Wikipedia

Kunstig fotosyntese

Kunstig fotosyntese er et forskningsområde som bl.a. forsøger at replikere den naturlige fotosynteseproces; det at konvertere solenergi, vand og carbondioxid – til oxygen og f.eks. kulhydrater.

Hvis kunstig fotosyntese har en virkningsgrad på 8%, kunne jordens energibehov dækkes af overfladearealet svarende til de sorte cirkelskiver på jordoverfladen.[1] Kunstig fotosyntese ville sagtens kunne anvendes i Danmark, men der skal så anvendes ca. dobbelt areal, i forhold til tættere ved ækvator og vi skal gemme energien f.eks. i form af syntetisk brændstof fra sommerhalvåret til vinterhalvåret.

Fotokatalytisk vandspaltning til hydrogen og oxygen under brug af solenergi, indregnes også som en del af kunstig fotosyntese, da fotosyntesens fotosystem II netop fraspalter hydrogenioner (protoner).

Faktisk kan alle processer som lagrer solenergi i kemiske bindinger eller kemiske forbindelser indbefattes under kunstig fotosyntese.

Da kunstig fotosyntese får sin energi fra solen kan den givne proces udføre CO2-neutral energilagring.

Vindmøller og solceller tilsammen med CO2-indvindende CO2-neutral energilagring med O2 som affaldsstof, har samme virkning som kunstig fotosyntese, da både solceller og vindmøller får deres energi direkte eller indirekte fra solenergi.

Mange forskere forsker i kunstig fotosyntese:

  • 2016
    • Forskere ved University of Illinois at Chicago har lavet en solcelle med wolframdiselenid-nanoflager, som kan omdanne CO2 og H2O til CO og H2 (syntesegas) - pt med en virkningsgrad på 6%.[2]
  • 2014
    • Amin Salehi-Khojin et al. ved University of Illinois at Chicago har udviklet en totrins katalytisk proces, der anvender MoS2 og en ionisk væske, som kan katalysere CO2 (og H2O?) til syngas (CO og H2). Forholdet mellem dannet CO og H2 kan let reguleres.[3]
  • 2013
    • Prof. Dr. Roel van de Krol et al. har lavet en prisgunstig, stabil og effektiv solcelle baseret på et rimelig lettilgængeligt metaloxid (BiVO4, bismut-vanadium-tetraoxid), som afleverer energien i brint (og ilt).[4]
  • 2012
    • Videnskabsfolk ved École Polytechnique Fédérale de Lausanne har lavet en ny fotokatalytisk vandspaltning baseret på billig rust.[5]
    • Forskere ved University of Rochester har syntetiseret en stabile CdSe-kvanteøer og en nikkel katalysator, som muliggør en effektiv fotokatalytisk vandspaltning.[6]
  • 2010
    • Mitsubishi udvikler sin egen kunstige fotosyntese som anvender sollys, vand og CO2 til "create the carbon building blocks from which resins, plastics and fibers can be synthesized".[7]
    • UCSC fremviser en synergieffekt mellem TiO2 og CdSe kvanteøer til soldreven hydrogen fremstilling.[8][9]
    • Et prototype solapparat som kan transformere H2O og CO2 til CO og H2. Virkningsgraden for prototypen er 0,7-0,8%, men prototypens varmeisolation er ikke optimal.[10]
  • 2009
  • 2008
  • 2007
    • CR5-solpaneler[19][20][21]
    • Et forskerhold under ledelse af dr. Hideki Koyanaka ved universitetet i Kyoto afslørede en proces, baseret på mangandioxid, som kunne opfange CO2 300 gange mere effektivt end planterne[22] (resultatet skal bekræftes ved offentliggørelse i et videnskabeligt tidsskrift).
    • Ved at anvende en halvleder og to tynde lag katalysatorer har Aaron Sathrum og Clifford Kubiak kunnet splitte carbondioxid til oxygen og carbonmonoxid.[23]
  • 2006 SLAC om fotogenerationsceller[24]
  • 2003 Brookhaven National Laboratory pressemeddelelse[25][26]
  • 2000 CSIRO pressemeddelelse om kunstig fotosyntese[27][28]
  • 1967 Akira Fujishima opdager Honda-Fujishima-effekten, hvilket kan anvendes til hydrolyse.

