Breakthrough Titanium Compounds Double Carbon Capture Efficiency

Scientists have synthesized molecules using titanium peroxides to capture carbon dioxide, advancing direct air capture technology.

Their findings suggest that titanium-based compounds could offer a more affordable and efficient solution for carbon capture compared to older methods.

Breakthrough in Carbon Capture Technology

Researchers at Oregon State University have synthesized new molecules that efficiently capture large amounts of carbon dioxide from the air — a crucial step in fighting climate change.

Their work centers on titanium peroxides and builds on previous research into vanadium peroxides. This study is part of a broader federal initiative aimed at creating innovative methods and materials for direct air capture (DAC) of carbon dioxide, a major contributor to global warming caused by burning fossil fuels.

The research, led by May Nyman and Karlie Bach from OSU’s College of Science, was published on December 12 in Chemistry of Materials.

Enhancing Direct Air Capture

In 2021, Nyman, the Terence Bradshaw Chemistry Professor in the College of Science at OSU, was selected to lead one of nine direct air capture projects funded by a $24 million Department of Energy investment. Her team is studying how certain transition metal compounds react with air to extract carbon dioxide and convert it into stable metal carbonates, similar to naturally occurring minerals.

Transition metals are located near the center of the periodic table and their name arises from the transition of electrons from low energy to high energy states and back again, giving rise to distinctive colors.

Facilities that filter carbon dioxide from the air are still in their infancy. Technologies for mitigating carbon dioxide at the point of entry into the atmosphere, such as at power plants, are more mature. Both types of carbon capture will likely be needed if the Earth is to avoid the worst outcomes of climate change, the scientists say.

At present, there are a combined 18 active direct air capture plants operating in the United States, Canada, and Europe, with plans for an additional 130 around the globe. Challenges to direct air capture include big costs and high energy requirements compared to working with industrial exhausts. Additionally, the atmosphere’s concentration of carbon dioxide, four parts per million, is low, challenging the performance of carbon capture materials.

Cost-effective and Efficient Carbon Capture Solutions

“We opted to look into titanium as it’s 100 times cheaper than vanadium, more abundant, more environmentally friendly and already well established in industrial uses,” said Bach, a graduate student in Nyman’s lab. “It also is right next to vanadium on the periodic table, so we hypothesized that the carbon capture behavior could be similar enough to vanadium to be effective.”

Bach, Nyman and the rest of the research team made several new tetraperoxo titanate structures – a titanium atom coordinated with four peroxide groups – that showed varying abilities to scrub carbon dioxide from the air. Tetraperoxo structures tend to be highly reactive because of the peroxide groups, which are potent oxidizing agents.

Related peroxotitanates have been studied for their potential uses in catalysis, environmental chemistry, and materials science. However, the tetraperoxotitanates in this study had never been definitively synthesized; Bach was able to use inexpensive materials for high-yield chemical reactions.

“Our favorite carbon capture structure we discovered is potassium tetraperoxo titanate, which is extra unique because it turns out it is also a peroxosolvate,” Bach said. “That means that in addition to having the peroxide bonds to titanium, it also has hydrogen peroxide in the structure, which is what we believe makes it so reactive.”

The measured carbon capture capacity was about 8.5 millimoles of carbon dioxide per gram of potassium tetraperoxo titanate – roughly double that of vanadium peroxide.

“Titanium is a cheaper, safer material with a significantly higher capacity,” Bach said.

Named for the titans of Greek mythology, titanium is as strong as steel but much lighter. It’s non-toxic, does not easily corrode, and is the ninth most abundant element in the Earth’s crust – found in rocks, soil, plants and even the human body in trace amounts.

Reference: “Tetraperoxotitanates for High-Capacity Direct Air Capture of Carbon Dioxide” by Karlie Bach, Eduard Garrido Ribó, Jacob S. Hirschi, Zhiwei Mao, Makenzie T. Nord, Lev N. Zakharov, Konstantinos A. Goulas, Tim J. Zuehlsdorff and May Nyman, 12 December 2024, Chemistry of Materials.
DOI: 10.1021/acs.chemmater.4c01795

Other Oregon State authors on the paper included assistant professors Tim Zuehlsdorff and Konstantinos Goulas, postdoctoral researcher Eduard Garrido Ribó, graduate students Jacob Hirschi, Zhiwei Mao and Makenzie Nord and crystallographer Lev Zakharov, interim manager of OSU’s X-Ray Diffraction Facility.

The Murdock Charitable Trust also supported this research through an instrument grant.

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