Ashley Kloepper
Harrison Ingold
Julianna Kubiak
Chemistry of Light-Based Technologies: Photocatalysis
Introduction
A. General Purposes / Uses of Solar Energy
· Ref 1: Schultz, D. M.; Yoon, T. P. (2014, February 28 Solar Synthesis: Prospects in Visible Light Photocatalysis D. M. Schultz, T. P. Yoon, Science 343, 1239176 (2014).
o Sunlight is an abundant, renewable, and inexpensive energy source
· Ref 2: “Light.” Merriam-Webster. 2015. Web. 30 Jan. 2015 <http://www.merriam-webster.com/dictionary/light>
o Electromagnetic radiation consisting of infrared to X-rays and everything inbetween
· Ref 3: "Solar." EIA Energy Kids. Web. 31 Jan. 2015. <http://www.eia.gov/kids/energy.cfm?page=solar_home>.
o After solar energy is converted to thermal energy, it can be used to heat water and spaces in homes, pools, buildings, and greenhouses; it can be used to heat fluid which produces steam that powers a generator
o Benefits include no production of air pollutants or CO2 and little impact on the environment when placed on buildings
· Ref 4: Otanicar, T.; Golden, J. Environmental Science & Technology 2009, 43, 6082–6087.
o Solar powered hot water heaters reduce greenhouse gas and smog emissions caused from the combustion of fossil fuels
· Ref 5: SEIA http://www.seia.org/policy/solar-technology/concentrating-solar-power (accessed Jan 31, 2015).
o Concentrating Solar Power (CSP) collects energy from the sun using mirrors that reflect sunlight into receivers, which convert the sunlight into heat, generating electricity
· Ref 6: Solar Photovoltaic Cells. Mickey, C. Journal of Chemical Education 1981, 58. 418-423
o Solar cells use the photovoltaic effect to convert sunlight to electricity
· Ref 7: Wallington, T. J.; Anderson, J. E.; Mueller, S. A.; Morris, E. Kolinksi; Winkler, S. L.; Ginder, J. M.; Nielsen O. J. Corn Ethanol Production, Food Exports, and Indirect Land Use Change Am. Chem. Soc. 2012, 46, 6379-6384.
o Biomass is a renewable resource that can be chemically converted to fuel.
· Ref 8: “Photocatalysis.” Merriam-Webster. 2015. Web. 30 Jan. 2015 <http://www.merriam-webster.com/medical/photocatalysis>
o A chemical reaction accelerated by light that acts either directly or excites a substance to catalyze the main reaction
B. General Types of Photocatalysis
· Ref 9: Green Earth Nano Science. N.p., 2014. Web. 30 Jan. 2015. Inc.<http://www.greenearthnanoscience.com/what-is-photocatalyst.php>
o Catalysts increase the reaction’s rate by lowering the activation energy, without being changed or consumed
o Photochemistry is enabled/accelerated by photocatalysis
· Ref 10: Basic Functions of Photocatalyst. Web. 31 Jan 2015 <http://www.tipe.com.cn/library/kb2503.htm>
o Sterilizing effect: kills bacteria cells and can decompose the cell itself
o Deodorizing effect: hydroxyl radicals can destroy molecular bonds which quickens the breakdown of Volatile Organic Compounds (VOCs)
o Air purifying effect: can reduce or eliminate polluted compounds in air, protect lamp-houses and walls in tunneling, prevent white tents from becoming sooty and dark, and eventually remove CFCs, greenhouse gases, and more
o Anti fogging, self cleaning: creates self cleaning buildings that are “antistatic, super oxidative, and hydrophilic”
o Water purification: can disinfect certain bacteria and with UV light, can oxidize organic pollutants into materials that aren’t toxic such as CO2
· Ref 11: Ângelo, J.; Andrade, L; Luís, M. M.; Adélio M. Journal of Environmental Management. 2013, 129, 522-539.
