Effect of Calcination Temperature of FeCoOx/Al2O3 Catalyst on the Catalytic Pyrolysis of High-Density Polyethylene

Catalytic pyrolysis has emerged as a promising approach for converting waste plastics into high-value-added chemicals and fuels. This study aims to investigate the effect of calcination temperature on the catalytic performance of FeCoOx/Al2O3 catalysts for high-density polyethylene (HDPE) pyrolysis and to optimize the catalyst preparation conditions for maximizing valuable product yields. FeCoOx/Al2O3 catalysts were synthesized via a hydrothermal method and calcined at various temperatures (300–700 °C). The results demonstrate that calcination temperature significantly influences product distribution: gas yield increased with rising calcination temperature, whereas carbon yield, hydrogen yield, and hydrogen content decreased accordingly. Among all tested temperatures, the catalyst calcined at 500 °C achieved the optimal performance, yielding solid carbon at 23.0 wt. % with a hydrogen content of 80 vol.%. This superior performance can be attributed to its larger specific surface area, a richer pore structure, and better reducibility compared to those calcined at higher temperatures, which also facilitated the formation of solid carbon with the highest degree of graphitization and purity. This work provides technical guidance for the high-value utilization of waste plastics through catalytic pyrolysis.