The effect of Ru on co-impregnated NiRu-supported hierarchical Beta zeolite (NiRu/h-Beta) and Ru/h-Beta as catalysts in the hydroreforming of the oil obtained by LDPE thermal cracking has been investigated, determining the thermal stability of the metal particles after two reaction-regeneration cycles. The formation of Ni-Ru particles on the fresh catalysts has been evidenced by XRD, H-2-TPR and EDS analyses. Bimetallic Ni-Ru catalysts enhanced the light diesel share. Regeneration treatment by calcination in air and reduction under hydrogen of the spent catalysts largely recovered the original activity of fresh Ni5% + Ru1%/h-Beta while a stabilizing effect of ruthenium on nickel particles against sintering was observed. On the contrary, regeneration treatments on Ru1%/h-Beta clearly modified the feature of the metallic phase forming larger Ru nanoparticles. Thus, the regenerated Ru/h-Beta gave rise to more oligomerization activity in the second reaction cycle, leading to almost 24% of heavy diesel. (c) 2014 Elsevier Ltd. All rights reserved.