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Nanoshell catalysts turn greenhouse gases into useful chemicals

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Two studies by the University at Buffalo show promise for dry methane reforming, an industrial process that could slow the pace of climate change

BUFFALO, NY — A byproduct of landfilling, ranching, coal mining and other human activities, methane emissions are a major driver of climate change.

Yet for decades scientists have struggled to develop inexpensive ways to use methane – which is the main component of natural gas – without also producing carbon dioxide, the most abundant greenhouse gas. in the earth’s atmosphere.

Among the possible solutions is dry reforming, a process that has the potential to convert both methane and carbon dioxide into chemical feedstocks, which are raw materials that can be used to make or transform other products.

However, for dry reforming to become commercially viable, new and improved catalysts are needed.

In two studies led by the University at Buffalo published in June – one in Chemical catalysisthe other in Angewandte Chemie – researchers report a new production method for creating nickel-based catalysts that could overcome long-standing challenges.

“To achieve the goals of the Paris Agreement, to achieve carbon neutrality, we need to implement many changes in both energy production and chemical feedstock production,” says the lead author. of Studies, Mark Swihart, PhD, SUNY Professor Emeritus and Department Chair. of Chemical and Biological Engineering at the UB Faculty of Engineering and Applied Sciences.

Shuo Liu, a doctoral student in Swihart’s lab, is the first author of the studies.

Co-authors with ties to UB include Satyarit Rao, Mihir Shah, Jilun Wei, Kaiwen Chen, and Zhengxi Xuan; as well as Eleni A. Kyriakidou, PhD, assistant professor of chemical and biological engineering at UB, and Junjie Chen, PhD, postdoctoral researcher at Stanford University who earned a doctorate in Kyriakidou’s lab.

Other co-authors include Jeffery J. Urban, PhD, director of the Inorganic Nanostructures Facility at Lawrence Berkeley National Lab’s Molecular Foundry, and Chaochao Dun, PhD, postdoctoral researcher at Urban’s lab.

Swihart explains that dry methane reforming is not commercially viable using existing nickel-based catalysts, which stop working because their catalytically active particles become coated with carbon deposits (coking) or combine into larger particles. large and less active (sintering). The most promising catalysts also require complex production procedures.

To address this problem, the research team developed a one-step aerosol process to manufacture low-cost, high-performance catalysts. The process is based on a single-flame reactor developed in Swihart’s lab.

The team used the reactor to create tiny spherical particles called nanoshells that resist both coking and sintering.

In the Chem Catalysis study, the team reported that over the course of 500 hours, the catalysts remained efficient, converting 98% of the methane into syngas, or syngas, which is a mixture of hydrogen and monoxide. of carbon which can then be used to produce a variety of chemicals.

In a second study, the team used the reactor to produce a new mesoporous silica material with a surface area exceeding 1,000 square meters per gram. The team also created a method to deposit nickel or other nanoparticles into mesoporous silica – a process known as in situ deposition.

As reported in Angewandte Chemie, the mesoporous silica catalyst converted 97% of the methane for over 200 hours.

This breakthrough, Swihart says, paves the way not only for improved catalysts for the dry reforming of methane, but also for many other environmentally and economically beneficial reactions.