▎ 摘　　要

NOVELTY - Catalyst, useful for preparing levulinic acid or its esters from biomass, comprising functional groups consisting of phosphoric acid, sulfonic acid and carboxylic acid supported on graphene oxide support element, is new. USE - The catalyst is useful for preparing levulinic acid or its esters from biomass derived from 5 or 6 carbon atoms of carbohydrates, where the biomass contains cellulose or hemicellulose (all claimed). ADVANTAGE - The catalyst exhibits high selectivity and conversion ratio. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for preparing levulinic acid or its esters from biomass comprising preparing glucose from cellulose or hemicellulose, and producing levulinic acid from glucose.