Spontaneous activation behavior of NiSn, an intermetallic catalyst, for hydrogen production via methanol decomposition

NiSn金属間化合物のメタノール分解に対する自発的な触媒活性化

Fan, M.*; Xu, Y.*; 櫻井 惇也*; 出村 雅彦*; 平野 敏幸*; 寺岡 有殿; 吉越 章隆 

Fan, M.*; Xu, Y.*; Sakurai, Junya*; Demura, Masahiko*; Hirano, Toshiyuki*; Teraoka, Yuden; Yoshigoe, Akitaka

NiSn単相粉末試料のメタノール分解反応に対する触媒特性を調べた。触媒反応は713K, 793K, 873Kの各温度で等温実験であった。793K以上の温度では触媒活性は時間の増加に伴い高くなることを見出した。また、NiSnはHとCOに高い選択性を示すことが分かった。表面キャラクタリゼーションの結果、触媒反応中触媒表面にNiSn微粒子が生成されることが分かった。これらの微粒子は自発活性化の原因と考えられる。

The catalytic properties of single-phase NiSn powder in the production of hydrogen via the decomposition of methanol were investigated in isothermal tests at 713, 793, and 873 K. The catalytic activity of NiSn significantly increased with time at 793 and 873 K, but not at 713 K, suggesting that NiSn is spontaneously activated at temperatures above 793 K. At these temperatures, NiSn showed high selectivity for H and CO production and low selectivity for CH, CO, and HO production, indicating that methanol decomposition was the main reaction, and that side reactions such as methanation and water-gas shift reaction were suppressed. Surface analysis revealed that fine NiSn particles were formed during the reaction, accompanied by a small amount of deposited carbon. The formation of these particles was suggested to be the cause for the spontaneous activation of NiSn.