UCLA Chemical Engineers Find New Path To Improve Efficiency Of Plastic Precursor Production

Computational modeling shows new catalysts can produce propene with greater consistency while using less energy

Polypropylene is a lightweight and durable plastic found in common household products from food containers to storage bins. The conventional methods of producing its raw material, propene, however, rely on high energy input or costly platinum catalysts and often result in inconsistent yields.

Now, UCLA chemical engineers have mapped out a promising method to improve the conversion of propane gas into propene, the world’s second most widely produced plastic precursor, after ethylene.

Using computer simulations, the researchers found that an emerging class of chemical catalysts known as single-atom alloys could make the process more efficient, increasing yield while reducing energy use and material costs. A study describing their findings was published April 1 in the journal Chem Catalysis.

Propene is primarily produced through steam cracking and fluid catalytic cracking — industrial processes that heat hydrocarbons to temperatures exceeding 800 degrees Celsius to “crack” them into smaller molecules. While effective, these methods are energy intensive and produce a mixture of chemical byproducts.

An alternative method, known as propane dehydrogenation, operates at lower temperatures, around 600 degrees Celsius, and produces both propene and high-purity hydrogen. However, the process relies on platinum catalysts, which are costly and prone to “coking,” the buildup of carbon that clogs the catalyst surface, leading to performance degradation and periodic shutdowns for cleaning.

To address these limitations, the UCLA team used computer simulations to explore catalysts made from copper alloys containing small amounts of hafnium or iridium. Their simulations showed that these single-atom alloys can more efficiently catalyze the reaction than platinum-based systems while reducing coking.

In single-atom alloys, individual atoms of an active metal such as hafnium or iridium are dispersed across the surface of a host metal, in this case copper. This enables greater control over chemical reactions.

“What makes these copper-based single-atom alloys work is their structure. There is just enough active metal to carry out the reaction, but not so much that it creates waste or unwanted byproducts,” said study leader Philippe Sautet, a distinguished professor of chemical and biomolecular engineering at the UCLA Samueli School of Engineering and holder of the Levi James Knight, Jr. Term Chair for Excellence. “Replacing platinum with these materials could enable more efficient production of propene and hydrogen while limiting coke formation.”

According to the team’s modeling, the improved performance comes from the isolation of hafnium or iridium atoms, which enhances their ability to break hydrogen–carbon bonds in propane molecules. This enables a more controlled reaction that produces propene.

The findings are based on predictive computational modeling and will require experimental validation. Previous experimental studies have shown that single-atom catalysts can achieve high selectivity in propane-to-propene conversion. Further work will be needed to confirm the results and assess scalability for industrial use.

At UCLA, Sautet also holds a joint faculty appointment in the Department of Chemistry and Biochemistry and is a member of the California NanoSystems Institute.

The study’s co-author, Hio Tong Ngan, completed his doctorate in chemical engineering in 2024 under Sautet’s advisement and is now a research engineer in the energy industry.

The research was funded by the U.S. Department of Energy Office of Science. Computational resources were provided by the DOE National Energy Research Scientific Computing Center, the Pittsburgh Supercomputing Center and the UCLA Institute for Digital Research and Education.