【摘要】 对比研究了用三种液相沉积还原法制备的 2 0 %Pt/C催化剂及在 90 0℃下用H2 还原处理的催化剂 ,并用XRD和TEM等技术表征了催化剂的粒子大小及粒径分布 .结果表明 ,用乙二醇还原法制备的Pt/C催化剂的平均粒径最小 (约 2 4nm) ,且分布均匀 .应用旋转圆盘电极 (RDE)法和直接甲醇燃料电池单池评价了Pt/C催化剂的氧还原反应 (ORR)活性 ,探索了单池性能与催化剂粒径大小的关系 .RDE测试结果表明 ,用甲醛还原法制备的Pt/C催化剂具有最高的ORR活性 ;而单池测试结果表明 ,用乙二醇还原法制备的Pt/C催化剂显示出最高的ORR活性和最优的单池性能 .这可能是因为直接甲醇燃料电池中所需Pt/C催化剂最优粒径更小的缘故 .另外 ,研究了Cl-对Pt/C催化剂ORR活性的影响 .结果表明 ,少量Cl-即会显著降低Pt/C催化剂的ORR活性更多还原

【Abstract】 The carbon supported platinum catalysts 20%Pt/C were prepared by reduction of platinum salts with various reducing agents (such as NaBH 4, HCHO and EG(ethylene glycol)) in various solvents (such as H 2O, i PrOH and EG ). The Pt/C(EG) catalyst was treated at 900 ℃ in hydrogen atmosphere. The distribution and size of Pt metal particles in the Pt/C catalysts were characterized by XRD and TEM. The Pt metal particles of Pt/C(EG) catalyst are highly and homogeneously dispersed with a narrow size distribution, centering at 2 4 nm. The rotating disk electrode (RDE) tests showed that the activity order of the catalysts for orygen redutive reaction (ORR) is as follows: Pt/C(HCHO)>Pt/C(EG)>Pt/C(NaBH 4). However, the Pt/C(EG) catalyst exhibits enhanced activity for ORR and superior performance in direct methanol fuel cell test as compared with the Pt/C catalysts prepared by the other two methods and the heat treated Pt/C, which could have smaller Pt particle size. Pt/C(EG) catalyst showed better performance at activation controlled region and comparative power density as compared with the commercial Pt/C catalyst. Cl - shows a negative effect on the ORR in both DMFC and RDE tests.更多还原