Catalyst Design and Engineering for Enhanced Microplastic Degradation and Upcycling—A Review

Microplastics (MPs), defined as synthetic polymer particles ranging from 1 μm to 5 mm, originate from various sources, including synthetic textiles, tire wear, degraded plastic waste, etc. Their small size and chemical stability make them challenging to remove, collect and degrade, posing significant adverse effects to both ecosystems and human health. While efforts to develop sustainable alternatives and removal methods are ongoing, effective solutions remain limited. Catalytic degradation and upcycling present a promising route to mitigate MP pollution by enabling efficient breakdown into less harmful molecules and potential upcycling into valuable products with lower energy requirements. This review provides a comprehensive overview of recent advances in catalyst design and development specifically for MP degradation, highlighting photochemical, thermal, biological, electrochemical, and hybrid approaches. Key challenges, reaction mechanisms, and future directions are discussed, offering a timely reference for researchers in this emerging field.