pH对制备直接甲醇燃料电池新型Ir_xS_(1-x)-C阴极催化剂的影响

Influence of pH on Preparation of Novel Ir_xS_(1-x)-C Cathodic Catalysts in Direct Methanol Fuel Cell

以柠檬酸钠为稳定剂,采用氯铱酸、亚硫酸钠、硼氢化钠等为反应物,利用浸渍还原法制备IrxS1-x-C(x=0.7)催化剂;采用粉末X射线衍射、透射电子显微镜、旋转圆盘电极、循环伏安法等测试手段,对比样品在不同pH条件下所制备催化剂的性能。结果表明,当pH=5时,IrxS1-x-C催化剂物相不稳定,并且有杂相生成;当pH=11时,制得的IrxS1-x-C催化剂颗粒的粒度较小,分散性良好,且电化学性能相对优越。

Novel methanol tolerant oxygen reduction catalysts,IrxS1-x-C（x=0.7） used in direct methanol fuel cell,were synthesized via a precipitation method by using H2IrCl6 and Na2SO3 as the precursors,and sodium citrate as the stabilizer,respectively.Powder X ray diffraction and transmission electron microscopy were applied to characterize the phase and morphology of IrxS1-x-C cathodic catalysts respectively.The cyclic voltammetry and rotating disk electrode methods were used for the characterization of the catalyst electroactivity and the catalyzed oxygen reduction reaction kinetics.The performances of different samples prepared in the solution at different pH values were compared.The results show that when pH is 5,IrxS1-x-C phase is instable and the impurity phases generates.When pH is 11,IrxS1-x-C catalysts present the smallest particle size,a well dispersion,and the relatively superior electrochemical properties,comparing to other samples made at pH being 7,9 and 13.