Development of non-platinum catalysts for polymer electrolyte membrane fuel cell cathodes

聚合物电解质膜燃料电池阴极非铂催化剂的开发

基本信息

批准号：
21760154
负责人：
CHISAKA Mitsuharu
金额：
$ 2.83万
依托单位：
Toyohashi University of Technology
依托单位国家：
日本
项目类别：
Grant-in-Aid for Young Scientists (B)
财政年份：
2009
资助国家：
日本
起止时间：
2009 至 2010
项目状态：
已结题

项目摘要

Highly stable carbon-supported hafnium oxynitride (HfO_xN_y-C) was synthesized by heating carbon-supported hafnium oxide, prepared using an impregnation method, under NH3 gas in various conditions. X-ray diffraction patterns, X-ray photoelectron spectra, and field-emission transmission electron microscope images confirmed that HfO_xN_y nanoparticles were dispersed onto commercial carbon black, Vulcan XC-72. The stability of HfO_xN_y-C in 0.1 mol dm^<-3> H_2SO_4 at 303 K was evaluated by measuring the mass ratio of dissolved hafnium to immersed HfO_xN_y-C using inductively coupled plasma atomic emission spectroscopy. It saturated at a low level of 0.8-4.0 mg g^<-1> with increasing immersion time up to ~24 h. The oxygen reduction reaction (ORR) activity and rate were evaluated by obtaining cyclic voltammograms and rotating disk electrode voltammograms, respectively. The HfO_xN_y-C exhibited higher ORR activity and a lower Tafel slope than NH_3-treated C under identical conditions, demonstrating that HfO_xN_y is active toward ORR. The ORR activity most depended on the heating temperature. The ORR rate increased with increasing the heating time at 1223 K which could be due to the increased y in HfO_xN_y-C. The maximum onset potential for ORR was 0.78 V vs. standard hydrogen electrode, which is 0.18 V lower than that of carbon-supported platinum, demonstrating that HfO_xN_y is promising candidate for use as an ORR catalyst for polymer electrolyte membrane fuel cell cathodes.

通过将浸渍法制备的碳载氧化铪在不同条件下的 NH3 气体中加热，合成了高度稳定的碳载氮氧化铪 (HfO_xN_y-C)。 X射线衍射图、X射线光电子能谱和场发射透射电子显微镜图像证实HfO_xN_y纳米粒子分散在商用炭黑Vulcan XC-72上。通过使用电感耦合等离子体原子发射光谱法测量溶解的铪与浸入的HfO_xN_y-C的质量比来评估HfO_xN_y-C在303K下在0.1mol dm^-3H_2SO_4中的稳定性。随着浸泡时间增加至约24小时，其在0.8-4.0mg g^ -1 的低水平下饱和。分别通过获得循环伏安图和旋转盘电极伏安图来评估氧还原反应（ORR）活性和速率。在相同条件下，HfO_xN_y-C 比 NH_3 处理的 C 表现出更高的 ORR 活性和更低的 Tafel 斜率，表明 HfO_xN_y 对 ORR 具有活性。 ORR 活性很大程度上取决于加热温度。 ORR 速率随着 1223 K 加热时间的增加而增加，这可能是由于 HfO_xN_y-C 中 y 的增加。与标准氢电极相比，ORR 的最大起始电位为 0.78 V，比碳载铂低 0.18 V，这表明 HfO_xN_y 是用作聚合物电解质膜燃料电池阴极的 ORR 催化剂的有希望的候选者。