Artificial photosynthesis breakthrough could turn CO2 into plastics on the cheap

From fuels, to foam mattresses, to high-performance carbon fibers, scientists are getting better all the time at capturing harmful CO2 and turning it into useful products. Researchers at Rutgers University have made an exciting breakthrough in this area, describing a new method of artificial photosynthesis that can convert carbon dioxide into the building blocks for plastics and other materials, and do so with greater efficiency and much more cheaply than ever before.

The ability of natural plants to take just a small amount of energy from the Sun to convert carbon dioxide into fuels, in their case carbohydrates and fats for self-sustenance, has inspired countless lines of clean-energy-oriented research. Recreating this process of photosynthesis in manmade devices is seen as a holy grail of sorts, and we have seen plenty of promising experimental devices that use photosynthesis to produce fuels we humans can use, such as methanol, methane and hydrogen.

But there is a ways to go before these technologies become commercially feasible, with their efficiency and costs closely tied to the catalyst materials used to kick off the chemical reactions. And this is where the Rutgers researchers are claiming to have taken a significant step forward, unearthing a set of catalyst materials that are widely abundant (and therefore cheap), and marry the low-energy requirements of natural photosynthesis with the durability needed to withstand harsh chemical reactions.

"The discovery of this catalyst came out of the efforts of applying nature's principles to chemical reactions of industrial importance," study co-author Anders Laursen explains to New Atlas. "This bio-inspired approach has the potential to leverage the low energy consumption of natural systems optimized through millions of years evolution but introducing the chemical resilience of heterogeneous catalysts. Through this we identified the family of nickel phosphides as excellent candidates for the CO2 reduction reaction, and we designed new reactors and analytical tools to verify our hypothesis."

The team's five new catalysts are made from cheap and abundant nickel and phosphorous, and the recipes can be tweaked to create carbon atom chains of varying lengths with more than 99 percent efficiency. These atoms can then take the form of molecules or long polymer chains, the latter of which can serve as the building blocks for plastics, potentially displacing the petroleum that is currently used in that process.

"Our breakthrough could lead to the conversion of carbon dioxide into valuable products and raw materials in the chemical and pharmaceutical industries," says lead author Charles Dismukes.

The scientists point out that it is hard to make direct cost comparisons with current methods where petroleum is used to produce plastics, as those numbers are a "highly guarded secret." They can draw conclusions regarding the efficiency, however, something that is measured in "overpotentials."

"The low overpotentials in this work means that the process is highly energy efficient, that is does not require a lot of energy," Laursen tells us. "Conventional electrocatalysts require up towards 0.7 V of overpotentials whereas this process reduces this loss by a factor of 70. The energy losses are essentially extra electricity that one has to use for the reaction. Hence, less energy means reducing the amount of electricity used and therefore the corresponding cost per kilogram (or pound) of product."

With patents in hand, the team will now work toward commercializing the technology. That will involve investigating the underlying chemical reaction to see how it could be tweaked to create other products, such as diols and hydrocarbons, along with how the technology can be scaled up from a laboratory setting to produce kilograms of useful materials every day.

The research has been published in the journal Energy & Environmental Science.

Source: Rutgers University