H2 Dissociation over NbO: The First Step toward Hydrogenation of Mg

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• 作者：Keisuke Takahashi ; Shigehito Isobe ; Somei Ohnuki
• 刊名：Langmuir
• 出版年：2013
• 出版时间：September 24, 2013
• 年：2013
• 卷：29
• 期：38
• 页码：12059-12065
• 全文大小：339K
• 年卷期：v.29,no.38(September 24, 2013)
• ISSN：1520-5827

文摘

Niobium-based oxide nanoparticles have proven to be catalytically effective toward hydrogenation of Mg where H₂ dissociation over the niobium-oxides is considered to be a crucial reaction step. However, the role of niobium oxides toward H₂ dissociation still remains unclear as to what atomic configurations are responsible for the catalytic activity. H₂ dissociation over different surface planes of Nb, NbO, and Nb₂O₅ as well as small NbO clusters is performed by using a density functional theory. The calculations reveal that H₂ dissociation, adsorption energy, and the bond type between H and surfaces (clusters) depend on the atomic configurations of Nb and O. In particular, H₂ adsorption on NbO(111) is enhanced by O atoms without forming O鈥揌 bond where the bond type of H and surface is found to be an electron pairing. Thus, NbO(111) could not only be a effective catalyst but also potentially prevent the formation of MgO during the hydrogenation of Mg. The results should be helpful in developing and tailoring the efficient catalyst toward H₂ dissociation and hydrogenation of Mg.