Overvoltage decrease of liquid ammonia electrolysis by electrode of nitrogen absorbing material with electrocatalysts

2018 Fiscal Year Final Research Report

• Project/Area Number: 16K18255
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Multi-year Fund
• Research Field: Structural/Functional materials
• Research Institution: Waseda University (2017-2018); University of Tsukuba (2016)
• Principal Investigator: Hanada Nobuko 早稲田大学, 理工学術院, 講師(任期付) (00606634)
• Research Collaborator: Noda Suguru ; Sugime Hisashi ; Hori Keisuke ; Akagi Natsuho
• Project Period (FY): 2016-04-01 – 2019-03-31
• Keywords: 液体アンモニア / 水素キャリア / 二元系触媒 / 電気分解

Outline of Final Research Achievements

The anode reaction with nitrogen desorption has much larger overpotential than that of a cathode reaction in the electrolysis of liquid ammonia for hydrogen generation. The anode reaction properties were investigated using mono catalyst and binary catalyst electrodes. The catalyst effect on anode reaction was investigated by focusing on the metal nitride formation enthalpy which corresponds to the strength of metal-nitrogen bond. By plotting the current density at the low potential against the metal nitride formation enthalpy, the volcano plot was obtained. The binary metal catalysts of Fe and Pt (Fe-Pt) composited in nanoparticle size or atomic size (alloyed) were prepared. The current density of both Fe-Pt electrodes were lower than that of mono-Fe and mono-Pt at the low potential.

Free Research Field

材料科学

Academic Significance and Societal Importance of the Research Achievements

水素キャリアとしての液体アンモニアから電気分解により水素を取り出す方法の研究を行った。窒素放出を伴うアノード反応の過電圧を下げるために、一元系もしくは二元系触媒電極を適用した。窒素との結合のしやすさが異なる一元系触媒金属を用いた場合は、低電位での各触媒金属における電流密度と金属窒化物生成エンタルピーの間に相関関係が得られることが明らかになった。二元系触媒は粒子レベルおよび原子レベルでの複合化の影響を調べ、今回検討したPt-Fe系触媒では、一元系触媒よりもアノード反応活性が下がることが分かった。