From Plastic Waste to Green Hydrogen and Valuable Chemicals Using Sunlight and Water

• Published in: Angewandte Chemie International Edition 2024-08, Vol.63 (32), p.e202401746-n/a
• Main Authors: Anh Nguyen, Thi Kim, Trần‐Phú, Thành, Daiyan, Rahman, Minh Chau Ta, Xuan, Amal, Rose, Tricoli, Antonio
• Format: Article
• Language: English
• Subjects: Clean energy; Decomposition reactions; Design standards; Green hydrogen; Hydrogen; Hydrogen evolution reactions; Landfills; Oceans; Performance assessment; Performance evaluation; photocatalysis; Photocatalysts; photoreforming; Plastic debris; plastic waste recycle; Solar energy; value-added products; Waste disposal sites
• ISSN: 1433-7851; 1521-3773; 1521-3773
• DOI: 10.1002/anie.202401746

Over 79 % of 6.3 billion tonnes of plastics produced from 1950 to 2015 have been disposed in landfills or found their way to the oceans, where they will reside for up to hundreds of years before being decomposed bringing upon significant dangers to our health and ecosystems. Plastic photoreforming offers an appealing alternative by using solar energy and water to transform plastic waste into value‐added chemical commodities, while simultaneously producing green hydrogen via the hydrogen evolution reaction. This review aims to provide an overview of the underlying principles of emerging plastic photoreforming technologies, highlight the challenges associated with experimental protocols and performance assessments, discuss recent global breakthroughs on the photoreforming of plastics, and propose perspectives for future research. A critical assessment of current plastic photoreforming studies shows a lack of standardised conditions, hindering comparison amongst photocatalyst performance. Guidelines to establish a more accurate evaluation of materials and systems are proposed, with the aim to facilitate the translation of promising fundamental discovery in photocatalysts design. The experimental procedure generally involves two distinct processes: (1) pre‐treatment of original plastics; and (2) photoreforming of these treated molecules. The initial stage is essential for the breakdown of long carbon chains into smaller components via pulverization and monomerization, while the subsequent stage focuses on transforming these components into economically valuable products through photoreforming. Plastic photoreforming employs a photocatalyst, typically a semiconductor, that absorbs sunlight and initiating chemical reactions. This approach has the capacity to convert plastic waste into high‐value chemicals and generate hydrogen (H2) through water splitting under ambient conditions.