Can 3D Printing with Captured Carbon Help Address Climate Change?

It sounds almost too good to be true, but a recent study published in Nature Communications describes a potentially groundbreaking process where carbon dioxide (CO2) is converted into 3D-printed carbon nanocomposites. The integrated system could be a game-changer in the fight against climate change and also provide companies with the financial incentive they need to invest in carbon capture technologies.  

The Origin Story

This project, led by Dr. Kelvin Fu from the University of Delaware and Dr. Feng Jiao from the University of Washington, started with a simple yet ambitious goal: help mitigate carbon pollution while also crafting high-performance materials. But, how do you do both at the same time? Their solution: provide companies with a value-added product— carbon nanotubes (CNTs)— that can be made from CO2 captured directly from the atmosphere. By doing so, businesses will be incentivized to adopt carbon sequestration technologies in order to create the valuable material they want, and we get a cleaner environment in the process. 

Turning CO2 into Carbon Nanotubes

It starts with a two-step process. First, CO2 is pumped into the electrolysis machine where it interacts with a 200 cm2 electrolyzer stack. The stack, containing silver (Ag) cathodes, iridium (Ir) anodes, and a cesium bicarbonate (CsHCO3) electrolyte solution, reacts with the CO2  converting it into carbon monoxide (CO) and oxygen. Once generated, the CO is channeled into the thermochemical reactor where it then reacts with cost-effective steel wool. It’s here when the carbon monoxide dissociates on the steel wool catalyst and the CNTs begin growing. When the reaction is complete, the tubes can be harvested and are ready to be 3D printed. 

The combination system can run continuously for over 45 hours and create 37 grams of CNTs. It also drastically reduces the cost of manufacturing carbon nanotubes by nearly 90%, dropping it from $100 per kg to $9.50 per kg. The scientists even noted that with further improvements, this cost could theoretically be reduced even further to $6.00 per kg.

3D Printing Carbon Nanocomposites

To manufacture the 3D-printed carbon nanocomposites, the CNTs are incorporated into a PLA filament, which acts as a binder for the carbon nanotubes. The filaments are loaded to 40 wt% to increase maximum CO2 utilization and ensure the CNTs’ structural integrity after the PLA is removed. The filament is then 3D-printed into the desired shape, and the PLA is removed through a heating process. What is left behind is a scaffold made purely of CNTs. The scaffold can then be encased in another material, such as epoxy resin, to enhance the final product’s strength and durability.

In the paper, the researchers encased their 3D-printed CNT scaffold with epoxy resin, producing a material that was 38 wt% CNT. The resulting composite exhibited impressive improvements in both mechanical properties and electrical conductivity when compared to neat epoxy samples. They also showed the ability to 3D print complex shapes like a honeycomb structure and even a pig’s head.

What’s next?

The implications of this research are vast. Not only does it present a way to capture and repurpose atmospheric CO2, but it also opens the door to creating high-performance, sustainable materials for a variety of industries. As the technology continues to evolve, this process could provide an economical incentive to invest in carbon sequestration technologies and create better materials in parallel. While it’s too early to say if this will be the future of manufacturing, any innovation that helps tackle climate change while making production processes more sustainable is worth keeping an eye on.

The full article can be found here.