o Titanium dioxide is an excellent semiconductor photocatalysis
o Coating buildings and roads with photocatalytic TiO2 reduces pollutants in the area
· Ref 12: Photocatalytic Hydrogen Production by Direct Sunlight: A Laboratory Experiment. Koca, A.; Sahin, M. J. Chem. Educ. 2003, 80, 1314-1315.
o Hydrogen can be produced through photocatalysis of water
o Hydrogen fuel causes less pollution than fossil fuels
o Hydrogen’s future uses include heating homes and offices, generating electricity, industrial processes, and transportation
· Ref 13: Xu, C.; Yang, W.; Guo, Q.; Dai, D.; Chen, M.; Yang, X. Journal of the American Chemical Society 2014, 136, 602–605.
o Photocatalyst studied is A-TiO2
· Ref 14: “Biomass.” Merriam-Webster. 2015. Web. 31 Jan. 2015
o Biomass (plant materials, animal wastes) is a fuel source
· Ref 7:
o Chemically conversion of biomass (i.e., corn) generates fuels like ethanol.
· Ref 15: Yadv, Rajesh K.; Baeg, Jin-Ook; Oh, Gyu Hwan; Park, No-Joong; Kong, Ki-jeong; Kim, Jinheung; Hwang, Dong Won; Biswas, Soumya K. A Photocatalyst-Enzyme Coupled Artificial Photosynthesis System for Solar Energy in Production of Formic Acid from CO2 J. Am. Chem. Soc. 2012, 134, 11455-11461.
o Artificial photosynthesis with a photocatalyst coupled-enzyme system
o Graphene-based photocatalyst coupled with a biocatalyst
o Formation of formic acid from CO2
Materials and Methods
Results
Discussion
Conclusion
References
Chemistry of Light-Based Technologies: Photocatalysis
Introduction
A. General Purposes / Uses of Photocatalysis
Sunlight is an abundant, renewable, and inexpensive energy source.[1] Light is defined as electromagnetic radiation consisting of infrared light to X-rays and everything in between.[2] Electromagnetic radiation is the basis of solar energy applications. Benefits include no production of air pollutants or CO2 and little impact on the environment when placed on buildings.[3] There are five major modes of solar energy applications: heat, concentrating solar power (CSP), solar cells, biomass, and photocatalysis. The first mode, heat, involves converting solar energy to thermal energy which can be used to heat water and spaces in homes, pools, buildings, and greenhouses; also, it can be used to heat fluid which produces steam that powers a generator.3 These solar powered hot water heaters reduce greenhouse gas and smog emissions caused from the combustion of fossil fuels.[4] The second mode, CSP, collects energy from the sun using mirrors that reflect sunlight into receivers, which convert the sunlight into heat, generating electricity.[5] The third mode, solar cells, uses the photovoltaic effect to convert sunlight to electricity.[6] The fourth mode is biomass to fuel conversion, which uses renewable resources such as plant materials by chemically converting them to fuel.[7] The fifth mode of solar energy is photocatalysis. Photocatalysis is a chemical reaction accelerated by light that acts either directly or excites a substance to catalyze the main reaction.[8]
B. General Types of Photocatalysis
