Researchers from Nanjing Forestry University and Tsinghua University have developed a novel, two-step chemical process that converts polystyrene plastic waste directly into high-quality jet fuel. Published in the journal Nature Energy, the breakthrough—based on a single-atom ruthenium catalyst—can produce valuable fuel from polluting waste at low temperatures and pressures, significantly cheaper than previous methods, achieving a yield of 94.8 percent.
Decades-long Challenges of Plastic Recycling
The fundamental problem with recycling plastics through chemical degradation has traditionally been the lack of selectivity. When plastic is simply melted or heated, the result is a disorganized, chaotic mixture of gases, wax, tar, charred residues, and light hydrocarbons. In this process, the fuel fraction that is actually usable in aviation or industry makes up only a negligible part of the total output.
Previous hydrogenolysis processes—which break down the plastic polymer chains using hydrogen—were extremely energy-intensive. These typically required high pressures of around 3 megapascals (MPa) and extremely long reaction times of up to 144 hours in batch reactors. Producing targeted, specific molecules instead of uncontrollable mixtures has been the central technical hurdle for waste-to-fuel technologies for decades.
Innovative Catalyst Design at the Atomic Scale
The research team, led by Professors Yadong Li and Dingsheng Wang, approached the problem from the perspective of catalyst design. Their main question was whether the atomic-level structure of the catalytic active site could provide precise control over product distribution. The solution was individual ruthenium (Ru) atoms deposited on a cobalt-aluminum oxide support. The research proved that the atomic-scale design of single-atom ruthenium catalysts is critical: it pinpoint-controls which bonds break while successfully suppressing the unwanted formation of methane.
Mechanism of the Two-Step Process
The new technology is implemented in two consecutive steps in a tandem fixed-bed reactor. The reactor operates continuously, which represents a massive practical and scalability advantage for future industrial applications compared to previous batch solutions.
The first stage is pyrolysis, during which the polystyrene is heated to 460°C in the presence of hydrogen. At this temperature, the long polymer chains that give polystyrene its solid structure crack into smaller hydrocarbon fragments, primarily styrene monomers and short oligomers. Polystyrene is an excellent starting material because it breaks down relatively cleanly upon heating, emitting consistent intermediate products.
In the second stage, chemical precision takes the spotlight. The vapor-phase fragments from pyrolysis are passed over the ruthenium catalyst at just 160°C, which is drastically lower than the temperature requirements of traditional industrial chemical processes. The isolated ruthenium sites of the catalyst hydrogenate the styrene intermediates into ethylcyclohexane and related cycloalkanes. These are precisely the dense, energy-rich molecules that fit the ideal molecular profile of jet fuels.
Quantitative Results and Economic Viability
The results of the study, expressed in numbers, are also guiding for the sector:
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The process converts polystyrene into targeted cycloalkanes with a 94.8 percent yield, all under low-pressure conditions.
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At atmospheric pressure, the catalyst achieved a turnover frequency of 144/second during benzene hydrogenation, which is more than a hundred times the performance of commercially available ruthenium catalysts.
The economic potential of the method is equally outstanding. Based on the researchers’ preliminary techno-economic analysis, the minimum competitive selling price of the produced fuel is estimated to be between $1.0 and $1.8 per kilogram. This low production cost means that the alternative derived from plastic waste can realistically compete financially with traditional, petroleum-based jet fuels.
References:
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Original research publication (Nature Energy): https://www.nature.com/articles/s41560-026-02078-7