Method for preparing size controllable nano stannic oxide

A method for preparing size controllable nano stannic oxide comprises the following steps: weighing tetrachlorostannane pentahydrate to be dissolved in alcohol, preparing stannic chloride alcohol solution of which the molarity is 0.50 to 2.00 mol/L, adding alcohol and distilled water to dilute, adjusting the molarity of stannic chloride as 0.025 to 0.125 mol/L, enabling the volume ratio of alcohol and water in the solution to be 1:1, adjusting the pH value of ammonia water to be 10 to 12, generating a white sediment, and generating a suspending liquid, namely a precursor suspending liquid; moving the precursor suspending liquid into a high pressure reaction kettle which takes polytetrafluoroethylene as inner liner at the temperature of 110 to 190 DEG C, reacting for 12 to 36 hours, cooling to the room temperature, centrifugally separating the product, washing and drying the product, and obtaining the nano stannic oxide. The preparation method is safe and environment-friendly, low in raw material cost, easy to obtain, simple in preparation technology, short in period, and easy to operate and realize industrialized volume production. The prepared nano stannic oxide is rutile stannic oxide, is high in crystallinity, uniform in grain, small in particle size which can be controlled in a range of 2 to 7 nm and good in gas-sensitivity, can be used for producing highly sensitive gas sensitive element, and has a sound application prospect.