Photocatalytic Waste Polystyrene Plastic Conversion: Reaction Mechanism and Catalyst Design

The rapid accumulation of plastic waste has caused global environmental pollution and resource scarcity. Converting plastic wastes into valuable chemicals and fuels has emerged as promising strategies to mitigate plastic pollution and promote a circular economy. Especially, photocatalytic conversion of waste polystyrene (PS) plastic has received much attention in recent years. This review summarizes the progress in catalytic conversion of PS into value-added chemicals by photocatalysis. The understanding of reaction pathways, design of efficient catalysts, and practical applicability are highlighted and discussed. Our goal is to elucidate the catalytic mechanisms and principles of catalyst design, providing guidance for the development of efficient photocatalysts to enhance catalytic activity, product selectivity, and processing capabilities for PS plastic waste. We also assessed the economic feasibility based on techno-economic analysis, which will provide valuable insights into the cost-effectiveness and potential industrial applications of the technology. The ongoing challenges and future research directions in this area are critically discussed, offering a roadmap for overcoming barriers and advancing the field toward more sustainable waste management solutions.