TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Process: In the process (M1): before adding the chelating agent into the solvent, selecting the chelating agent from ethylenediamine, 1,10-phenanthroline, 2,2'-bipyridine, diethylenetriamine, triethylenetetraamine, phenanthroline, or bipyridine. The chloroplatinic acid and the chelating agent are mixed with the solvent by continuously stirring. The solvent is sonicated after the chloroplatinic acid and the chelating agent are added into the solvent. The solvent is sonicated for 4-6 hours. The mole ratio of the chelating agent to Pt is 1:1-3:1 (preferably 1:1-2:1) with the chelating agent being diethylenetriamine. The mole ratio of the chelating agent to Pt is 1:1-1.5:1, with the chelating agent being triethylenetetraamine. The mole ratio of the chelating agent to Pt is 2:1-3:1, with the chelating agent being ethylenediamine, 2,2'-bipyridine, or 1,10-phenanthroline. In the process (M2) and (M3): a step to use formaldehyde as the reductant is performed before adding the reductant into the platinum complex solution. The mole ratio of formaldehyde to the chloroplatinic acid is 20:1. During the reduction step, after adding the reductant into the platinum complex solution to form the suspension, an alkaline solution is gradually added into the suspension until pH of the suspension is more than 7 (preferably 12-14). In method (M2) and (M3), a step to use sodium hydroxide as the alkaline solution is performed before adding the alkaline solution into the suspension. After adjusting pH of the suspension, the suspension is further sonicated. The suspension is sonicated for 0.2-5 hours. During the reduction step, after adding the reductant into the platinum complex solution to form the suspension, the suspension is heated up prior to the drying step. The suspension is heated by a microwave process. After heating the suspension, the suspension is cooled prior to the drying step. After completing the reduction step, a separation step is further executed to separate Pt-nanoparticles from the suspension prior to the drying step. The mole ratio of the chelating agent to Pt is 1:1-3:1 (preferably 1:1-2:1). The temperature for the drying step is 373-423 degrees K. In the process (M3): the chloroplatinic acid, the chelating agent, and the supports are mixed with the solvent to get a platinum complex solution with the supports, with the supports being porous materials. The chloroplatinic acid, chelating agent and the supports are mixed with the solvent by continuously stirring. The solvent is sonicated after the chloroplatinic acid, the chelating agent, and the supports are added into the solvent. The solvent is sonicated for 4-6 hours. In method (M3), during the reduction step, after adding the reductant into the platinum complex solution with the supports to form the suspension, an alkaline solution is gradually added into the suspension until pH of the suspension is more than 7 (preferably 12-14). In method (M3), during the reduction step, after adding the reductant into the platinum complex solution with the supports to form the suspension, the suspension is heated prior to the drying step. The suspension is heated by microwave. After heating the suspension, it is cooled prior to the drying step. After completing the reduction step, a separation step is further executed to separate Pt nanoparticles from the suspension prior to the drying step at 373-423 degrees K. During the chelating step, the chloroplatinic acid and the chelating agent are added into the solvent either before adding the supports, or after adding the supports, or the supports are mixed with ethanol and then adding the supports into the solvent. EXAMPLE - No suitable example given.