Bimetallic FeNi-ZSM-5-catalyzed pyrolysis of photovoltaic waste: Selective and high-yield aromatic valorization for circular resource recovery.

Catalytic pyrolysis, an efficient thermochemical process, offers a promising pathway to valorize thermoset photovoltaic backsheets (TPV) into high-value chemicals. This study investigates the ex situ catalytic pyrolysis of TPV using two acidic catalysts, ZSM-5 and FeNi-ZSM-5, under varied operational conditions, with a focus on product distribution and process efficiency. The catalytic intervention significantly enhanced pyrolysis performance. Both catalysts enhanced pyrolysis oil deoxygenation, reducing acidic compounds and increasing hydrocarbon yields. Temperature elevation further intensified this trend: hydrocarbon content surged from 4.60% to 96.29%, while acidic compounds decreased sharply from 94.64% to trace levels. This shift transformed primary products from benzoic acid derivatives to high-value polycyclic aromatic hydrocarbons. High temperatures (≥ 600 °C) reduced hazardous compounds during fast pyrolysis. During slow pyrolysis, FeNi-ZSM-5 achieved 68.30% benzene selectivity at 485 °C, enriching aromatic content in the gas phase. Joint optimization of five predictive models identified 603 °C with TPV+FeNi-ZSM-5 as optimal or minimal residual mass. These results underscore the dual role of the catalysts in improving conversion efficiency and refining product selectivity. By enabling tailored control over pyrolysis pathways, ZSM-5 and FeNi-ZSM-5 present a scalable strategy for transforming PV waste into value-added chemicals, aligning with circular economy objectives while mitigating environmental hazards.