化学
催化作用
电解
阳极
过电位
电流密度
无机化学
氨
氮化物
金属
氮气
镍
氢
分析化学(期刊)
电化学
物理化学
电极
有机化学
电解质
物理
量子力学
图层(电子)
作者
Natsuho Akagi,Keisuke Hori,Hisashi Sugime,Suguru Noda,Nobuko Hanada
标识
DOI:10.1016/j.jcat.2022.01.005
摘要
Liquid ammonia is able to release hydrogen via electrolysis with a theoretical voltage of 0.077 V. However, the actual operation voltage is much higher (around 1–2 V) due to the large overpotential of the anodic reaction. We systematically investigated Pt, Ir, Ru, Ni, Co, Fe, Ta, and Ti as the anodic catalyst, and observed a volcano correlation when plotting the current density against the formation enthalpy of metal nitrides per nitrogen ΔfHMN (kJ/mol-N). ΔfHMN reflects the strength of metal-nitrogen bond, and Ru having a moderate ΔfHMN showed the highest catalytic activity. Then, the activity enhancement via microstructure control was examined. The sputtered Pt and Ni films having a columnar structure with a rough surface showed 7- and 13-times higher current density than the Pt and Ni plates, respectively. An anodic current density of 0.45 mA/cm2 was achieved for the sputtered Ni film at an anodic potential as low as 0.3 V vs H2/NH3.
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