How lasers and 2D materials can solve the world’s plastic problem

A global research team led by Texas Engineers has developed a way to irradiate the molecules in plastic and other materials with a laser, breaking them down into tiny particles for future reuse.

The discovery, which involves laying these materials on two-dimensional materials called transition metal dichalcogenides and then igniting them, could improve the way we process plastics that are difficult to degrade with current technologies.

“By harnessing these unique reactions, we can explore new ways to convert environmental pollutants into valuable, reusable chemicals, contributing to the development of a more sustainable and circular economy,” said Yuebing Zheng, a professor in the Cockrell School of Engineering’s Walker Department of Mechanical Engineering and one of the project’s leaders.

“This discovery has important implications for addressing environmental problems and advancing green chemistry.”

The research was recently published in Nature communicationThe team includes researchers from the University of California, Berkeley; Tohoku University in Japan; Lawrence Berkeley National Laboratory; Baylor University; and The Pennsylvania State University.

Plastic pollution has become a global environmental crisis, with millions of tons of plastic waste accumulating in landfills and oceans each year. Conventional methods of plastic degradation are often energy-intensive, environmentally damaging, and ineffective. The researchers anticipate that they can use this new discovery to develop efficient plastic recycling technologies to reduce pollution.

The researchers used low-power light to break the chemical bond of the plastics and create new chemical bonds that turned the materials into luminescent carbon dots. Carbon-based nanomaterials are highly sought after for their many capabilities, and these dots could potentially be used as memory storage devices in next-generation computing devices.

“It’s exciting to turn plastic that might never break down on its own into something that’s useful for many different industries,” said Jingang Li, a postdoctoral student at the University of California, Berkeley, who initiated the research at UT.

The specific reaction is called CH activation, in which carbon-hydrogen bonds in an organic molecule are selectively broken and transformed into a new chemical bond. In this study, the two-dimensional materials catalyzed this reaction, which resulted in hydrogen molecules turning into gas. This cleared the way for carbon molecules to bond with each other to form the information storage dots.

Further research and development are needed to optimize the light-driven CH activation process and scale it up for industrial applications. However, this study represents an important step forward in the search for sustainable solutions for plastic waste management.

The light-driven CH activation process demonstrated in this study can be applied to many long-chain organic compounds including polyethylene and surfactants that are widely used in nanomaterial systems.