1 / 21

Artificial Photosynthesis

Its a ppt upon concept of artificial photosynthesis where we can understand about the green way of producing energy by utilizing natural photosynthesis path.

Rajesh13
Télécharger la présentation

Artificial Photosynthesis

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. ARTIFICIAL PHOTOSYNTHESIS GUIDED BY: - Dr. Vinod Kumar Associate professor Department of chemistry School of basic science Central University of Punjab Submitted by: - Rajesh Sahoo MSc Chemistry (Specialized applied chemistry) 20Mschac10

  2. CONTENTS • INTRODUCTION • REVIEW ABOUT BIOLOGICAL PHOTOSYNTHESIS • THE PREREQUISITE OF ARTIFICIAL PHOTOSYNTHESIS • ARTIFICIAL PHOTOSYNTHESIS • LITRETURE SURVEY • MECHANISM OF ARTIFICIAL PHOTOSYNTHEIS • PHOTOELECTROCHEMICAL CELL • ADVANTAGES OF ARTIFICIAL PHOTOSYNTHESIS • FUTURE ASPECTS OF ARTIFICIAL PHOTOSYNTHESIS • CONCLUSION • REFERENCE

  3. INTRODUCTION: - • From million of years plants acting like arbitrator to capture solar energy and converting it into energy of chemical bonds of organic molecules that are the building blocks of all living organisms and also of oil, gas and coal. • These fossil fuels are the products of photosynthetic activity, which provide the energy needed to power our technologies, heat our homes and produce the wide range of chemicals and materials that support everyday life. • According to a survey 82% of the global TPES (Total primary energy supply) came from fossil fuels in 2014 to maintain the global population. • Its rate increased to 84% in 2019, so fossil fuels are not estimated to keep sustaining the ever-increasing global energy demand. Shades of grey is the fossil fuel region-84%

  4. What is Photosynthesis ? • Photosynthesis is an energy generating and storage system. In nature plants use the process called photosynthesis to convert solar energy, carbon dioxide and water to oxygen and carbohydrate food source for life on earth. • Chlorophyll is to be used as a vital piece to power of this process. It capture the energy of sunlight and allow it to be used to power the complex chemical reactions. • https://ncert.nic.in/textbook/pdf/kebo113 • https://www.weforum.org/agenda/2016/08/should-all-roads-and-buildings-make-clean-fuel-food-and-fertilizer-from-sunlight-water-and-air/

  5. The prerequisite of Artificial photosynthesis- • Photosynthesis depends upon so many external and internal factors like number, size, age and orientation of leaves, mesophyll cells( a type of tissue which allow CO2 to move freely) and chloroplasts of leaves, these are the internal factors. And The external factors would include the availability of sunlight, temperature, CO2 concentration and water. • The efficiency of plant photosynthesis i.e. fraction of light energy converted into chemical energy during photosynthesis is less that 10%. Sugar cane the most efficient plant absorb only 8% of light for chemical energy. • Even though light is utilized in photosynthesis but too much light also damage and degrade the system of photosynthesis. • The ever growing industrialization, society and reduction of plants, forests also need this alternate approach • Barber J, Tran PD. 2013 From natural to artificial photosynthesis. J R Soc Interface 10: 20120984. https://doi.org/10.1098/rsif.2012.0984. • https://ncert.nic.in/textbook/pdf/kebo113

  6. Artificial photosynthesis- • Artificial photosynthesis is a chemical process that replicates the natural process of photosynthesis, a process that converts sunlight, water and carbon dioxide into carbohydrates and oxygen. • The topic include the direct production of solar fuels, reduce CO2 to methane, methanol, formaldehyde, formate, carbon monoxide or oxalate, and also reduce proton to hydrogen molecule. a) Natural, and (b) artificial photosynthesis through water splitting and CO2 reduction, and (c)photodegradation of aqueous organic pollutants.  https://www.researchgate.net/figure/a-Natural-and-b-artificial-photosynthesis-through-water-splitting-and-CO2-reduction_fig1_323087450

