Plastic Waste Becomes Clean Hydrogen Goldmine
- A technique called flash joule heating at Rice University can convert plastic waste, even unsorted and unwashed, into clean hydrogen and valuable graphene.
- If sold at just 5% of its market value, the graphene produced could make the hydrogen essentially free, provided the process is powered by renewable energies.
- While green hydrogen offers significant potential for decarbonization, especially in high-heat industrial applications, its production requires vast amounts of clean energy, necessitating a balanced approach to its adoption.A study focused on turning waste plastics into high-value graphene just unlocked a new way of producing hydrogen that could transform the nascent industry and, on a grander scale, positively alter projected decarbonization pathways. The breakthrough could be a win-win for the environment, recycling plastic waste – of which the world has approximately 6.3 billion tons – while providing high-yield hydrogen gas which can be used as clean fuel, all while producing graphene as an end product which makes the whole process economically viable. The breakthrough is detailed in a new paper in Advanced Materials.
Until now, the relatively pricey process of creating green hydrogen (as compared to combustible fossil fuels) has been a major barrier for bringing the industry up to a commercial scale. While plenty of hydrogen is already being produced and used in industrial applications, all but a slim fraction of this is gray hydrogen, or hydrogen produced from fossil fuels including coal and gas. Green hydrogen is produced from clean energies, and represents just a sliver of the current hydrogen market.
But if green hydrogen is being produced as a by-product of graphene production, the clean fuel pays for itself – and still yields a considerable profit. “We converted waste plastics—including mixed waste plastics that don’t have to be sorted by type or washed—into high-yield hydrogen gas and high-value graphene,” Kevin Wyss, who led the groundbreaking research at Rice, said in a press release. “If the produced graphene is sold at only 5 percent of current market value—a 95 percent off sale—clean hydrogen could be produced for free.” Of course, the process would still need to be powered with renewable energies for the hydrogen produced to be ‘green.’
The process involves a technique called flash joule heating, developed at Rice. “It involves grinding plastic into confetti-size pieces, mixing it with a conductive material, placing it in a tube, and then passing a very high voltage through it,” Singularity Hub recently reported. “This heats the mixture to around 5,000 degrees Fahrenheit in just 4 seconds, causing the carbon atoms in the plastic to fuse together into graphene and releasing a mix of volatile gases.” Of these gases, there was a significant amount of extremely pure hydrogen. Moreover, since all of the gases’ carbon is converted into graphene, the process does not release any carbon dioxide.