▎ 摘　　要

NOVELTY - Complex oxide catalyst, comprises multi-level structure hydrotalcite layered double hydroxides (LDHs) nanometer piece arrays/graphene hybrid material, where: amount of graphene is 8-25% amount of LDHs; size of LDHs nanometer piece is 20-120 nm and thickness is 5 nm, morphology is perpendicular to each other; staggered growth is on both base surface sides of graphene, forming three-dimensional honeycomb like array morphology. The hybrid material is calcined. The template guide action is based on graphene. USE - Used as complex oxide catalyst. ADVANTAGE - The catalyst has improved catalytic activity. The method solves the problem of reunion of LDHs nanosheets. DETAILED DESCRIPTION - Complex oxide catalyst, comprises multi-level structure hydrotalcite layered double hydroxides (LDHs) nanometer piece arrays/graphene hybrid material, where: amount of graphene is 8-25% amount of LDHs; size of LDHs nanometer piece is 20-120 nm and thickness is 5 nm, morphology is perpendicular to each other; staggered growth is on both base surface sides of graphene, forming three-dimensional honeycomb like array morphology. The hybrid material is calcined. The template guide action is based on graphene, enabling LDHs nanometer piece arrays roasting to maintain three-dimensional nanosheet array morphology, where composite oxide nanosheet has 7-12 nm thickness, 8-10 nm small size oxide particles assembly and developed pore structure. An INDEPENDENT CLAIM is also included for preparing complex oxide catalyst, comprising (i) taking 325 mesh natural crystalline flake graphite as raw material, using chemical oxidation preparing graphite oxide, drying using freeze drying method, freezing at -60 degrees C for 1 hour, drying under vacuum for 12 hours to obtain fluffy graphite oxide, dispersing fluffy graphite oxide in deionized water and carrying out ultrasonic dispersion to obtain a uniform graphene oxide colloidal suspension, (ii) dissolving metal salt and citric acid in deionized water to obtain mixed solution A, slowly pouring step (i) uniform graphene oxide colloidal suspension into mixed solution A to obtain slurry, carrying out ultrasonic stirring to obtain brown yellow slurry B, (iii) dissolving sodium hydroxide and sodium carbonate, dissolving in deionized water to obtain mixed alkali solution C, adding mixed alkali solution C and step (ii) brown yellow slurry B into 100 ml deionized water in four-necked flask, controlling pH at 10 plus minus 0.1, crystallizing under cooling water bath to obtain black precipitate, washing with deionized water until pH and freeze drying to obtain multi-level structure hydrotalcite layered double hydroxides (LDHs) nanometer piece arrays/graphene hybrid material, and (iv) roasting moderately to obtain complex oxide catalyst.