The influence of heat treatment on the improvement of the catalytic activity of CoTETA/C catalysts is investigated. These non-precious metal oxygen reduction catalysts are prepared from carbon-supported cobalt triethylenetetramine (CoTETA/C) and heat treated in the temperature interval from 500 to 1000 °C in Ar atmosphere. Electrochemical characteristics are demonstrated in oxygen-saturated acid electrolyte by rotating disk electrode, cyclic voltammetry, as well as single fuel cell tests. The results show that the effect of heat treatment is important on the catalytic activity of CoTETA/C catalysts for the ORR and a maximum catalytic activity is obtained after heat treatment at 800 °C. The ORR reaction mechanism on the catalysts heat treated at 700, 800 and 900 °C is mainly through a 4e reaction path, while a 2e reaction is dominant on the catalysts heat treated at 500, 600 and 1000 °C. Tafel slopes of the CoTETA/C catalysts are all around −200 mV/dec. X-ray absorption measurements reveal that the CoN₄ centers are no longer detected after heat treatment. XRD results clearly confirm the formation of nanometallic α-Co with different sizes aggregated. A possible interpretation of the catalytic active sites is also discussed.

研究了热处理对提高CoTETA / C催化剂催化活性的影响。这些非贵金属的氧还原催化剂由碳负载的三亚乙基四胺钴（CoTETA / C）制备，并在Ar气氛中在500至1000°C的温度区间内进行热处理。通过旋转圆盘电极，循环伏安法以及单燃料电池测试，证明了氧饱和酸电解质中的电化学特性。结果表明，热处理效果对CoTETA / C催化剂对ORR的催化活性很重要，并且在800°C热处理后可获得最大催化活性。在700、800和900°C热处理的催化剂上的ORR反应机理主要是通过4e反应路径进行的，而2e反应则是在500、600和1000°C热处理的催化剂上的主要反应。CoTETA / C催化剂的塔菲尔斜率均在-200 mV / dec附近。X射线吸收测量表明CoN热处理后不再检测到_4个中心。XRD结果清楚地证实了聚集了不同尺寸的纳米金属α-Co的形成。还讨论了催化活性位的可能解释。