Turning plastic waste into hydrogen

Researchers have found a way to harvest hydrogen and retrieve valuable graphene from plastic pollution

Spotted: Eradicating plastic pollution and producing hydrogen in a low-carbon process have been the focus of countless researchers and innovators in recent decades. However, the current solutions face challenges when it comes to economic viability and scale-up. While we know how to recycle plastics, the problem lies in current processes being expensive, with high costs associated with the manual separation of plastic types, washing of the waste, and then re-melting of the polymers.

At the same time, though we know how to make hydrogen fuel without producing significant carbon emissions – so-called ‘green hydrogen’ – it is generally much easier and less expensive to use a fossil-fuel-powered process. Now, researchers from Rice University believe they have found a way to harvest hydrogen from plastic waste without generating large volumes of harmful emissions. 

The lab has been working with flash Joule heating, the heat produced when electric current flows through a resistor to achieve ultrafast heating of plastics. The team realised that rapid heating could vaporise the hydrogen in plastics, leaving behind graphene – a pure carbon, super-valuable nanomaterial with applications in strengthening cars, cement, or even in the production of flexible electronics and touchscreens. Even if the graphene created in this process was sold at five per cent of its current market value, the team claims that would completely cover the costs and allow them to produce valuable clean hydrogen for free.   

Using flash Joule heating upcycles the waste plastics with high efficiency using no catalyst or other solvents. At the same time, the team was able to recover up to 68 per cent of the vaporised atomic hydrogen as gas with a 94 per cent purity. Especially because the process creates graphene as a valuable by-product that can be sold, the team highlights that the technique is significantly more affordable – and therefore scalable – than current green hydrogen production methods.

Hydrogen is seen as a promising alternative to fossil fuels. In the archive, Springwise has spotted many ways of sustainably producing the gas, like extracting hydrogen found naturally in the Earth or even from thin air.

Written By: Anam Alam