(242a) Recycling Spent Fluid Catalytic Cracking Catalysts As Supports for Sustainable Methane Reforming

The disposal of spent catalysts presents significant environmental and economic challenges due to their metal-containing composition. Recycling these catalysts not only can reduce waste but also it can enable the recovery of valuable metals for various industrial applications. In this study, spent fluid catalytic cracking catalysts (FCCCs) were recycled to produce zeolite-based materials, subsequently doped with nickel for dry reforming of methane (DRM). Comprehensive analyses, including X-ray diffraction (XRD), BET surface area, scanning and transmission electron microscopy (SEM and TEM), H₂-temperature programmed reduction (H₂-TPR), NH₃-temperature programmed desorption (NH₃-TPD), and Ni dispersion via H₂-pulse chemisorption, were used to characterize these catalysts. XRD patterns showed distinct zeolite phases, with Ni doping introducing additional NiO peaks. SEM images displayed diverse morphologies, and TEM-EDX analysis demonstrated uniform nickel dispersion. Nitrogen isotherms indicated mesoporous characteristics, while H₂-TPR elucidated reduction behavior, showing varying nickel-support interactions. Hydrogen consumption and nickel dispersion provided insights into catalytic activity and Ni loading discrepancies. NH₃-TPD profiles highlighted acidity differences, potentially influenced by impurities. Performance evaluation against commercial zeolites revealed that acid-leached recycled zeolites exhibited the highest CO₂ and CH₄ conversion rates and stability, attributed to sodium presence, while the commercial zeolites presented a higher initial methane conversion. Notably, acid-leached zeolites displayed minimal decrease in CO₂ conversion, indicating its potential for prolonged catalytic activity. After 20-hour DRM experiments, TGA and TEM analyses assessed coke deposition, showing majority of the weight loss at 450-550 ℃, with acid-leached zeolites exhibiting minimal deactivation and coke formation. TEM on spent catalysts confirmed the formation of amorphous carbon and carbon filaments, contributing to catalyst deactivation, together with manifesting a sintering effect on nickel nanoparticles, with particle sizes growing up to 130 nm. These findings underscore the potential of recycling strategies in catalyst production and highlight recycled zeolite materials' efficacy in industrial catalytic applications, particularly in DRM reactions.