Preparing method of hexagonal boron nitride with high specific surface area

The invention discloses a preparing method of hexagonal boron nitride with a high specific surface area. According to the method, boric acid and urea are evenly mixed according to the molar ratio of 1 : 45-48 and then are dissolved in water, and under the condition of 55-65 DEG C, thick liquid is formed by magnetic stirring; then the thick liquid is placed in a vacuum drying oven, and white crystal mixtures are obtained; finally, the obtained white crystal mixtures are subjected to high-temperature heat preservation; and the hexagonal boron nitride with the high specific surface area is obtained. The hexagonal boron nitride prepared with the method has the advantages of being high in purity and high in specific surface area and can be used in the fields of gas storing, catalyst carriers and organic pollutant adsorbing. The specific surface area of materials is improved, and the gas storage volume, the catalytic efficiency and the organic pollutant degradation rate can be obviously improved.