As one of the most important chemical processes on earth, photosynthesis makes it possible to directly store the sun’s energy. Until now, only plants and some other organisms have been able to photosynthesize. Now researchers at the Johannes Kepler University (JKU) Linz have also artificially re-created the process. For the first time, a research team led Prof. Günther Knör (head of the Institute of Inorganic Chemistry, JKU) has succeeded in taking an essential step towards fuel production and CO2 fixation using artificial photosynthesis.
A science team led by Prof. Knör (head of the Institute of Inorganic Chemistry and the Photochemistry Center at the JKU) has been able to show that everything green leaves need to convert sunlight to energy can be replaced by a combination of manmade dye molecules and catalysts. Dr. Kerstin Oppelt remarked, “Just as in plants, the energy storage material NAD(P)H can be formed.” This substance could never before be obtained under reaction conditions by exposure to artificial substances as it is in nature.
The results’ exact impact is currently unknown at the moment. In any case, NAD(P)H can be used without additional energy to develop other organic storage substances (like carbohydrates such as sugar or starch). At the same time, the greenhouse gas carbon dioxide is bound. Ultimately these subsequent processes form dark photosynthetic reactions which are the basis of our diet as well as our current energy supply of fossil fuels.
Prof. Knör explained: “The chlorophyll substitute we manufactured is much more stable than plant and algae chlorophyll. The biggest surprise, however, was when a detailed energy efficiency analysis was conducted. “We quickly realized that generating the chemical storage substance NAD(P)H in our newly developed artificial reaction center showed significantly less energy loss than the natural photosystem I (PSI) found in green plants!” The maximum energy light reaction yield of approximately 40% in PSI increased to almost 80% in the artificial photosystem. Prof. Knör added, “These first results are very promising and have attracted international attention in professional circles. Against a background of increasing population and soaring energy needs as well as climate problems, many scientists are trying to bio-chemically improve the efficiency of natural photosynthesis. Perhaps one day photosynthesis by using ‘artificial leaves’ will be a contender in the race.”
Artificial photosynthesis is at the center of renewable energy efforts to create a sustainable, environmentally friendly chemistry of the future. Using nature as a model, the biochemical, universally usable storage material NAD(P)H (or solar hydrogen as its technical-chemical equivalent) could be used to produce numerous other valuable products from simple raw materials.
Prof. Knör and his team and colleagues at the JKU are currently working successfully on the next step. Artificial photosynthesis can be used in the extraction of alcohol fuels. In the future, these and other similar processes could use sunlight, air and water to obtain renewable energy and food instead processes containing harmful CO2 emissions.