TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Components: The semiconductor quantum dot is cadmium sulfide, lead sulfide or zinc sulfide. Preferred Method: The hydrothermal reaction is preferably carried out for 24 hours at 130-150 degrees C in the step (i). The preparation further comprises: (a) weighing titania P25 (0.5 g) and mixing with 30 ml of sodium hydroxide aqueous solution (10 mol/l), performing ultrasonic treatment for 10 minutes at room temperature, transferring into a high pressure hydrothermal kettle, sealing and performing a hydrothermal reaction for 24 hours at 110-150 degrees C, naturally cooling to room temperature, filtering, washing the powder to be neutral by using deionized water and hydrochloric acid solution (0.1 mol/l), drying the powder obtained by filtering again for 10 hours at 90 degrees C to obtain a titania nanotube white powder with a quasi-anatase phase; (b) mixing 0.25 g of titania nanotube white powder obtained in step (a) with 25 ml of cetyl trimethyl ammonium bromide (CTAB) aqueous solution, filtering, washing and drying to obtain a titania nanotube with the outer wall wrapped by CTAB; (c) adding the titania nanotube with outer wall wrapped by CTAB obtained in step (b) into the tetrahydrofuran solution of a coupling agent (0.2-1 mol/l), then adding 0.05 g of N,N'-dicyclohexylcarbodiimide and stirring for 20 minutes to 12 hours at room temperature, filtering, washing the obtained precipitate by tetrahydrofuran and methanol, then placing the precipitate at 50 degrees C in a drying box to dry for 10 hours to obtain a titania nanotube dry powder with sulfhydryl inner wall; (d) weighing 0.1 g of titania nanotube dry powder obtained in step (c) and adding into 25 ml of nitrate, chloride or acetate aqueous solution of palladium, cadmium or zinc (0.2-1.0 mol/l), mixing, stirring for 15-25 minutes at room temperature, filtering, washing, then placing the precipitate at 50 degrees C in a drying box to dry for 10 hours to obtain a powder; and (e) soaking the powder obtained in step (iii) in 25 ml of sodium sulfide solution (0.1-0.8 mol/l), placing the powder on a magnetic stirrer, stirring for 15-25 minutes at room temperature, filtering, washing, then placing the precipitate at 50 degrees C in a drying box to dry for 10 hours to obtain a final semiconductor quantum dot/titania nanotube catalyst material formed by attaching layer-by-layer assembled semiconductor quantum dots on the inner wall of the titania nanotube.