  7. History: - • Artificial photosynthesis was first anticipated by the Italian chemist Giacomo Comedian during 1912 in a lecture. he proposed a switch from the use of fossil fuels to radiant energy provided by the sun and captured by technical photochemistry devices. • Visible light water splitting with a one-piece multijunction semiconductor device (vs. UV light with titanium dioxide semiconductors) was first demonstrated and patented by William Ayers at Energy Conversion Devices during 1983. He also demonstrated about low cost artificial leaf using thin film amorphous silicon multijunction sheet. • In 2008, Andrew B. Bocarsly reported the direct conversion of carbon dioxide and water to methanol using solar energy in a very efficient photochemical cell. • During 2011, Daniel Nocera and his research team announced the creation of the first practical artificial leaf with a size of poker card capable of splitting water into oxygen and hydrogen with 10 times more efficient than natural photosynthesis. • Bolton JR, Hall DO. 1991 The maximum efficiency of photosynthesis. Photochem. Photobiol. 53, 545– 548 • . https://doi.org/10.1111/j.1751-1097.1991.tb03668.x • Wikipedia( http://www.Wikipedia.org)

  8. A sample of a photoelectric cell in a lab environment. Catalysis are added to the cell which is submerged in water and illuminated by simulated sunlight. The bubbles seen are oxygen( forming on the front of the cell) and hydrogen( forming on the back of the cell).

  9. MECHANISM OF ARTIFICIAL PHOTOSYNTHESIS: - • In order to develop a photoelectrochemical cell we need to focus upon different design and synthesize techniques according to human needs. • Instead of releasing only oxygen at the end of the reaction, it would have to release liquid hydrogen, and the hydrogen used directly as liquid fuel of fuel cells. And also the hydrogen is used to reduce carbon dioxide to carbohydrate and any other forms. So we need different processes as well to conduct all these work – • Light harvesting system • Water oxidation • Proton reduction • CO2 reduction

  10. Water oxidation Proton reduction Light harvest CO2 Reduction Photoelectrochemical cell

  11. LIGHT HARVESTING SYSTEM: - Materials that absorb light with a suitable wavelength of light that has sufficient energy to promote an electron from a low energy molecular orbital (ground state) to a higher energy orbital (excited state). Materials absorbs light in the visible region of the electromagnetic spectrum i.e. 400–700 nm. The conversion of solar energy directly to electrical energy is termed photovoltaics whilst the conversion of solar energy to chemical energy is called photosynthesis. The semiconductors for solar cells but those have low efficiency. According to recent developments we have thin film solar cells, multiple junction solar cells, organic/polymer solar cells, Quantum Dot Solar Cells (QDSCs), and Dye Sensitised Solar Cells (DSSCs) . • Barber J, Tran PD. 2013 From natural to artificial photosynthesis. J R Soc Interface 10: 20120984. https://doi.org/10.1098/rsif.2012.0984

  12. Semiconductor type photovoltaic cell Dye sensitized solar cell Multi junction solar cell Quantum dot solar cell Thin film solar cell

  13. WATER OXIDATION: - • Water oxidation is one the successful development for water splitting cell with sunlight. It involves the removal of 4H+ and 4e- together with the generation of an O–O bond. • Splitting of water requires an energy input of about 2.5 volts. Manganese: a single atom manganese triggers the natural process that uses sunlight to split water, the using of manganese is a biomimetic approach in artificial photosynthesis. Cobalt oxide: recently developed clusters of Nano-sized cobalt oxide(CoO) have been found to be stable and highly efficient triggers in an artificial photosynthesis. The other molecular rationally design WOCs performance based on ligand modifications, choice of transition metal, oxidation state and geometry, through space interactions, electronic coupling, and active site hindering are also seen in recent developments. • Berardi. S, Drouet. S, Franca. L, 2014 Molecular artificial photosynthesis. Chem Soc Rev. https://doi.org/10.1039/C3CS60405E • J. H., Brennaman, M. K. & Meyer, T. J. 2005 Chemical approaches to artificial photosynthesis 2. Inorg. Chem. 44, 6802–6827. https://doi.org/10.1021/ic050904r

  14. PROTON REDUCTION- • The reduction of protons into molecular hydrogen is a two electron process, and from a thermodynamic point of view. some time this process is thermodynamic suitable but kinetically slow due to absence of suitable catalysts. • rhodium and platinum, cobalt, nickel, molybdenum are used because of their high reactivity towards protons as colloids and their ability to easily form metal hydrides in both aqueous and organic medium.

  15. CO2 REDUCTION:- • Artificial photosynthesis system store solar energy in chemical fuels via CO2 reduction. • In nature carbon fixation is done by green plants using the enzyme RuBisCO as a part of Calvin cycle and results in the production of glucose which is a precursor to form cellulose and starch. • The injection of one electron into CO2 requires a lot of energy, the potential of the CO2/CO2- redox couple is highly negative (-1.9 V vs. NHE), due to rearrangement from a linear to a bent structure.

