Après le précédent sur l'équipe de l'université du Wisconsin qui a découvert des bactéries fabriquant de l'Hydrogène à grandes quantités... Une équipe de l'école Polytechnique Fédérale de Lausanne (EPFL) vient de proposer l'utilisation des panneaux solaires (donc de l'énergie solaire) pour la fabrication de l'Hydrogène (Hydrogen Fuel) à bas cout !!!

Ecole Polytechnique Fédérale de Lausanne. "New method can make cheaper solar energy storage. " ScienceDaily. ScienceDaily, 1 July 2015. <www. sciencedaily. com/releases/2015/07/150701083720. htm>

Storing solar energy as hydrogen is a promising way for developing comprehensive renewable energy systems. To accomplish this, traditional solar panels can be used to generate an electrical current that splits water molecules into oxygen and hydrogen, the latter being considered a form of solar fuel. However, the cost of producing efficient solar panels makes water-splitting technologies too expensive to commercialize. EPFL scientists have now developed a simple, unconventional method to fabricate high-quality, efficient solar panels for direct solar hydrogen production with low cost. The work is published in Nature Communications.

Many different materials have been considered for use in direct solar-to-hydrogen conversion technologies but "2-D materials" have recently been identified as promising candidates. In general these materials--which famously include graphene--have extraordinary electronic properties. However, harvesting usable amounts of solar energy requires large areas of solar panels, and it is notoriously difficult and expensive to fabricate thin films of 2-D materials at such a scale and maintain good performance.

Kevin Sivula and colleagues at EPFL addressed this problem with an innovative and cheap method that uses the boundary between two non-mixing liquids. The researchers focused on one of the best 2-D materials for solar water splitting, called "tungsten diselenide. " Past studies have shown that this material has a great efficiency for converting solar energy directly into hydrogen fuel while also being highly stable.

Before making a thin film of it, the scientists first had to achieve an even dispersion of the material. To do this, they mixed the tungsten diselenide powder with a liquid solvent using sonic vibrations to "exfoliate" it into thin, 2-D flakes, and then added special chemicals to stabilize the mix. Developed by Sivula's lab (2014), this technique produces an even dispersion of the flakes that is similar to an ink or a paint.

The researchers then used an out-of-the-box innovation to produce high-quality thin films: they injected the tungsten diselenide ink at the boundary between two liquids that do not mix. Exploiting this oil-and-water effect, they used the interface of the two liquids as a "rolling pin" that forced the 2-D flakes to form an even and high-quality thin film with minimal clumping and restacking. The liquids were then carefully removed and the thin film was transferred to a flexible plastic support, which is much less expensive than a traditional solar panel.

The thin film produced like this was tested and found to be superior in efficiency to films made with the same material but using other comparable methods. At this proof-of-concept stage, the solar-to-hydrogen conversion efficiency was around 1%--already a vast improvement over thin films prepared by other methods, and with considerable potential for higher efficiencies in the future.

More importantly, this liquid-liquid method can be scaled up on a commercial level. "It is suitable for rapid and large-area roll-to-roll processing, " says Kevin Sivula. "Considering the stability of these materials and the comparative ease of our deposition method, this represents an important advance towards economical solar-to-fuel energy conversion. "

This work was funded by the Swiss Competence Centers for Energy Research (SCCER Heat and Electricity Storage) and the European Commission's Framework Project 7 (FP7) through a Marie-Curie Intra-European Fellowship (COCHALPEC).

Story Source:

The above post is reprinted from materials provided by Ecole Polytechnique Fédérale de Lausanne. Note: Materials may be edited for content and length.

Journal Reference:

Xiaoyun Yu, Mathieu S. Prévot, Néstor Guijarro, Kevin Sivula. Self-assembled 2D WSe2 thin films for photoelectrochemical hydrogen production. Nature Communications, 2015; 6: 7596 DOI: 10. 1038/ncomms8596

Non, Monsieur, l'Algérie ne négocie pas avec l'Europe, elle magouille avec l'Europe, car pour négocier il faut être deux, or, dans les pourparler de ces genres, les Algériens cherchent plus combien il vont percevoir de ristourne sur les contrats, et comment s'en sortir de l'histoire du gaz de schiste au Sahara.

On négocie lorsque on agit dans l'intérêt de son pays et pour le bien de son pays et de son peuple,

malheureusement l'histoire des négociations des contrats en Algérie, c'est de la corruption depuis l'arrivée au pouvoir du président actuel, ils font les chroniques de la presse internationale, quand au bien du peuple, il est inutile d'en parler, car il n'existe pas, puisqu'il n'a pas le droit de cité et moins encore de parler, les mafieux et la charia de ceux qui gouverne dans ce pays décident à la place du peuple, et les généraux surveillent leurs intérêts et avec des mafieux.