Recovery of spent alumina-supported platinum catalyst and reduction of platinum oxide via plasma sintering technique

A thermal plasma process for the recovery of the spent alumina-supported platinum catalyst (Pt/Al2O3) and reduction of platinum oxide (PtO2) was developed. The spent Pt/Al2O3 and PtO2 catalysts were sintered at >1500 K under plasma condition and were reformed or reduced to metallic platinum, which were proven by XRD and EDX. Results from SEM and BET specific surface area analyses indicated that the organic tar with the intermolecular and intramolecular water on the surface of the spent catalysts was decomposed and converted to syngas (CO, CO2, and H2), which might be the reducing agents in the process. Time-programmed hydrogenation study of urocanic acid was carried out to compare the catalytic efficacy of recovery and fresh Pt/Al2O3 catalysts. The experimental result indicated that the plasma sintered Pt/Al2O3 catalyst showed the similar catalytic efficacy with respect to the fresh catalyst.