Kilder/referencer redigér

  1. ^ American Chemical Society (2008, April 11). Expert Foresees 10 More Years Of Research & Development To Make Solar Energy Competitive. ScienceDaily. Retrieved April 24, 2008 Citat: "..."Solar can potentially provide all the electricity and fuel we need to power the planet," Harry Gray, Ph.D...In his talk at the ACS Presidential Symposium, Gray cited the vast potential of solar energy, noting that more energy from sunlight strikes the Earth in one hour than all of the energy consumed on the planet in one year..."
  2. ^ 6. aug 2016, ing.dk: Ny type solcelle konverterer CO2 til brændstof Citat: "...Når denne celle rammes af lys med en intensitet af 100 watt pr. kvadratmeter - svarende til den gennemsnitlige intensitet af solens lys ved Jordens overflade - dannes hydrogen og carbonmonoxid ved katoden, mens fri oxygen og hydrogenioner dannes ved anoden...", July 28, 2016, uic.edu: Breakthrough solar cell captures CO2 and sunlight, produces burnable fuel Citat: "...The ability to turn CO2 into fuel at a cost comparable to a gallon of gasoline would render fossil fuels obsolete...The best of several catalysts they studied turned out to be nanoflake tungsten diselenide...In fact, he said, the new catalyst is 1,000 times faster than noble-metal catalysts — and about 20 times cheaper..."
  3. ^ University of Illinois at Chicago. (2014, July 30). New catalyst converts carbon dioxide to fuel. ScienceDaily Citat: "...Amin Salehi-Khojin, UIC professor of mechanical and industrial engineering, and his coworkers developed a unique two-step catalytic process that uses molybdenum disulfide and an ionic liquid to "reduce," or transfer electrons, to carbon dioxide in a chemical reaction. The new catalyst improves efficiency and lowers cost by replacing expensive metals like gold or silver in the reduction reaction..."With this catalyst, we can directly reduce carbon dioxide to syngas without the need for a secondary, expensive gasification process," he said. In other chemical-reduction systems, the only reaction product is carbon monoxide. The new catalyst produces syngas, a mixture of carbon monoxide plus hydrogen...The proportion of carbon monoxide to hydrogen in the syngas produced in the reaction can also be easily manipulated using the new catalyst, said Salehi-Khojin..."
  4. ^ Helmholtz Association of German Research Centres (2013, July 29). Best of both worlds: Solar hydrogen production breakthrough. ScienceDaily Citat: "..."Basically, we combined the best of both worlds," explains Prof. Dr. Roel van de Krol, head of the HZB Institute for Solar Fuels: "We start with a chemically stable, low cost metal oxide, add a really good but simple silicon-based thin film solar cell, and -- voilà -- we've just created a cost-effective, highly stable, and highly efficient solar fuel device."...We found that more than 80 percent of the incident photons contribute to the current, an unexpectedly high value that sets a new record for metal oxides"..."
  5. ^ Ecole Polytechnique Fédérale de Lausanne (2012, November 11). Using rust and water to store solar energy as hydrogen. ScienceDaily Citat: "...The efficiency is still low -- between 1.4% and 3.6%, depending on the prototype used. But the technology has great potential. "With our less expensive concept based on iron oxide, we hope to be able to attain efficiencies of 10% in a few years, for less than $80 per square meter. At that price, we'll be competitive with traditional methods of hydrogen production."..."
  6. ^ University of Rochester (2012, November 8). Nanocrystals and nickel catalyst substantially improve light-based hydrogen production. ScienceDaily Citat: "...These nanocrystals performed without any sign of deterioration for at least two weeks..."
  7. ^ "Man-made photosynthesis looking to change the world". Arkiveret fra originalen 10. juli 2010. Hentet 2. maj 2010.
  8. ^ Synergistic effect of CdSe quantum dot sensitization and nitrogen doping of TiO2 nanostructures
  9. ^ "Composite nanomaterials show promise for solar hydrogen generation". Arkiveret fra originalen 7. maj 2010. Hentet 2. maj 2010.
