Researchers from MIT and Harvard have pioneered an innovative process to efficiently convert carbon dioxide into formate, a versatile fuel substitute. This groundbreaking method surpasses traditional conversion techniques, achieving over 90% efficiency while avoiding toxic or flammable byproducts. Formate, produced from common industrial chemicals, remains non-toxic, nonflammable, and easy to store for extended periods. The process harnesses renewable energy sources, offering a sustainable solution for power generation. This innovation has the potential to transform emissions-free energy production, from individual homes to industrial applications.
In the quest for sustainable energy solutions, scientists have long sought ways to extract carbon dioxide (CO₂ ) from the atmosphere or industrial emissions and convert it into a useful substance. Among these endeavors, the creation of a stable fuel capable of replacing fossil fuels in specific applications has shown great promise. However, previous conversion methods have grappled with issues of low carbon efficiency or the production of hazardous, hard-to-handle, or flammable fuels.
In a significant breakthrough, a collaborative team of researchers from the Massachusetts Institute of Technology (MIT) and Harvard University has unveiled a highly efficient process that transforms CO₂ into formate. Formate is a liquid or solid material that can serve as a versatile fuel, akin to hydrogen or methanol, to power fuel cells and generate electricity. Notably, potassium or sodium formate, which is already produced on an industrial scale for applications such as de-icing roads, exhibits non-toxic, nonflammable, and stable properties. It can be safely stored in ordinary steel containers for months or even years after production.
This pioneering process, developed by MIT and Harvard researchers, including doctoral students Zhen Zhang, Zhichu Ren, and Alexander H. Quinn, Harvard University doctoral student Dawei Xi, and MIT Professor Ju Li, is detailed in the journal Cell Press Physical Sciences. While initially demonstrated at a laboratory scale, the researchers anticipate its scalability for emissions-free heat and power generation in individual homes and industrial or grid-scale applications.
Unlike traditional methods that involve a two-stage process, this innovative approach achieves a conversion rate of over 90% without the need for inefficient heating. Instead, it first converts CO₂ into a liquid metal bicarbonate, an intermediate form. This liquid is subsequently electrochemically converted into liquid potassium or sodium formate using low-carbon electricity sources like nuclear, wind, or solar power. The resulting highly concentrated liquid formate solution can be dried to produce a stable powder that remains viable for years in standard steel containers.
The key to this exceptional efficiency lies in a carefully designed membrane system that maintains a steady pH balance, ensuring continuous, stable conversion without compromising efficiency. In extensive testing, the process operated for over 200 hours with consistent output. Importantly, this entire process can be conducted at ambient temperatures and relatively low pressures.
Another critical factor addressed by the researchers was the prevention of unwanted side reactions that produce non-useful byproducts. They successfully introduced an additional "buffer" layer of bicarbonate-enriched fiberglass wool to mitigate these side reactions.
Moreover, the team designed a fuel cell optimized for using formate fuel to generate electricity. Formate particles, stored as solids, are easily dissolved in water and fed into the fuel cell as needed. Despite the solid fuel's higher weight compared to pure hydrogen, when considering the weight and volume of high-pressure hydrogen storage tanks, the result is nearly equivalent electricity output for a given storage volume.
The potential applications of formate fuel are vast, ranging from individual homes to large-scale industrial and grid-based storage systems. Initial household setups could include a refrigerator-sized electrolyzer unit to capture and convert CO₂ into formate, which would then be stored in underground or rooftop tanks. When required, the powdered formate could be mixed with water and fed into a fuel cell to supply power and heat. Beyond homes, this technology holds promise for industrial and grid-scale implementations.
The groundbreaking research conducted by MIT and Harvard paves the way for a revolutionary approach to combat climate change by converting CO₂ into a stable and versatile formate fuel. This innovation offers a sustainable path to emissions-free energy production, transforming the landscape from individual households to industrial and grid-scale applications.