▎ 摘　　要

NOVELTY - Catalyst system comprises nickel-phosphomolybdic acid-oxidized epigallocatechin gallate-graphene structure comprising 9-34 wt.% nickel, 5-16 wt.% phosphomolybdic acid, 4-15 wt.% oxidized epigallocatechin gallate and 35-82 wt.% graphene, preferably comprises 17-26 wt.% nickel, 8-13 wt.% phosphomolybdic acid, 7-11 wt.% oxidized epigallocatechin gallate and 50-68 wt.% graphene based on 100% of the total mass of the catalyst system. USE - The catalyst system is useful for preparing L-menthol, comprises nickel-phosphomolybdic acid-oxidized epigallocatechin gallate-graphene structure (claimed). ADVANTAGE - The catalyst system: provides synergistic effect; enables the reaction to be carried out efficiently and rapidly under mild conditions with high reaction conversion rate and chemical selection; and has highest performance of more than 99.5% and long service life. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are also included for: (1) preparing catalyst system, comprising (i) preparing graphene oxide, (ii) preparing phosphomolybdic acid-graphene oxide, and (iii) preparing nickel-phosphomolybdic acid-oxidized epigallocatechin gallate-graphene; and (2) preparing L-menthol, comprising hydrogenating L-menthone using catalyst nickel-phosphoromolybdic acid-oxidized epigallocatechin gallate-graphene prepared as mentioned above.