On the cusp of a mass of discoveries about artificial photosynthesis, Panasonic Corporation has clipped the wings of several American consortia. Admittedly, they are also trying to make carbohydrate, while this process mainly mops up the gas causing global warming.
In all of these realms of the mimics of plant metabolism, it's all about catalysts. Catalysts first of all to break down the water and then to copy the action of the resultant hydrogen as it is used to reduce the carbon dioxide.
Relevance of course lies in the reduction of large amounts of CO2 but possibly in the further production of oxygen and the synthesis of foods. These are feasible with the "artificial leaf" systems being developed elsewhere, but the Panasonic method simply produces an organic acid.
In Osaka, Panasonic have announced the development of a system that changes carbon dioxide into organic substances at a 0.2% efficiency, which equals the plants' capabilities. A photo-electrode is used on a metal catalyst to perform the reduction with a nitride semiconductor. This excites electrons enough to cause a reaction proportional to the power of the light employed as there is little loss of energy.
Organic systems used to date just can't compete with this proportional reaction rate, as too much energy is absorbed. Focussed light can also be used instead of simply exposing the apparatus to general light. Presumably this could easily control the reaction so you could achieve exactly the amount of absorption required.
Schematic view of artificial photosynthesis system; Credit: © Panasonic Corporation
The unexpected product is formic acid. This can be used directly in industry, used for the manufacture of dyes and perfumes. And next on the agenda come the increasing number of piloting experiments in incinerators and generating plant to see how the scaled up versions perform in industry. The formic acid of course can be simply converted into many different substances, from its simple formula.
As you can tell, alcohols could be manufactured or many different formates could be made because of its acid properties. Alternatively, the future could easily suggest other organic products instead of the acid, leading to extensive carbohydrate production.