Previously, we have talked about how scientists have devised an artificial photosynthesis system that and absorbs and converts carbon dioxide emissions into usable components. But this time around, beyond a complex system, researchers at Florida State University have created an artificial material that replicates the natural process of photosynthesis. The material in question here pertains to manganese oxide (or birnessite) and its advantageous capacity of capturing sunlight. This collected solar energy in turn can be used for an oxidation chemical reaction that would lead to the synthesis of H20 (water) into hydrogen (H) and oxygen (O2). In essence, the scope mimics the oxidation process of photosynthesis, which can potentially aid in generating fuel energy.
Initially, the scientists looked forth to identifying a material that would be optimized for capturing sunlight as well as for breaking down water. To that end, a low cost substance that can mitigate the effects of rusting when exposed to water was conducive to the process. So, as an all-round solution, the researchers came up with the notion of utilizing a multilayered material made of manganese oxide. But on further analysis they discovered that a single layer of the material was far effective in capturing the magnitude of sunlight with a higher rate.
The reason for this effectiveness relates to the provision of direct band gap by the single layer manganese oxide. But in its multilayered iteration, the material much like purified silicon, has indirect band gap – which is not at all conducive to absorbing light of any kind. In other words, the single layer material with its enhanced light capturing capacity, proved to be an unintentional benefit for the researchers, given its potentially cheaper and easier manufacturing process. This in turn alludes to commercial viability. As the press release suggests –
Light with photo energy can penetrate indirect band gap materials much more easily without getting absorbed and used for other purposes. Silicon, for example, is the most commonly known indirect gap band material. But to make the material effective, silicon solar cells are typically stacked and thus hundreds of micrometers thick. If they were any thinner, light would simply pass through them.
And the other major advantage of the artificial photosynthesis procedure is its connection to carbon-neutrality. Simply put, future energy sources like hydrogen fuels can be generated without any baleful effect on the environment, as opposed to conventional processes for producing hydrogen that use fossil fuels. As Jose L. Mendoza-Cortes, assistant professor of chemical engineering, made it clear –
In theory, this should be a self-sustaining energy source. Perhaps in the future, you could put this material on your roof and it could turn rain water into energy with the help of the sun.
Now at the end of the day, suffice it to say, this process of artificial photosynthesis is still in a developmental stage, with no actual word on its mass-scale availability. But with the advantage of chance (yet massive) efficiency quotient delivered by the single layer manganese oxide, we may look forth to effective commercial applications possibly in the near future.
The study was originally published in The Journal of Physical Chemistry.
Source: Florida State University