TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preparation: Preparation of the catalyst with core-shell structure, comprises: (a) forming a first substance by adding ruthenium trichloride into glycol, and forming a second substance by adding polyvinylpyrrolidone into glycol; (b) forming a third substance by mixing the first substance and the second substance; (c) heating the third substance to a first degree and then passing nitrogen for flowing in the third substance; (d) forming a fourth substance by mixing the third substance, the second substance, chloroplatinic acid, hexahydrate, and glycol; and (e) forming the catalyst with core-shell structure by heating the fourth substance to a second degree and then passing nitrogen for flowing. Preferred Method: The step (a) further comprises forming: the first substance by vibrating ruthenium trichloride and glycol with a first period through an ultrasonic vibrator at room temperature, where the first period is 60 minutes; and the second substance by stirring polyvinylpyrrolidone and glycol with a second period and a first rate at room temperature, where the second period is 30 minutes and the first rate is 500 revolution per minute (rpm). The step (b) further comprises stirring the first substance and the second substance with a third period and a second rate at room temperature, where the third period is 30 minutes and the second rate is 500 rpm. The step (c) further comprises: stirring the third substance with a third rate at the first degree, where the third rate is 120 rpm and the first degree is 140-180 degrees C; passing nitrogen in the third substance for flowing a fourth period in the third substance, where the fourth period is 120 minutes; adding the third substance into acetone and removing acetone after the third substance condensed; and step of adding the third substance into ethanol and waiting the third substance re-dispersed. The step (d) further comprises: forming the fourth substance by stirring chloroplatinic acid, hexahydrate and glycol with a fifth period and a fourth rate at room temperature, where the fifth period is 30 minutes and the fourth rate is 500 rpm; and stirring with a fifth rate and sixth period, where the fifth rate is 500 rpm and the sixth period is 20-30 minutes. In the method, the second degree is 140-180 degrees C, and the volume of acetone is 10 times larger then the third substances. EXAMPLE - None given.