Scientists Develop Single-Atom Iron Catalyst for Simultaneous Plastic Degradation and Green Hydrogen Production

Under neutral pH conditions, the catalyst demonstrates outstanding catalytic activity and stability, surpassing previous methods for microplastic treatment. It is applicable for addressing microplastic pollution in various water bodies, including rivers, lakes, and oceans, and can effectively process nearly all common types of plastics.

Microplastics: An Ubiquitous Environmental Threat

Plastics are widely used in daily life due to their excellent durability, low cost, and multifunctionality. However, their excessive use has led to serious environmental challenges. Since the 1950s, over 8.3 billion tons of plastic have been produced globally, with 80% becoming waste that ultimately enters the natural environment. Improper management of plastics has resulted in their accumulation in soil, water bodies, and air, breaking down into microplastic particles and becoming one of the most persistent and widespread environmental threats facing humanity.

Microplastics not only originate from the degradation of discarded plastics but are also continuously released through everyday activities, such as from polystyrene foam food containers under high temperatures or aging plastic pipes. These microplastics are virtually everywhere. Although they are invisible to the naked eye, their potential harm to ecosystems and human health cannot be ignored.

The Research Process Behind Innovative Catalysts

To effectively combat microplastic pollution, the research team at the University of Adelaide embarked on a quest to find efficient catalysts. They designed and synthesized various catalysts, ultimately discovering that iron-based catalysts performed best in microplastic degradation. Advanced analytical techniques were employed to verify the structure and performance of the catalyst.

During performance testing, the researchers systematically evaluated the catalyst's effectiveness in degrading microplastics and optimized reaction conditions to enhance degradation efficiency. Mechanistic studies using gas chromatography-mass spectrometry revealed that the degraded plastics primarily converted into C3-C20 organic compounds, especially short-chain organic acids, which can serve as feedstock for photocatalytic hydrogen production, thereby achieving resource reuse.

The Unique Advantages of Single-Atom Iron Catalysts

This single-atom iron catalyst features a unique structure and high catalytic activity, enabling it to degrade difficult-to-process plastics like ultrahigh molecular weight polyethylene under relatively mild conditions. Experimental results indicate that the catalyst retains high activity after multiple cycles of use, demonstrating excellent durability and industrial application potential.

The research team also tested the degradation effects on various common plastics, finding that the catalyst exhibited superior degradation capabilities across different plastic types. Through in-depth analysis of the intermediate products generated during the degradation process, the researchers discovered that the primary degradation products are short-chain organic acids, which can be further utilized, promoting waste reuse goals.

Experimental Results and Application Prospects

The catalyst effectively degrades difficult-to-process plastics such as ultrahigh molecular weight polyethylene under relatively mild conditions, maintaining its activity and stability even after repeated use. This suggests that the catalyst has excellent durability for practical applications and potential for industrial-scale implementation.

The research indicates that the catalyst's strong performance across various plastic types demonstrates its versatility and adaptability. Additionally, the team conducted ecological toxicity assessments on the intermediate products produced during degradation to ensure the environmental friendliness of the process.

Future Outlook

The related research findings have been published in Nature Communications. Moving forward, the team at the University of Adelaide plans to further optimize the catalyst's structure to improve degradation efficiency and scale up experiments to verify its feasibility in practical applications. This innovative catalytic technology provides an economically viable solution to plastic pollution while potentially advancing the hydrogen economy. Through this research, scientists have opened new avenues for sustainable clean energy production.

However, addressing microplastic pollution still faces many challenges, including considerations of cost, efficiency, and stability in real-world applications. In-depth ecological toxicity assessments should also be conducted to ensure the environmental safety of the degradation process. Globally, tackling microplastic pollution requires collaborative efforts from governments, research institutions, and businesses.

References

1.Wenjie Tian, Pingan Song, Huayang Zhang, Xiaoguang Duan, Yen Wei, Hao Wang, & Shaobin Wang, *Microplastic materials in the environment: Problem and strategical solutions*, Progress in Materials Science, 132, 2023, 101035. [https://doi.org/10.1016/j.pmatsci.2022.101035](https://doi.org/10.1016/j.pmatsci.2022.101035)

2. Jingkai Lin, Kunsheng Hu, Yantao Wang, Wenjie Tian, Tony Hall, Xiaoguang Duan, Hongqi Sun, Huayang Zhang, Emiliano Cortés & Shaobin Wang, *Tandem microplastic degradation and hydrogen production by hierarchical carbon nitride-supported single-atom iron catalysts*, Nature Communications 15, 2024, 8769. [https://doi.org/10.1038/s41467-024-53055-1](https://doi.org/10.1038/s41467-024-53055-1)