  16. CO2 Reduction mechanism- • The first step towards CO2 reduction is coordination to a reduced metallic centre (Mn+) to give Mn+L(CO2). • The CO2 molecule possesses both acidic and basic properties and the carbon atom is susceptible to be attacked by nucleophiles and the oxygen atoms are susceptible to be attacked by electrophiles. • The addition of CO2 and addition of H+ on the active reduced form of the catalyst leading to bond cleavage and release of CO or to a metal hydride intermediate H–Mn+ L. • This metal hydride can undergo two competing processes, it can either react with CO2 to give formate (HCO2-) or it can react with H+ to produce molecular hydrogen (H2). • Bruce A, Faunce T. 2015 Sustainable fuel, food, fertilizer and ecosystems through a global artificial photosynthetic system: overcoming anticompetitive barriers. Interface Focus 5: 20150011. http://dx.doi.org/10.1098/rsfs.2015.0011

  17. Photoelectrochemical cells (PECs) • The conversion of solar energy into chemical fuels can be achieved via water splitting, by means of sunlight-storing devices i.e. with assembly of suitable modules for light harvesting, water oxidation and proton reduction in a single PEC, mimicking natural photosynthesis. • The overall water splitting process can be divided into the two half reactions, so that water oxidation and proton reduction are carried out in two separate compartments. Each compartment contains an electrode (respectively the anode, performing water oxidation, and the cathode, performing proton reduction), connected through an external circuit for electron flow. • Finally, a proton exchange membrane (PEM) can be used to physically separate the two compartments, thus simplifying the product (O2 and H2) collection and avoiding their potentially hazardous reaction back to H2O.

  18. ADVANTAGES OF ARTIFICIAL PHOTOSYNTHESIS- • a new and ideal and pollution free process. • artificial photosynthesis has the potential to produce more than one type of fuels. • clean fuel without generating any harmful by-products, like greenhouse gasses • store and transport to working place.

  19. Future Aspects of Artificial Photosynthesis: - • Researchers of Cambridge working on to build wairless device to convert sunlight, carbon dioxide, and water into carbon-neutral fuel without requiring an external supply of electricity. • Semiconducting polymer bulk heterojunction photoanode for solar water oxidation. • Conversion of greenhouse gas into plastic, fuel, and other economic products. • Production of low-cost electricity with highly efficient solar cells. • Non corrode long term used product formation

  20. CONCLUSION- • During the last decade the field has advanced enormously at all fronts and even though catalysts and photosensitisers should be further improved in terms of overall performance in aqueous solutions and even on dark also. • Already we are faced with the prospect of catastrophic climate change owing to the release of CO2 into the atmosphere brought about by the burning of fossil fuels. In the short-term, we must exploit all technologies known to us to produce energy while at the same time reduce CO2 emission. • The production of photochemical cell should be cheap in price with thermodynamic and kinetically stable and should available for lifestyle of our developed societies, and also to attain decent living standards in developing and poor countries.

  21. Reference- Barber J, Tran PD. 2013 From natural to artificial photosynthesis. J R Soc Interface 10: 20120984. https://doi.org/10.1098/rsif.2012.0984 Bruce A, Faunce T. 2015 Sustainable fuel, food, fertilizer and ecosystems through a global artificial photosynthetic system: overcoming anticompetitive barriers. Interface Focus 5: 20150011. http://dx.doi.org/10.1098/rsfs.2015.0011 Berardi. S, Drouet. S, Franca. L, 2014 Molecular artificial photosynthesis. Chem Soc Rev. https://doi.org/10.1039/C3CS60405E J. H., Brennaman, M. K. & Meyer, T. J. 2005 Chemical approaches to artificial photosynthesis 2. Inorg. Chem. 44, 6802–6827. https://doi.org/10.1021/ic050904r Sovacool BK, Gross A. 2015 The social acceptance of artificial photosynthesis: towards a conceptual framework. Interface Focus 5: 20140089. http://dx.doi.org/10.1098/rsfs.2014.0089 Bolton JR, Hall DO. 1991 The maximum efficiency of photosynthesis. Photochem. Photobiol. 53, 545– 548. https://doi.org/10.1111/j.1751-1097.1991.tb03668.x Wikipedia( http://www.Wikipedia.org) https://ncert.nic.in/textbook/pdf/kebo113

More Related