Carbon dioxide can be used to make plastics? You heard it right!

Author: Li Chuanfu Shi Xiangqi

As the global climate change problem becomes increasingly serious, how to effectively utilize carbon dioxide has become an important topic of scientific research. Previously, Chinese scientists have achieved the synthesis of starch from carbon dioxide. Recently, scientists published another breakthrough study in the journal Nature Synthesis, demonstrating an innovative method for converting carbon dioxide into bioplastics.

Electrochemical CO2 reduction is a technology that uses electricity generated from renewable energy to convert CO2 into high-value products. This approach not only reduces atmospheric CO2 concentrations, but also produces useful chemicals such as acetic acid, ethanol, and n-propanol. However, the process becomes more complicated when the goal is to produce products with carbon chain lengths longer than four carbons.

Biosynthetic systems are capable of converting CO2 or its derivatives into long-chain carbon fuels and chemicals, such as n-butanol and polyesters. However, when these systems are fed directly with CO2 or products of low-quality CO2 reduction reactions, their energy efficiency and carbon utilization may be reduced, which limits the economic and practical feasibility of these processes.

To overcome these challenges, scientists have proposed a method to optimize the integration of electrochemical CO2 reduction reaction with biosynthesis. This method can efficiently convert CO2 into longer and higher-value carbon products. Acetate is an ideal carbon source because it can be efficiently converted into high-value products by bacteria in bioreactors.

In this study, scientists developed a porous solid electrolyte reactor that can produce acetate with high selectivity and electrolyte-free. This reactor is coupled with a biosynthetic system to produce polyhydroxybutyrate bioplastics. This bioplastic is a degradable plastic that is of great significance in reducing plastic pollution.

Schematic diagram of the reactor integration platform Source: Nature Synthesis

The key innovation of this integrated platform is the ability to generate acetate in a biocompatible electrolyte medium, which is directly used in the biosynthetic process to produce polyhydroxybutyrate bioplastics, thereby achieving seamless integration of the two systems without the need for additional separation or pH adjustment steps. A silver-doped cuprous oxide nanocube catalyst was used in the study, which showed the ability to generate acetate with high selectivity in the electrocatalytic reaction. The selective generation of acetate during the electrochemical reduction process was achieved by the optimized silver-doped cuprous oxide catalyst.

This research provides a new method for converting carbon dioxide into useful chemicals and materials. By integrating the electrochemical carbon dioxide reduction reaction with biosynthesis, scientists not only improved the efficiency of carbon dioxide utilization, but also provided an effective way to produce sustainable bioplastics. The success of this technology demonstrates the potential of interdisciplinary collaboration in solving global problems and provides us with a new perspective on carbon dioxide - it is not only the culprit of climate change, but can also be an important raw material for making useful products. With the further development and optimization of the technology, we can expect to see more innovative ways to utilize carbon dioxide and contribute to the realization of green and sustainable development.