A team of researchers has established a new method of converting carbon dioxide (CO2) into oxygen (O2) and pure carbon monoxide (CO) without producing hydrogen gas (H2) and methane (CH4) as by-products. This innovative new strategy promises a method of artificial photosynthesis that could help solve the key issues of environmental pollution and global warming.
Improving on Nature’s Photosynthesis
In a paper published this month in the journal Materials Today, scientists at the Institute for Basic Science, South Korea, describe how they have developed a new method that improves on the natural process of converting CO2 into O2 by photosynthesis. In nature, this system uses light to transform CO2 and water into glucose and O2. However, the South-Korea based team demonstrate an artificial method that transforms CO2 into O2, producing only pure CO as a byproduct, which the team highlight can prove useful in its uses in electronics, semiconductors, pharmaceuticals, and chemical industries.
Finding the Right Catalyst is Key
Establishing a way to facilitate the flow of electrons was determined by the researchers as essential for enabling efficient photosynthesis to take place. This process, they realized, would be boosted by selecting the right high-performance photocatalyst. This is where the use of nanoparticles came into play.
Titanium oxide (TiO2) is a commonly used nanoparticle that acts as a photocatalyst. Currently, it has already proven its uses in applications in solar energy conversion and environmental protection. The nanoparticles are effective at absorbing UV light, however, two different types of blue-colored TiO2 (or "blue titania”) have previously been identified as being able to absorb visible light.
Nanoparticles of TiO2 are constructed of anatase/disordered rutile (Ao/Rd), and disordered anatase/ordered rutile (Ao/Rd) where anatase and rutile are two crystalline forms of TiO2 and the introduction of disorder in the crystal has the result of improving the absorption of both visible and infrared light. To facilitate an efficient form of artificial photosynthesis, the South Korea-based team enhanced the performance of the TiO2 nanoparticles by adding blue (Ao/Rd) TiO2 with along with other semiconductors and metals that have the impact of boosting water oxidation to oxygen.
An analysis of the data revealed that hybrid nanoparticles made of blue titania, tungsten trioxide (WO3), and 1% silver (TiO2/WO3–Ag) were the most effective at enhancing the process of artificial photosynthesis. Results showed that these hybrid nanoparticles that the team created performed 200 times better than the nanoparticles that were constructed from TiO2 alone or TiO2/WO3 without silver.
The team was able to demonstrate that in using these uniquely made nanoparticles to catalyze the reaction, water and CO2 was converted into O2 and pure CO, without providing any side products, like hydrogen gas (H2) or methane (CH4), for instance.
Using Artificial Photosynthesis to Address Global Warming
What the team has achieved with their development of an efficient method of artificial photosynthesis will have a positive impact on solving problems in environmental pollution and global warming. We are very aware of how there is an immediate need for CO2 levels to be tackled worldwide, and this system presents an opportunity to use sunlight to convert these harmful molecules back into useable oxygen, and pure CO that have a myriad of uses in different sectors.
The team presents a potential technique for working towards reducing the levels of emissions, helping to reduce the negative impacts of global warming. While further development of the technique is needed before it can be applied on a larger scale, it provides a promising avenue that will likely be used in the future alongside other techniques to tackle global warming.