Photocatalysis is a revolutionary technology that uses light to break down and sterilize pollutants and can be used in a variety of applications, including air and water purification and self-cleaning surfaces. Advances in this technology will play an important role in creating a sustainable environment, and the possibilities for the future are enormous.
On the day my family decided to do a deep clean, we lifted the sofa and found a lot of dust on the floor, which was previously invisible, and we all realized how quickly dust accumulates. When Namjae shined a strong light with a flashlight, the dust slowly began to disappear, and within a few minutes, the floor was clean. The scene seemed unreal, like something out of a science fiction movie, but it might actually be possible with photocatalysts.
A photocatalyst is a substance that catalyzes in the presence of light, meaning that it accelerates chemical reactions in the presence of light, while not consuming itself in the process. This technology has been attracting attention as an important key to solving environmental problems with the development of modern science. In particular, titanium oxide (TiO2), a representative photocatalytic material, allows us to learn the secrets of photocatalysis.
How photocatalysis works
The principle of photocatalysis is surprisingly simple and powerful. The weapon of the “light army” that fights against the dirt and bacteria on your dishes is water vapor in the air. Like a gun loaded with bullets, water vapor sticks to the surface of TiO2. When sunlight hits it, the water vapor reacts like a gun trigger, producing OH radicals and free radicals. OH radicals and free radicals are a type of radical and are very unstable because they have an unpaired electron (hole electron). This instability contributes to their immediate reaction with the surrounding substances, breaking down pollutants into water and carbon dioxide. Interestingly, titanium oxide itself is not consumed in this process. As a result, as long as water is available, this purification reaction can continue indefinitely, which is one of the reasons why photocatalytic technology is gaining prominence in the field of environmental purification.
Photocatalysis – the next green technology
Another reason why photocatalysis is the next big thing in green technology is its ability to convert pollutants into environmentally friendly substances. Photocatalysts can decompose livestock wastewater, sewage, factory wastewater, environmental hormones, etc. into water and carbon dioxide, and turn them into substances that do not harm the environment. They also have the ability to sterilize more than 99.9% of pathogens and bacteria such as pathogenic E. coli, Staphylococcus aureus, and O-157 without raising the temperature. In the future, we will be able to live in a cleaner environment thanks to these technologies. In fact, photocatalytic technology is not affected by the weather, as it can absorb UV light and maintain its efficiency even in cloudy weather. Advances in photocatalytic technology will bring us a greener future than we can imagine.
Applications of photocatalysis – a jack-of-all-trades
Photocatalysts have many different uses. First, they can be used to remove pollutants. For example, using photocatalysts to treat factory wastewater or livestock wastewater can naturally remove harmful substances from the wastewater. This technology is also useful for air purification in hospitals or for removing harmful chemicals that cause sick building syndrome. When dirt accumulates on the surface of solar cells, it lowers the light transmission rate and reduces the efficiency of power generation. Second, they can be used to break down moisture on surfaces. Photocatalysts can be used to prevent frost from forming on windows in winter, or to protect electronic devices that should not be exposed to water. It can also be used in hydrogen production processes. Third, their ability to absorb ultraviolet light can be used to protect the interior of UV-sensitive objects. As you can see, photocatalysis is a versatile technology that can fulfill several roles simultaneously.
Photocatalysis. Still a long way to go!
However, photocatalysis is not a one-size-fits-all solution. Currently developed photocatalysts are not diverse and need to be improved in terms of pollutant tolerance and economics. In particular, there is an urgent need to develop inexpensive photocatalysts that can be mass-produced. There is also a problem that the purification range is somewhat limited. However, various research efforts are underway to address these issues. For example, alloys of titanium oxide with other metals are being developed to improve resistance, and zeolites are being mixed to broaden the purification range.
The future of photocatalytic technology. The potential is there
The outlook for photocatalytic technology is very bright. According to a recent market analysis, the photocatalyst market was valued at approximately $9.388 billion in 2022 and is expected to grow at a CAGR of 5.2% through 2030 to reach approximately $14.824 billion. Demand is expected to increase significantly, especially in the construction and environmental purification sectors, and its use in various applications such as air and water purification and self-cleaning surfaces is expected to expand. Technologically, titanium dioxide (TiO2) remains the most widely used photocatalytic material, and research and development is ongoing. If these research and technology developments are successful, it will only be a matter of time before photocatalysts make a significant difference in our daily lives. Moreover, with active investment from governments and private companies, the commercialization of this technology will be accelerated.
In conclusion, photocatalysis is still in its infancy, but it has great potential. As the technology is further developed and commercialized, photocatalysis will play an important role in improving the quality of our lives. The changes that photocatalysis will bring may soon become part of our everyday lives.
