Photothermal Synergistic Catalytic Degradation of Epoxy Resin in Waste Wind Turbine Blades over a Vanadium-Based Catalyst

Abstract The efficient recycling of retired wind turbine blades, particularly the degradation of the highly cross-linked epoxy resin (EP) matrix, is a critical challenge for the sustainable development of the wind power industry. This study presents a novel photothermal catalytic oxidation system designed for the high-value recovery of EP using a V2O5 catalyst and O2 under xenon lamp irradiation. To overcome the interfacial mass transfer limitations inherent in heterogeneous catalysis, a solvent strategy is employed to swell and rupture EP, thereby facilitating catalyst penetration. Under xenon lamp irradiation, V2O5 exhibits outstanding photothermal conversion performance, contributing to enhanced degradation efficiency of EP. At a reaction time of 12 h, the degradation ratio of EP reaches 99% under photothermal catalysis, compared with only 74% under electric heating at the same temperature. Moreover, photothermal catalysis enables milder and more uniform cleavage of EP chains, yielding degraded products (DEP) with relatively lower molecular weight (Mw = 6384 g/mol) and narrower distribution (PDI = 1.730). The degradation mechanism begins with the oxidation of C–OH groups to C=O, which subsequently weakens the adjacent C–O–C bond energy and enables its selective cleavage. The resulting DEP are rich in functional groups, endowing them with potential for further conversion into high-value-added materials. Photoelectrochemical characterization confirms the efficient photogenerated carrier separation of V2O5, as evidenced by its small charge-transfer resistance and enhanced photocurrent response. Additionally, its wide bandgap (2.55 eV) and a positive valence band position contribute to stronger oxidation ability, revealing the intrinsic mechanism for the superior performance of V2O5 in EP degradation. The catalyst can be easily recovered from the reaction system and maintains good reusability, highlighting its notable environmental and economic benefits.