Linear low-density polyethylene gasification over highly active Ni/CeO₂-ZrO₂ catalyst for enhanced hydrogen generation

Steam-gasification of linear low-density polyethylene (LLDPE) waste to hydrogen-rich gas has been studied systematically over nickel (10 wt.%) loaded on a variety of supports (Al₂O₃, CeO₂, and CeO₂-ZrO₂) synthesized using a novel solvent deficient method (SDM). The hydrogen selectivity order of the catalysts was reported as Ni/CeO₂-ZrO₂>Ni/CeO₂>Ni/Al₂O₃. The highest catalytic H₂ selectivity of the Ni/CeO₂-ZrO₂ catalyst was reported to be ∼76 vol.%, and was attributed to the smaller nickel crystals that were finely dispersed on the support, and to formation of Ce_1-xZr_xO_2-δ solid solutions. The Ce_1-xZr_xO₂-_δ solid solution in the Ni/CeO₂-ZrO₂ catalyst was observed to be bi-functional, thus reflecting the acceleration of the water gas shift and the oxidation of carbon to CO and CO₂. The better resistance of the Ni/CeO₂-ZrO₂ catalyst towards coke deposition also indicated its potential for commercial-scale applications for the steam gasification of plastics. Therefore, this research provides an advanced route to recycle LLDPE plastic waste into hydrogen fuel, which presents both economical and environmental benefits.