Talk about science and technology, then we are faced with such a field with fertile soil, with a variegated plant seedlings are ready we planted. Science and technology as it is endless to studied and researched. One of the technologies that are being developed in the last few decades is the technology fotokatalis.
Photocatalyst (photo-catalyst) is a catalyst that can be used to speed up chemical reactions that require or need the rays/light. Photocatalystis a material that has the ability to absorb light and electron-hole pairs produced (e-+ h +) which is able to perform a chemical transformation through the process of reduction and oxidation (Yeong Chan, Wu, Juan, & tea, 2011). The electron and hole pairs act as active agents play a role in determining the reaction process that will take place, whether in a State of oxidation or reduction. When the molecules meet with hole (h +) then the process that is taking place is the oxidation process where instead if the molecules in contact with electrons (e-) that excited, then the process that takes place is a process of reduction. However, it should be noted that the process of the reaction can only take place when electron and hole migrate to the surface of the material and contact with the target molecule quickly. Reaction process would never have happened if the recombination of electrons and holes caused by the release of energy (heat) by material.
Figure 1. The mechanism of the activation process of material fotokatalis
Source: (Hui Pan, 2016) modified in accordance with the interpretation of the authors
In the process, the material absorbs a photon of energy fotokatalis of the source beam and then convert it into chemical energy for use in various chemical reactions. This material is also considered as one of the technologies that are environmentally friendly (green technology) because of the potential to harness the Sun for use in some applications (M. P. V. k. Anpo, 2010). Characteristics of the absorbing material made the fotokatalis beam very potentially applied in Indonesia because Indonesia is a tropical country with the intensity of the Sun which is quite high. The combination of the intensity of the Sun is high and material fotokatalis with high activity can become a future technology that can be used in Indonesia.
In General, material fotokatalis is a semiconductor material which some research also reported that some of the organic compounds also have the ability to be used as fotokatalis materials (Vyas, Lau, & Lotsch, 2016). Titanium dioxide (TiO2) is a material fotokatalis the most widely researched to be applied in a variety of applications (Shan, Ghazi, & Rashid, 2010).
In its application, fotokatalis material can be applied in various aspects like process of industrial and agricultural waste management (Gupta & Tripathi, 2011), the process of disinfection in drinking water (Gamage McEvoy & Zhang, 2014), chemical synthesis (Uddin et al., 2012 ), gas sensors (Suman, Felix, Tuller, Varela, & Orlandi, 2015), and the production of hydrogen (Chen, Wu, Wu, & Tsai, 2011). Some applications have started to be developed into industrial scale, among others, the use of TiO2 fotokatalis material as the active material in the paint of the walls to keep the paint colors remain bright and help the process of purification of indoor air (Auvinen & Wirtanen, 2008). Basically, the use of fotokatalis materials in paint used to degrade organic molecules which stick to the paint or contained in the air in the room. When the paint is exposed by the rays of the Sun, then fotokatalis material contained on teraktifkan and thermally will paint any organic molecules which stick or come into contact with the cat, so the color of the paint will remain bright and durable (Figure 2). For info on the use of the material in the TiO2 paint can be seen at icis.com.
Figure 2. Illustration of the use of fotokatalis materials as the active ingredient in wall paints
Recently, researchers from the University of Antwerp in Belgium has created a tool that is able to purify the contaminated air using sunlight while producing hydrogen, stored and used for energy sources (Figure 3). They claim to use material light-activated catalyst as smart materials that work to run two processes. Basically, material fotokatalis they use to apply the principle of oxidation and reduction simultaneously where in the process of clearing the air, fotokatalis oxidation process of applying materials through holes (h +) that are produced, and production process hydrogen, fotokatalis oxidation process of applying materials through Electron (e-) that excited.
A very unique material characteristics make this material as a very promising materials to be applied in the future. The process of research-based materials fotokatalis continue to do until this moment, the majority of research based on optimization of material and process engineering can be optimum utilizing characteristics of the material can be used for fotokatalis in a variety of applications. We hope that someday this material can be one of the technologies that can be applied in Indonesia.
Reference
- Anpo, M. P. V. K. (2010). Environmentally Benign Photocatalysts. (M. Anpo & P. V. Kamat, Eds.). New York, NY: Springer New York. https://doi.org/10.1007/978-0-387-48444-0
- Auvinen, J., & Wirtanen, L. (2008). The influence of photocatalytic interior paints on indoor air quality. Atmospheric Environment, 42(18), 4101-4112. https://doi.org/10.1016/j.atmosenv.2008.01.031
- Chan, S. H. S., Yeong Wu, T., Juan, J. C., & Teh, C. Y. (2011). Recent developments of metal oxide semiconductors as photocatalysts in advanced oxidation processes (AOPs) for treatment of dye waste-water. J Chem Technol Biot, 86(9), 1130-1158. https://doi.org/10.1002/jctb.2636
- Chen, J.-J., Wu, J. C. S., Wu, P. C., & Tsai, D. P. (2011). Plasmonic Photocatalyst for H 2 Evolution in Photocatalytic Water Splitting. The Journal of Physical Chemistry C, 115(1), 210-216. https://doi.org/10.1021/jp1074048
- Gamage McEvoy, J., & Zhang, Z. (2014). Antimicrobial and photocatalytic disinfection mechanisms in silver-modified photocatalysts under dark and light conditions. Journal of Photochemistry and Photobiology C: Photochemistry Reviews, 19, 62-75. https://doi.org/10.1016/j.jphotochemrev.2014.01.001
- Gupta, S. M., & Tripathi, M. (2011). A review of TiO2 nanoparticles. Chinese Sci. Bull., 56(16), 1639-1657. https://doi.org/10.1007/s11434-011-4476-1
- Pan, H. (2016). Principles on design and fabrication of nanomaterials as photocatalysts for water-splitting. Renew Sust Energ Rev, 57, 584-601.
- Shan, A. Y., Ghazi, T. I. M., & Rashid, S. A. (2010). Immobilisation of titanium dioxide onto supporting materials in heterogeneous photocatalysis: A review. Applied Catalysis A: General, 389(1-2), 1-8. https://doi.org/10.1016/j.apcata.2010.08.053
- Suman, P. H., Felix, A. A., Tuller, H. L., Varela, J. A., & Orlandi, M. O. (2015). Comparative gas sensor response of SnO2, SnO and Sn3O4 nanobelts to NO2 and potential interferents. Sensors and Actuators B: Chemical, 208, 122-127. https://doi.org/10.1016/j.snb.2014.10.119
- Uddin, M. T., Nicolas, Y., Olivier, C., Toupance, T., Servant, L., MA?ller, M. M., Jaegermann, W. (2012). Nanostructured SnO2-ZnO Heterojunction Photocatalysts Showing Enhanced Photocatalytic Activity for the Degradation of Organic Dyes. Inorg Chem, 51(14), 7764-7773. https://doi.org/10.1021/ic300794j
- Vyas, V. S., Lau, V. W., & Lotsch, B. V. (2016). Soft Photocatalysis: Organic Polymers for Solar Fuel Production. Chemistry of Materials, 28(15), 5191-5204. https://doi.org/10.1021/acs.chemmater.6b01894