The field of photocatalysis is concerned with photochemical reactions which are made possible and/or more efficient by the use of a photocatalyst.8 The catalyst absorbs light and generates electrons and holes. Because of this charge separation, the catalyst enables reductions and oxidations without being changed or consumed.[9] Photocatalysis has many common applications including sterilization, deodorization, air purification, anti fogging and self-cleaning, and water purification. For sterilization, it can kill bacteria cells and can decompose the cell itself.[10] For deodorizing, photocatalytically generated hydroxyl radicals can destroy Volatile Organic Compounds (VOCs).10 The most significant air purification effects include the reduction or elimination of polluted compounds in the air, and eventually the removal of greenhouse gases.10 When used for anti-fogging and self-cleaning, it creates self-cleaning buildings that are “antistatic, super oxidative, and hydrophilic”.10 Photocatalysis can also be used to purify water (i.e., kill certain bacteria).10 When coupled with UV light, it can oxidize organic pollutants into materials that are not toxic such as CO2.10 Photocatalysis can be applied in five major ways. First, photocatalysis can be used in the environment to reduce pollutants by coating buildings and roads with photocatalytic TiO2.[11] Photocatalysis is a major factor in the production of H2 from fuel conversion and water splitting.[12] In the future, hydrogen will replace or reduce the use of certain fossil fuels and thereby decrease pollution.12 It will also be used to heat homes and offices, generate electricity, and for transportation.12 An example of a photocatalyst used in fuel to hydrogen conversion is A-TiO2.[13] Fourth, in biomass to fuel conversion, biomass is chemically converted to liquid fuels such as ethanol.7 Biomass is defined as plant materials or the waste of animals.[14] Fifth, photocatalysis is key to the reduction of CO2 to formic acid and other reduced species.[15] An example is artificial photosynthesis with a graphene-based photocatalyst that is then coupled with a biocatalyst.15
Materials and Methods
Results
Discussion
Conclusion
References
3
[1] Solar Synthesis: Prospects in Visible Light Photocatalysis. D. M. Schultz, T. P. Yoon, Science 2014, 343, 1239176.
[2] “Light.” Merriam-Webster. 2015. Web. 30 Jan. 2015 <http://www.merriam-webster.com/dictionary/light>
[3] "Solar." EIA Energy Kids. Web. 31 Jan. 2015. <http://www.eia.gov/kids/energy.cfm?page=solar_home>.
[4] Otanicar, T.; Golden, J. Environmental Science & Technology 2009, 43, 6082–6087.
[5] SEIA http://www.seia.org/policy/solar-technology/concentrating-solar-power (accessed Jan 31, 2015).
[6] Solar Photovoltaic Cells. Mickey, C. J. Chem. Educ. 1981, 58, 418-423.
[7] Wallington, T. J.; Anderson, J. E.; Mueller, S. A.; Morris, E. Kolinksi; Winkler, S. L.; Ginder, J. M.; Nielsen O. J. Corn Ethanol Production, Food Exports, and Indirect Land Use Change. Am. Chem. Soc. 2012, 46, 6379-6384.
[8] “Photocatalysis.” Merriam-Webster. 2015. Web. 30 Jan. 2015 <http://www.merriam-webster.com/medical/photocatalysis>
[9] Green Earth Nano Science. N.p., 2014. Web. 30 Jan. 2015. Inc.<http://www.greenearthnanoscience.com/what-is-photocatalyst.php>
[10] Basic Functions of Photocatalyst. Web. 31 Jan 2015 <http://www.tipe.com.cn/library/kb2503.htm>
[11] Ângelo, J.; Andrade, L; Luís, M. M.; Adélio M. J. Environm. Managem. 2013, 129, 522-539.
[12] Photocatalytic Hydrogen Production by Direct Sunlight: A Laboratory Experiment. Koca, A.; Sahin, M. J. Chem. Educ. 2003, 80, 1314-1315.
[13] Xu, C.; Yang, W.; Guo, Q.; Dai, D.; Chen, M.; Yang, X. J. Am. Chem. Soc. 2014, 136, 602–605.
[14] “Biomass.” Merriam-Webster. 2015. Web. 31 Jan. 2015
[15] Yadv, Rajesh K.; Baeg, Jin-Ook; Oh, Gyu Hwan; Park, No-Joong; Kong, Ki-jeong; Kim, Jinheung; Hwang, Dong Won; Biswas, Soumya K. A Photocatalyst-Enzyme Coupled Artificial Photosynthesis System for Solar Energy in Production of Formic Acid from CO2 J. Am. Chem. Soc. 2012, 134, 11455-11461.