Selective ring opening of phenanthrene over NiW-supported mesoporous HY zeolite catalyst depending on their mesoporosity

•Mesoporous HY zeolites were prepared by pseudomorphic synthesis using TMAOH and CTAB.•The mesoporosity of the zeolites increased with the TMAOH concentration.•Phenanthrene was selected as a model compound for multi-ring aromatics in heavy oil.•NiW/mesoporous HY catalysts were used for selective ring opening of phenanthrene.•The proper mesoporosity enhanced the catalytic performance due to ease accessibility.