers containing a trans-2-tetrazene unit. In contrast to traditional binders, such as inert hydroxytelechelic polybutadiene or glycidyl azide polymers-in which the energetic features are on the side chains-the energetic groups in the polytetrazenes are incorporated directly in the polymer backbone. Thermal analyses demonstrated that decomposition occurs at approximately 130 8C, regardless of the polymer structure. Glass-transition temperatures ranged from À34.2 to 0.2 8C and could be lowered further (to À61 8C) with the help of a new diazidotetrazene energetic plasticizer. Interestingly, hexafluoroisopropanol (HFIP) enabled complete, room-temperature depolymerization within 1 week. This depolymerization should enable the recycling of unused pyrotechnic compositions based on these new binders.

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Polycondensation

Cited by 5 publications

References 157 publications

Photocatalytic generation of solar fuels from the reduction of H₂O and CO₂: a look at the patent literature

Photocatalytic generation of solar fuels from the reduction of H₂O and CO₂: a look at the patent literature

Graphene as a Target for Polymer Synthesis

Energetic Nitrogen‐Rich Polymers with a Tetrazene‐Based Backbone

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Polycondensation

Cited by 5 publications

References 157 publications

Photocatalytic generation of solar fuels from the reduction of H2O and CO2: a look at the patent literature

Photocatalytic generation of solar fuels from the reduction of H2O and CO2: a look at the patent literature

Graphene as a Target for Polymer Synthesis

Energetic Nitrogen‐Rich Polymers with a Tetrazene‐Based Backbone

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Product

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Photocatalytic generation of solar fuels from the reduction of H₂O and CO₂: a look at the patent literature

Photocatalytic generation of solar fuels from the reduction of H₂O and CO₂: a look at the patent literature