Tuesday the web started noticing that Panasonic has developed an artificial photosynthesis system, which converts carbon dioxide (CO2) to organic materials. A quick review of the web site commentary revealed how far the assumptions got before Panasonic got the press release open and out in English on the corporate site in Japan.
What Panasonic has developed is three major improvements in one process.
The first part is Panasonic has taken CO2 directly to formic acid, a valuable precursor to numerous petroleum like compounds including fuels. The next phase is the efficiency approximates that of many plants, 0.2%. Obviously, paving over areas that need shaded offers a much lower cost route to liquid fuels than soil, weather, plants, cultivation, and processing, etc.
The third part is the new technology is a simple and tough structure that could well stand up to light collection and focusing to high intensity.
That’s one very big jump indeed. No living molecules involved.
Panasonic’s artificial photosynthesis system converting carbon dioxide to organic materials by illuminating with sunlight is now a top world’s top efficiency of 0.2%. The efficiency level is on a comparable level with the plants commonly used for biomass energy.
The key to the system is the application of a nitride semiconductor, which makes the system simple and efficient. This development will be a foundation for building a system for capturing and converting wasted carbon dioxide from incinerators, power plants or industrial activities.
Previously, approaches to systems have had complex structures such as organic complexes or plural photo-electrodes, which makes it difficult to improve their efficiency in response to the light. Panasonic’s artificial photosynthesis system has a simple structure with highly efficient CO2 conversion, which can utilize direct sunlight or focused light.
Panasonic says they first found that a nitride semiconductor has the capability to excite the electrons with enough high energy for the CO2 reduction reaction. Nitride semiconductors have attracted attention for their potential applications in highly efficient optical and power devices for energy saving. However, its potential was revealed to extend beyond solid devices; more specifically, it can be used as a photo-electrode for CO2 reduction. Making a structure for a device through the thin film process for semiconductors, has highly improved the performance as a photo- electrode.
The CO2 reduction takes place on a metal catalyst at the opposite side of nitride semiconductor photo-electrode. See Fig. 1. The metal catalyst plays an important role in selecting and accelerating the reaction. Here, it is noted that the system is comprised of only inorganic materials, which can reduce the CO2 with low energy loss. Because of this, the amount of reaction products is exactly proportional to the light power. This is one of the merits in such an all-inorganic system, as some working conventional systems cannot follow a general powering up of the light power because of their internal or external rate-limiting processes in the complex structures.
The nitride semiconductor and a metal catalyst system generates mainly formic acid from the CO2 and water with light at a world’s top efficiency of 0.2%. The efficiency is comparable to the level of real plants used in the biomass energy source. Formic acid is an important chemical in industry, most commonly known for dye and fragrances.
The reaction rate is completely proportional to the light power due to the low energy loss with a simple structure; in other words, the system can respond to focused light. This will make it possible to design a simple and compact system for capturing and converting waste carbon dioxide from incinerators and electric generation plants.
That’s a bit repetitive, but follows the intent of the translated press release on the Panasonic site.
The schematic is quite tantalizing and revealing. Assuming the whole of the inputs and outputs are disclosed the process is consuming all desirable inputs and expelling no undesirable ones. There is sure to be more to all of this, but for now the folks at Panasonic have offered up a great leap of progress for using solar energy in a practical way.
The patent work is underway. Panasonic personnel presented the technology in part at 19th International Conference on the Conversion and Storage of Solar Energy held on Pasadena, United States on July 30, 2012.
OK. Congratulations, good work, keep it coming.