Influence of nickel-based catalysts on syngas production from carbon dioxide reforming of waste high density polyethylene

Syngas production (H₂ and CO) from carbon dioxide reforming of high density polyethylene (HDPE) over Ni-Al catalyst was evaluated in a two-stage fixed bed reactor. Syngas production was favoured by CO₂ addition, with the highest production of 138.81 mmol_syngas g^-1_HDPE, which was about six times higher than non-catalytic, non-CO₂ addition. The catalytic performances of nickel-based catalysts with different promoter metals (Cu, Mg and Co) in the CO₂ reforming of HDPE were also studied. It was found that Ni-Co-Al had an excellent anti-coking performance, with no detectable formation of coke on the catalyst surface. Moreover, the syngas production was significantly improved by the addition of Co compared to the Cu and Mg metal promoters. The CO₂ conversion for Ni-Co-Al catalyst was also the highest at 57.62%. Further investigation of the effect of Co concentration on CO₂ reforming of HDPE showed that the higher Co content, the higher the syngas production and CO₂ conversion.