以草酰胺作为保护剂，采用胶体法合成铂纳米晶，考察了不同溶液pH值、前驱体与保护剂反应物配比对铂纳米晶形貌及其甲醇电催化氧化活性的影响. 测试表明，pH = 5、反应物配比1:20合成的铂纳米晶的甲醇电催化氧化活性最佳，其峰电流密度达到1709 μA·cm^-2. 空气中搁置3个月后，其表面形貌变化不大，但甲醇的电催化活性显著降低. 0.05 ~ 1.2 V电位范围循环扫描100周期，其循环伏安曲线明显变化，晶体表面原子排列方式也发生变化，由易毒化(100)面逐渐转化为(110)面，其甲醇电催化活性增加.

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.