无机材料学报 ›› 2023, Vol. 38 ›› Issue (5): 511-520.DOI: 10.15541/jim20220684

• 研究论文 • 上一篇    下一篇

自组装制备PtIr合金气凝胶及其高效电催化氨氧化性能

张祥松(), 刘业通, 王永瑛, 武子瑞, 刘振中, 李毅(), 杨娟()   

  1. 江苏大学 材料科学与工程学院, 镇江 212013
  • 收稿日期:2022-11-16 修回日期:2023-01-04 出版日期:2023-01-11 网络出版日期:2023-01-11
  • 通讯作者: 李 毅, 讲师. E-mail: liyi5482@ujs.edu.cn;
    杨 娟, 教授. E-mail: yangjuan6347@ujs.edu.cn
  • 作者简介:张祥松(1996-), 男, 硕士研究生. E-mail: jsdaujszxs1996@163.com
  • 基金资助:
    国家自然科学基金(51972150);江苏省自然科学基金(SBK20210769);中国博士后科学基金(2022M711543);江苏大学2022年大创项目(202210299366X)

Self-assembled Platinum-iridium Alloy Aerogels and Their Efficient Electrocatalytic Ammonia Oxidation Performance

ZHANG Xiangsong(), LIU Yetong, WANG Yongying, WU Zirui, LIU Zhenzhong, LI Yi(), YANG Juan()   

  1. School of Materials and Engineering, Jiangsu University, Zhenjiang 212013, China
  • Received:2022-11-16 Revised:2023-01-04 Published:2023-01-11 Online:2023-01-11
  • Contact: LI Yi, lecturer. E-mail: liyi5482@ujs.edu.cn;
    YANG Juan, professor. E-mail: yangjuan6347@ujs.edu.cn
  • About author:ZHANG Xiangsong (1996-), male, Master candidate. E-mail: jsdaujszxs1996@163.com
  • Supported by:
    National Natural Science Foundation of China(51972150);Natural Science Foundation of Jiangsu Province(SBK20210769);China Postdoctoral Science Foundation(2022M711543);2022 Creative Project of Undergraduate Student at Jiangsu University(202210299366X)

摘要:

氨具有低成本、易液化和高体积能量密度等特点, 是一种有吸引力的无碳燃料, 用其制成的直接氨燃料电池也备受科研人员青睐, 却受限于阳极氨氧化缓慢的动力学过程。本工作采用无表面活性剂的简单方法通过纳米颗粒(NPs)自组装制备了三维多孔网络结构的PtIr合金气凝胶高效氨氧化催化剂。该结构提供了丰富开放的互联质子传输通道和额外的催化活性位点, 有助于氨电催化氧化中NH3分子的去质子化过程。当Pt和Ir物质的量比为80/20时, PtIr合金气凝胶展现出最优的氨氧化(AOR)催化活性。实验通过研究NH3浓度和工作温度对催化剂氨氧化性能的影响发现, Pt80Ir20合金气凝胶催化剂的AOR性能随着氨水浓度或温度的上升而增强, 如当氨水浓度为0.5 mol/L时, 合金催化剂在0.5 V电位下的质量比活性为44.03 A·g-1, 约是0.05 mol/L 氨水中的4倍。当温度上升至80 ℃ 时, 合金催化剂在0.5 V电位下的质量比活性为148.73 A·g-1, 约为25 ℃下的12倍。在此温度变化区间, 其AOR起始电位下降了40 mV。利用Arrhenius方程计算发现, Pt80Ir20合金气凝胶催化剂的AOR反应活化能比商业Pt/C催化剂降低了~9.43 kJ·mol-1。此外, 催化材料的稳定性测试结果表明, Pt80Ir20合金气凝胶催化剂经2000次循环伏安测试后的峰值质量比活性损失为~50.6%, 优于商业Pt/C催化剂(~74.9%)。

关键词: 自组装, PtIr合金, 气凝胶, 电催化氨氧化反应

Abstract:

Ammonia with low cost, easily liquefied and high volumetric energy density is an attractive carbon-free fuel. Utilizing ammonia as anodic fuel, direct ammonia fuel cells are showing great interests to researchers. However, such amazing fuel cell device is limited by the sluggish anodic ammonia oxidation reaction. In this work, PtIr alloy aerogels with a three-dimensional porous network structure were prepared by nanoparticles (NPs) self-assembled under a simple and surfactant-free conditions. This structure provided a rich open interconnected proton transport channel and additional catalytically active sites which contributed to the dehydrogenation process of NH3 molecules in ammonia electrocatalytic oxidation. An optimal AOR activity was achieved at the 80/20 molar ratio of Pt/Ir. Effects of NH3 concentration and operating temperature on catalyst's ammonia oxidation performance were studied, which revealed that the AOR performance of Pt80Ir20 alloy aerogel was improved with the increase of ammonia concentration or operating temperature. For example, the mass specific activity, at 0.50 V of the Pt80Ir20 alloy aerogel, was estimated to be 44.03 A·g-1, which was about 4 times as that of the ammonia concentration at 0.05 mol/L. In the case of operating temperature effect, the mass activity was estimated to be 148.73 A·g-1, which was almost 12 times as that of the temperature rising (from 25 ℃) to 80 ℃. Encouragingly, the onset potential of the optimal Pt80Ir20 alloy aerogel catalyst displayed about 40 mV reduction during such a temperature change. Further calculations using the Arrhenius equation showed that its activation energy was reduced by about 9.43 kJ·mol-1 as compared with commercial Pt/C. Moreover, its AOR stability was improved as evidenced by a loss of ~50.6% mass activity after 2000 potential cycles when compared with commercial Pt/C (~74.9%).

Key words: self-assembly, PtIr alloy, aerogel, electrocatalytic ammonia oxidation reaction

中图分类号: