纳米四氧化三钴催化剂的制备及其电催化性能

Preparation and Electrocatalytic Performance of Nanometer Cobalt Tetroxide Catalysts

四氧化三钴(Co_(3)O_(4))作为一种重要的电极催化材料,具有催化活性高,稳定性好且价格低廉等特点,有望解决过度依赖储量少、成本高的Pt系贵金属催化剂等问题。实验采用化学沉淀法结合热分解法制备出块状、球状及杆状的Co_(3)O_(4),其中球状的最小粒径达8.54nm。将制备的均相高纯度的Co_(3)O_(4)作为直接甲醇燃料电池阴极催化剂来测试电催化活性,结果显示Co_(3)O_(4)具有良好的电催化性能,在1mol/L KOH中氧还原峰电位1.34V,比商用Pt/C(20(wt)%)的高0.05V。在氧气饱和的1mol/L KOH电介质溶液中加入2%无水甲醇,250s后两种材料的电流密度衰减为0.0051和0.0136 mA/cm^(2),半波电位分别为1.025和1.113 V,虽然Co_(3)O_(4)的催化活性不及Pt/C(20(wt)%)材料,但对甲醇的耐受性及稳定性要优于商用Pt/C(20(wt)%)材料。

As an important electrode catalytic material,cobalt tetroxide(Co_(3)O_(4))has the characteristics of high catalytic activity,good stability and low price,which can be expected to solve the problems of over-dependence on the precious metal catalysts of Pt series with low reserves and high cost.In the experiments,the chemical precipitation method combined with thermal decomposition method were used to prepare bulk,spherical and rod-shaped nano Co_(3)O_(4),and the minimum particle size of the spherical was 8.54 nm.Then the homogeneous and high-purity Co_(3)O_(4)was prepared as the cathode catalyst of direct methanol fuel cell to test the electrocatalytic activity.The results showed that Co_(3)O_(4)had good electrocatalytic performance.The ORR peak potential of 1mol/L KOH was 1.34 V,which was 0.05 V higher than that of commercial Pt/C(20(wt)%).After adding 2%of anhydric methanol to the oxygen-saturated 1 mol/L KOH dielectric solution,the current density of the two materials decayed to 0.0051 mA/cm^(2)and 0.0136 mA/cm^(2)after 250 s,and the half-wave potential was 1.025 V and 1.113 V,respectively.Although the catalytic activity of Co_(3)O_(4)was not as good as that of Pt/C(20(wt)%)material,the tolerance and stability of Co_(3)O_(4)to methanol were better than that of commercial Pt/C(20(wt)%)material.