Upcycling phenyl-based waste: hypercrosslinking strategies and applications

Phenyl-based wastes (PWs) originating from plastics, coal tar, asphalt, and laboratory byproducts pose serious environmental concerns due to their chemical stability and persistence. Traditional treatments such as landfilling or incineration risk secondary pollution and inefficient carbon utilization. As a sustainable alternative, transforming PWs into porous materials via hypercrosslinking reactions (e.g., Friedel–Crafts alkylation) enables direct conversion of aromatic waste into high-surface-area frameworks with tunable porosity and multifunctionality. Despite growing progress in PW upcycling, comprehensive reviews remain scarce, particularly those systematically evaluating how reaction time and temperature govern porosity evolution, a key factor for optimizing synthesis and performance. This Review bridges that gap by summarizing the chemical characteristics of PWs, recent advances in porosification strategies, and their impact on structure–property–function relationships. The versatile applications of hypercrosslinked phenyl-based wastes (HCPWs) in gas adsorption, carbon capture, catalysis, and environmental remediation are critically examined, along with current limitations and future perspectives. By integrating waste valorization with materials design, this work outlines a promising pathway toward circular carbon utilization and sustainable porous materials innovation. • Hypercrosslinking strategies enable the upcycling of phenyl-based waste into high-value porous materials with tunable structures and functions. • Structure–property relationships are systematically evaluated to guide rational design of sustainable porous materials for gas storage, carbon capture, and catalysis. • Challenges and perspectives are discussed for making HCPW a versatile and large-scale strategy.