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Hydrogen generation from plastic waste

US researchers have developed a new method for generating hydrogen from plastic waste, Euwid reports.


Researchers at Rice University (Houston, Texas) have developed what they say is an emission-free method for extracting hydrogen from plastic waste that could prove profitable. "In this work, we converted plastic waste ⎯ including mixed waste that does not need to be sorted or washed by type ⎯ into high-yield hydrogen gas and high-quality graphene," explains Kevin Wyss (pictured left), a former Rice doctoral student and lead author of a related study in the journal Advanced Materials. To do this, the researchers exposed samples of plastic waste to a rapid Joule flash heating for about four seconds, which led to a temperature increase to 3,100 degrees Kelvin or the equivalent of about 2,800 degrees Celsius and to an evaporation of the hydrogen contained in the plastics. What remains, according to the study, is graphene ⎯ an extremely light and resistant material consisting of a single layer of carbon atoms. If the graphene produced in the process were sold at just five per cent of its current market value, it could be used to produce clean hydrogen in a cost-neutral way, says Wyss. "Green" hydrogen from renewable sources costs just under six euros per kilogram, according to the International Renewable Energy Agency (Irena). Of the nearly 100 million tonnes of hydrogen consumed worldwide in 2022, most is produced from fossil fuels, which involves emissions of about 12 tonnes of carbon dioxide per tonne, according to Rice University. James Tour, professor of chemistry, materials science and nanoengineering at Rice University, says: "The demand for hydrogen is likely to skyrocket in the next few decades, so we won't be able to produce it in the same way we have in the past if we are serious about achieving net-zero emissions by 2050." Wyss hopes that the method his team has developed will enable the production of clean hydrogen from plastic waste, potentially solving major environmental problems such as plastic pollution and the greenhouse gas-intensive production of hydrogen through steam methane reforming. According to Wyss, the techniques developed in the project, particularly life cycle assessment and gas chromatography, could also be applied to other Rice research group projects.

  • (Sept. 19, 2023)
  • Photo: Rice University, Gustavo Raskosky

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