关键词: 铂纳米晶, 草酰胺, 直接甲醇燃料电池, 电催化

Abstract: Platinum nanocrystallites were synthesized by the colloidal method using oxamide as the stabilizer. The morphologies and electrocatalytic performances for methanol of platinum nanocrystallites prepared at different pH values and with different reactant ratios of precursor and stabilizer were investigated. It was found that the platinum nanocrystallites synthesized at pH=5 and with the reactant ratio of 1:20 showed the best electrocatalytic activity for methanol. The peak current density reached up to 1709 μA·cm^-2. Furthermore, the electrocatalytic activity of platinum nanocrystallites for methanol reduced significantly although the cyclic voltammograms in the blank solution were not obviously changed after exposing in air for 3 months. However, the curves changed significantly after sweeping for 100 cycles in the potential region of 0.05 ~ 1.2 V, indicating that the atomic arrangement of crystal surface had been changed. The easily poisoned (100) surface was gradually transformed to the more active (110) surface, resulting in the increase of electrocatalytic activity for methanol.

Key words: platinum nanocrystals, oxamide, direct methanol fuel cell, electrocatalysis