Nitrogen fixation under ambient temperature and pressure using a gas diffusion electrode

使用气体扩散电极在环境温度和压力下固氮

• 批准号: 07455346
• 负责人: FURUYA Nagakazu
• 金额: $ 3.84万
• 依托单位: Yamanashi University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 1995
• 资助国家: 日本
• 起止时间: 1995 至 1996
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-07455346/
• 关键词: Gas diffusion Electrode; Nitrogen fixation; Ammonia; Pd-Ru alloy catalyst; Iron catalyst; Electroreduction; Hydrogenated palladium; Pd-Ru触媒; 常温常圧

New concept to make reaction domain for activating stable N_2 molecules was proposed as described below. Reaction layr having plenty of reaction domain, in which N_2 gas, electrolyte and catalysts should exist closely each other, consists of mixture of hydrophobic portion with catalysts and hydrophilic portion. The optimization of structure and catalysts at gas-diffusion electrodes was investigated in this work.Nitrogen reduction was examined at gas-diffusion electrodes with various metallic catalysts, which were prepared by spreading their chloride solutions and then the reduction of them to the metals. The formation of ammonia was found at gas-diffusion electrodes with Pd-Ru alloy catalysts. The amount of ammonia formed is maximum at catalyst composition of Pd (50%) +Ru (50%), at which the current efficiency for ammonia formation is less than 1% and decreases with electrolyte time. Nitrogen atoms adsorbed on the catalysts were not detected by XPS measurements. Ammonia formation was not detected at pure Pd and Ru catalysts. Decrease of Pd and Ru loaded was not found using by X-ray fluorescence analysis.The reactivity at Pd-Ru catalysts was examined in gas phase in order to confirm the ammonia formation. When Pd, Ru and Pd-Ru black catalysts deposited on Pd bulk metal with hydrogen occluded were kept in pure nitrogen atmosphere, the gravimetry of these catalysts was carried out. The weight of Pd-Ru black catalysts decreases more than of Pd and Ru catalysts, i.e.this result indicates that ammonia formation can take place at Pd-Ru black catalysts.

提出了制备活化稳定N_2分子的反应域的新概念。反应层由疏水部分和亲水部分组成，具有丰富的反应域，其中N_2气体、电解质和催化剂应紧密共存。本文研究了气体扩散电极的结构和催化剂的优化，考察了不同金属催化剂在气体扩散电极上的氮还原性能。氨的形成被发现在气体扩散电极与钯钌合金催化剂。当催化剂组成为Pd（50%）+Ru（50%）时，氨生成量最大，此时氨生成电流效率小于1%，且随电解时间的延长而降低。XPS测量未检测到吸附在催化剂上的氮原子。在纯Pd和Ru催化剂下未检测到氨形成。用X射线荧光光谱分析没有发现Pd和Ru负载量的减少。在气相中考察了Pd-Ru催化剂的反应活性以证实氨的生成。在纯氮气氛下，对Pd、Ru和Pd-Ru黑催化剂进行了重量分析。Pd-Ru黑催化剂的重量比Pd和Ru催化剂减少得更多，即该结果表明在Pd-Ru黑催化剂处可以发生氨形成。