  10. ^ 24 December 2010, sciencemag.org: High-Flux Solar-Driven Thermochemical Dissociation of CO2 and H2O Using Nonstoichiometric Ceria Citat: "...By using a solar cavity-receiver reactor, we combined the oxygen uptake and release capacity of cerium oxide and facile catalysis at elevated temperatures to thermochemically dissociate CO2 and H2O, yielding CO and H2, respectively. Stable and rapid generation of fuel was demonstrated over 500 cycles. Solar-to-fuel efficiencies of 0.7 to 0.8% were achieved and shown to be largely limited by the system scale and design rather than by chemistry...", 23 December 2010, BBC News: New solar fuel machine 'mimics plant life'
  11. ^ 14. apr 2009, Ing.dk: Israelsk opdagelse spalter vand med sollys og varme (Webside ikke længere tilgængelig)
  12. ^ Weizmann Institute of Science (2009, April 8). New Way To Split Water Into Hydrogen And Oxygen Developed. ScienceDaily. Retrieved April 14, 2009 Citat: "...The new approach that the Weizmann team has recently devised is divided into a sequence of reactions, which leads to the liberation of hydrogen and oxygen in consecutive thermal- and light-driven steps, mediated by a unique ingredient – a special metal complex..."
  13. ^ Light-Driven Hydrogen Generation System Based on Inexpensive Iron Carbonyl Complexes
  14. ^ Light-Driven Hydrogen Generation System Based on Inexpensive Iron Carbonyl Complexes (Webside ikke længere tilgængelig)
  15. ^ Water Splitting by Visible Light: A Nanophotocathode for Hydrogen Production (Webside ikke længere tilgængelig)
  16. ^ Helmholtz Association of German Research Centres (2008, March 26). Artificial Photosynthesis Moves A Step Closer. ScienceDaily. Retrieved April 14, 2009 Citat: "..."Our water-soluble tetraruthenium complex displays its effects in aqueous solution already at ambient temperature," enthuses Prof. Paul Kögerler from the Jülich Institute of Solid State Research..."
  17. ^ Electrode lights the way to artificial photosynthesis
  18. ^ Solar-Power Breakthrough: Researchers have found a cheap and easy way to store the energy made by solar power
  19. ^ 11. dec 2007, Ing.dk: Dansk professor: Vi skal spalte andet end vand Arkiveret 13. december 2007 hos Wayback Machine Citat: "...Ved hjælp af en solfanger vil de oparbejde forbrændingsprodukterne vand og CO2 til brændstofferne CO (kulilte) og ilt. Kulilten kan videreforarbejdes til syntetiske, flydende brændsler som metanol, benzin, diesel eller jetbrændstof..."
  20. ^ "December 7, 2007, sandia.gov: Sandia's Sunshine to Petrol project seeks fuels from thin air" (PDF). Arkiveret fra originalen (PDF) 11. maj 2009. Hentet 14. april 2009.
  21. ^ 11. dec 2007, Ing.dk: Omvendt forbrænding i ny solfanger Arkiveret 16. maj 2008 hos Wayback Machine Citat: "...Den samme solfanger kunne bruges til at oparbejde forbrændingsprodukterne vand og CO2 til brændstofferne CO (kulilte) og ilt. Dermed bliver det muligt at videreforarbejde kulilten til syntetiske flydende brændsler [ og dermed gemme vedvarende energi; sollys ] som metanol, benzin, diesel eller jetbrændstof..."
  22. ^ IT-meddelelse nr. 435 fra Japan Arkiveret 6. september 2008 hos Wayback Machine, via Barbara Ngouyombo ved den franske ambassade i Japan
  23. ^ University of California – San Diego (2007, April 18). Device Uses Solar Energy To Convert Carbon Dioxide Into Fuel. ScienceDaily. Retrieved April 14, 2009 Citat: "...Now Clifford Kubiak, professor of chemistry and biochemistry, and his graduate student Aaron Sathrum have developed a prototype device that can capture energy from the sun, convert it to electrical energy and “split” carbon dioxide into carbon monoxide (CO) and oxygen...“The technology to convert carbon monoxide into liquid fuel has been around a long time,” said Kubiak. “It was invented in Germany in the 1920s..."
  24. ^ 2006 – photogeneration cells – Slac
  25. ^ Designing a Better Catalyst for Artificial Photosynthesis
  26. ^ Designing A Better Catalyst For 'Artificial Photosynthesis'
  27. ^ Scientists Developing "Artificial" Plants
  28. ^ Artificial Photosynthesis

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