As written in the journal Nano Letters, there is a new method discovered in reducing carbon emissions and converting it into useful materials. Research team from the U.S. Department of Energy (DOE)’s Lawrence Berkeley National Laboratory (Berkeley Lab) and the University of California (UC) Berkeley have disclosed an innovative technique that modify carbon emissions into highly advantageous chemical products like liquid fuel, biodegradable plastic materials and pharmaceutical products by employing carbon dioxide emissions and making use of solar energy and artificial photosynthesis— which marks the advancement in the artificial photosynthesis and carbon capture and storage. It utilizes carbon dioxide and water to produce acetate that is transformable to many important substances just like plants using sunlight to convert carbon dioxide and water into carbohydrates.
“We believe our system is a revolutionary leap forward in the field of artificial photosynthesis. Our system has the potential to fundamentally change the chemical and oil industry in that we can produce chemicals and fuels in a totally renewable way, rather than extracting them from deep below the ground,” said Peidon Yang, a chemist in Berkeley Lab’s Materials Sciences Division and one of the study leaders.
Highly knowledgeable in catalysts for carbon-neutral energy conversions, Chris Chang of Berkeley Lab and UC Berkeley, explained “In natural photosynthesis, leaves harvest solar energy and carbon dioxide is reduced and combined with water for the synthesis of molecular products that form biomass. In our system, nanowires harvest solar energy and deliver electrons to bacteria, where carbon dioxide is reduced and combined with water for the synthesis of a variety of targeted, value-added chemical products.”
The research team came up with an “artificial forest” made out of silicon and titanium oxide nanowire materials. Yang stated “Our artificial forest is similar to the chloroplasts in green plants. When sunlight is absorbed, photo-excited electron−hole pairs are generated in the silicon and titanium oxide nanowires, which absorb different regions of the solar spectrum. The photo-generated electrons in the silicon will be passed onto bacteria for the CO2 reduction while the photo-generated holes in the titanium oxide split water molecules to make oxygen.”
Using this method, the forest is colonized with microbes that activate the carbon dioxide reduction. The team utilized the anaerobic bacterium Sporomusa ovata to reduce carbon dioxide by applying electron from its surrounding. Michelle Chang, considered an expert in biosynthesis concluded “S. ovata is a great carbon dioxide catalyst as it makes acetate, a versatile chemical intermediate that can be used to manufacture a diverse array of useful chemicals. We were able to uniformly populate our nanowire array with S. ovata using buffered brackish water with trace vitamins as the only organic component.”
After the reduction of carbon dioxide has been carried out , the genetically engineered E. coli will combine the specific chemical products. The steps of S. ovata and E. coli could be synthesized eventually in the future according to the research team. Yang stated “We are currently working on our second generation system which has a solar-to-chemical conversion efficiency of three-percent. Once we can reach a conversion efficiency of 10-percent in a cost effective manner, the technology should be commercially viable.”