Oak Ridge National Laboratory — ORNL
CONTACT Karen Dunlap

An innovative and sustainable chemistry developed at the Department of Energy’s Oak Ridge National Laboratory for capturing carbon dioxide from air has been licensed to Holocene, a Knoxville-based startup focused on designing and building plants that remove carbon dioxide from atmospheric air.

“ORNL is tackling climate change by developing numerous technologies that reduce or eliminate emissions,” said Susan Hubbard, ORNL deputy for science and technology. “But with billions of tons of carbon dioxide already in the air, we must capture carbon dioxide from the atmosphere to slow and reverse the effects of climate change.”

“Direct air capture allows us to collect legacy emissions,” said Radu Custelcean, a scientist in ORNL’s Chemical Sciences Division and inventor of the licensed technology. “Our technology is one of the few approaches that can do that. It offers a new, energy-efficient approach to removing CO2 directly from air.”

In direct air capture, a large fan pulls air through a contacting chamber where the air interacts with chemical compounds that filter and capture carbon dioxide. The CO2 can then be released from the capture material and stored deep underground.

Holocene’s founder and chief executive officer Anca Timofte said there are several chemical approaches to direct air capture, or DAC, each with benefits and drawbacks.

“ORNL’s chemistry combines the best features of existing approaches to DAC to create a water-based, low-temperature process,” she said.

Custelcean’s process uses an aqueous solution containing ORNL-discovered receptors called Bis-iminoguanidine, or BIGs, to absorb carbon dioxide. As this happens, BIGs turn into an insoluble crystalline salt, which can easily be separated from the liquid solution. Custelcean and his research team discovered this new chemistry by chance while conducting fundamental crystallization experiments. The resulting Bis-Iminoguanidine Negative Emission Technology, or BIG-NET, received an R&D 100 Award in 2021.

The BIGs discovery propelled Custelcean’s research in a new direction.

“Doing basic research under DOE’s Basic Energy Sciences program, I have the flexibility to change direction if I find something interesting,” Custelcean said. “The basic research allows us to better understand all the elementary reactions and processes involved. But through licensing, we get to see a progression with our partners in the development of the technology. We’re involved in the full spectrum of research.”

Timofte, originally from Romania, has a background in chemical engineering and worked at one of the world’s first direct air capture companies, Switzerland-based Climeworks. She contributed to the design of the company’s largest plant, which is in Iceland. With a growing interest in the market and finance aspects of carbon capture, she left Climeworks to enroll in the Master of Business Administration program at Stanford University to focus on climate technology and entrepreneurship.

Timofte avidly followed the published literature around carbon capture. Custelcean’s publications caught her eye — she recognized the name as being Romanian — and she saw how his chemistry could address the major hurdles of the two established direct air capture processes.

“The more I learned about his research, the more I saw the potential and the more I wanted to start my own company to pursue it,” she said. “With the encouragement of my professors, I founded Holocene and licensed the technology so I could work on it in a lab and think more about commercialization.”

With Holocene established and the ORNL technology licensed, Timofte is further developing her business plans through Innovation Crossroads, a DOE Lab-Embedded Entrepreneurship Program funded by DOE’s Advanced Materials and Manufacturing Technologies Office, Building Technologies Office and the Tennessee Valley Authority.

“When you’re in the position of starting a new company, having a group of mentors like the ones at Innovation Crossroads and the ability to work with ORNL is very appealing,” Timofte said. “I was happy to get into the program. It helps with the normal challenges that all startups have, but also very importantly, it connects us with the local ecosystem in Knoxville and gives us access to the scientists who developed the chemistry. We can work together and transfer knowledge — we can learn more about how the licensed technology works, work on features, troubleshoot issues, de-risk and optimize the chemistry. It’s a nice continuation of the collaboration.”

Innovation Crossroads provides Holocene with a two-year cooperative research and development agreement to continue working with Custelcean and ORNL. Through this partnership, Holocene staff learn more about the science behind the technology, troubleshoot issues in testing and scale-up and connect with mentors at the lab and in the community.

“Holocene is a great example of how the interconnected climate tech ecosystem can support a new company through the stages of development,” said Dan Miller, Innovation Crossroads program lead.

Timofte is a Breakthrough Energy Fellow, a program launched by Breakthrough Energy — which was founded by Bill Gates — focused on accelerating innovation in sustainable energy and other technologies to reach net-zero emissions by 2050. Holocene is also part of the Spark Incubator Program, an entrepreneurial support program at the University of Tennessee Research Park’s Spark Innovation Center.

Next up, Holocene and ORNL will conduct bench-scale testing funded by DOE’s Office of Fossil Energy and Carbon Management with the aim of using ORNL’s chemistry to further develop and deploy direct air capture at a commercial scale.

ORNL senior commercialization manager Alex DeTrana negotiated the terms of the license. For more information about ORNL’s intellectual property in chemicals, email ORNL Partnerships or call 865-574-1051. To connect with Holocene, complete this online contact form.

The invention development team includes ORNL’s Costas Tsouris, Gyoung Gug Jang and Diana Stamberga. Charles Seipp and Neil Williams, formerly of ORNL, also participated. Read more about Custelcean’s carbon-removal research work.

UT-Battelle manages ORNL for the Department of Energy’s Office of Science, the single largest supporter of basic research in the physical sciences in the United States. The Office of Science is working to address some of the most pressing challenges of our time. For more information, please visit