Co-CoTiO_(3)/TiO_(2)的制备及其高温质子交换膜燃料电池性能

Preparation of Co-CoTiO/TiO and Performance of High Temperature Proton Exchange Membrane Batteries

高温质子交换膜燃料电池相较于低温质子交换膜燃料电池具有更加简单的水热管理系统,另外,工作温度的提高不仅增强了电化学反应性能,而且提升了催化剂的抗CO中毒性能,是一种极具应用潜力的燃料电池。本工作先通过水热法合成了纳米棒状的TiO_(2),再在合成金属有机框架(ZIF-67)的过程中加入该纳米棒状的TiO_(2),最后在氮气气氛下煅烧,得到一系列不同Co含量的Co-CoTiO_(3)/TiO_(2)催化剂。采用X射线衍射(XRD)和透射电镜(TEM)等表征了催化剂的结构,在0.1 mol/L的KOH电解液中研究了催化剂的氧还原(ORR)性能。结果表明:含15 mmol(1 mmol TiO_(2)所含Co的量)Co的Co-CoTiO_(3)/TiO_(2)催化剂的ORR催化活性最好,半波电势可达0.84 V,起始电位为0.92 V,极限电流密度可达4 mA/cm^(2),接近同样测试条件下的20%Pt/C(其中Pt的质量占总催化剂的20%)的ORR催化活性。在高温质子交换膜燃料电池应用中,在180℃和40 mA/cm^(2)的条件下,最高功率密度为9 mW/cm^(2)。

Compared with the low-temperature proton exchange membrane fuel cell,the high-temperature proton exchange membrane fuel cell has a simpler hydrothermal management system,and the higher operating temperature,which not only enhances the electrochemical reaction performance,but also improves the anti-CO poisoning performance of the catalyst,so it is a kind of fuel cell with great application potential.In this work,nanorod-like TiO_(2)was first synthesized by hydrothermal method,and then the nanorod-like TiO_(2)was added in the process of synthesizing the metal-organic framework(ZIF-67).The resulting precursor was calcined under nitrogen atmosphere,and finally a series of Co-CoTiO_(3)/TiO_(2)catalysts with different Co contents were obtained.The structure of the catalysts was characterized by X-ray diffraction(XRD)and transmission electron microscopy(TEM),and the oxygen reduction(ORR)performance of the catalysts was evaluated in 0.1 mol/L KOH electrolyte.The results showed that the 15 mmol-Co-CoTiO_(3)/TNT-800 has the best ORR activity,with the half were potential of 0.84 V,the initial potential of 0.92 V and the limit current density of 4 mA/cm^(2),which were close to those of 20%Pt/C(in which the mass of Pt accounts for 20%of the total catalyst)under the same test conditions.In high temperature proton exchange membrane fuel cell applications,the highest power density was 9 mW/cm^(2)at 180℃and 40 mA/cm^(2).