▎ 摘　　要

NOVELTY - A ferric oxide nanosheet preparing method involves preparing an aqueous graphene oxide solution, preparing an aqueous solution of ferric nitrate, adding the aqueous solution of ferric nitrate to the aqueous graphene oxide solution, ultrasonically dispersing and mixing sufficiently to obtain a mixed solution. The mixed solution is allowed to stand at room temperature for 12 hours, centrifuged, washed with water, and dried to obtain a graphene oxide/iron nitrate composite material, followed by placing the composite material in a muffle furnace and calcining at 500-600 degrees C for 2-3 hours to obtain the finished product. USE - Method for preparing ferric oxide nanosheet for detecting hydrogen peroxide concentration (claimed). ADVANTAGE - The method enables preparing ferric oxide nanosheet is simple, easy and cost effective manner. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is also included for a method for detecting hydrogen peroxide concentration, which involves dispersing ferric oxide nanosheet into water to obtain a dispersion of ferric oxide nanosheets having a concentration 1-10 mg/ml, adding the 10-100 mu l dispersed ferric oxide nanosheet to 500-900 mu l sodium acetate-acetic acid buffer solution having a pH 3.5--4.5, adding 100-300 mu l a 3,3',5,5'-tetramethylbenzidine ethanol solution having a concentration of 1-5 mM as a colorimetric reaction substrate, adding 3.25-65 mu l 0.01 M aqueous hydrogen peroxide solution, culturing at 35-45 degrees C for 15-60 minutes to obtain a hydrogen peroxide solution having concentration 1-20 mu M, determining the absorbance value of solution of the known hydrogen peroxide concentration in UV region and establishing a standard curve of the concentration-absorbance photometric value, followed by calculating the concentration of hydrogen peroxide in the solution by measuring the absorbance value of the unknown hydrogen peroxide concentration solution.