Against this backdrop, environmental researchers from Doshisha University, Japan led by Prof. Takuya Goto recently published a study in Electrochimica Acta on 10 July 2023 that demonstrated one such method for converting CO2 into multi-walled carbon nanotubes (MWCNT) using molten salts through sustainable electrochemistry. Their study was made available online on 22 April 2023, and included contributions from Dr. Yuta Suzuki from the Harris Science Research Institute and Mr. Tsubasa Takeda from the Department of Science of Environment and Mathematical Modeling.
Using a sustainable electrochemical technique, the research team facilitated the conversion of CO2 into MWCNT using LiCl-KCl melt. The molten salts were saturated with CO2 gas and semi-immersed nickel (Ni) substrate was used as electrode. The supplied CO2 was electrochemically converted to solid carbon at the end of the procedure. This green conversion occurred via a reduction reaction at the Ni electrode/LiCl-KCl melt/CO2 interface.
"The electrochemical reduction of CO2 on a Ni electrode in LiCl-KCl melt at 723 K was studied. Under high polarization, a super meniscus was formed at the three-phase interface of the Ni electrode/LiCl-KCl melt/CO2 gas, where the direct electrochemical reduction of CO2 to solid carbon progressed. Solid carbon was obtained in the wetted area of the Ni electrode as well as in the bulk molten salt via the electrochemical technique," remarks Prof. Goto.
Subsequent characterization of the electrode-deposited carbon using electron microscopy techniques and elemental analysis revealed that the obtained carbonaceous material consisted of MWCNTs, commercially viable nanostructures, that were 30 - 50 nm in diameter. The team then varied the applied voltage and extended the reaction time, recording noticeable changes in the MWCNTs. The height of the generated MWCNTs increased after the electrolysis time was increased from 10 min to 180 min. "We studied the dependence of applied potential and electrolytic time on the morphology and crystallinity of the electrodeposited carbon. Based on our experimental results, we proposed a model for the formation of the MWCNTs on the Ni electrode," highlights Prof. Goto.
The proposed model for the generation of MWCNTs from CO2 is described in three stages. The first stage involves the reduction of CO2 to carbon atoms at the Ni/LiCl-KCl melt/CO2 interface. During the second stage, the electrodeposited carbon atoms form Ni-C compounds (like NiC) on the surface of Ni electrode. Finally, when solubility limit of carbon in Ni-C compounds is reached, the cylindrical-shaped MWCNTs grow from the edge of the Ni-C compounds generated during the second stage.
In summary, the study identifies a novel process for sustainably converting CO2 into commercially useful carbonaceous materials. Moreover, the employed electrochemical process is environment friendly owing to the non-usage of fossil fuel. In addition, the use of high-temperature molten salts is unique because it enables the direct conversion of CO2 gas into MWCNTs.
"Our results indicate that CO2 can be converted into carbonaceous functional materials. By combining non-consumable oxygen-evolving anodes, this technique can contribute to the development of a carbon recycling technology that will not only solve global environmental problems but also play an important in carbon pricing economies. The material production process, which does not use fossil fuels, will help realize a sustainable society in the near future," concludes an optimistic Prof. Goto.
Research Report:Direct Electrochemical Formation of Carbonaceous Material from CO2 in LiCl-KCl Melt
Reader Relevance Scores:
Technology and Energy Industry Analyst: 8/10
Stock Market Analyst: 6/10
Industry Analyst: 7/10
Who Should Read This Article?
Technology and Energy Industry Analysts: They will benefit from understanding this innovative approach to carbon conversion, which can impact the energy sector, specifically those industries involving carbon capture technologies and renewable energy.
Stock Market Analysts: Those focusing on green technology or energy sectors would find this relevant as the innovation could change the landscape of these sectors and influence the value of related stocks.
Industry Analysts: Analysts involved in environmental, chemical, and materials industries could use this information to assess potential impacts on manufacturing processes and product development, especially in industries working with carbon-based materials or environmental technologies.
Analyst Summary:
The article discusses a groundbreaking method to convert CO2 into multi-walled carbon nanotubes (MWCNT), using molten salts through sustainable electrochemistry. The process is environmentally friendly due to non-usage of fossil fuel, and the MWCNTs are commercially viable materials. This study represents a potential shift in carbon recycling technology and can be significant for carbon pricing economies.
Historical Comparison:
Over the past 25 years, efforts to reduce CO2 emissions have been a key focus, with various methods like carbon capture and storage being explored. This study marks a significant advancement, as it not only tackles the problem of CO2 reduction but also transforms the gas into a commercially useful material. This reflects an ongoing trend toward sustainability, carbon recycling, and practical applications for 'waste' products.
Fact-finding Questions:
+ What is the efficiency and cost-effectiveness of this new process compared to existing CO2 reduction methods?
+ What is the market potential for the generated MWCNTs, and which industries would benefit most from this product?
+ What is the environmental impact of the process, particularly considering the use of high-temperature molten salts?
Related Links
Doshisha University
Carbon Worlds - where graphite, diamond, amorphous, fullerenes meet
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