A Mechanistic Study of the Solid-State Reactions of H-Mordenite with Indium(0) and Indium(III)oxide

详细信息    查看全文

• 作者：Hanna Solt ; Ferenc Ló ; nyi ; R. Magdolna Mihá ; lyi ; Jó ; zsef Valyon ; Laura B. Gutierrez ; Eduardo E. Miro
• 刊名：Journal of Physical Chemistry C
• 出版年：2008
• 出版时间：December 11, 2008
• 年：2008
• 卷：112
• 期：49
• 页码：19423-19430
• 全文大小：201K
• 年卷期：v.112,no.49(December 11, 2008)
• ISSN：1932-7455

文摘

Solid-state reactions of In₂O₃/H-mordenite and In⁰/H-mordenite mixtures (Al/In = 3) were studied using an atmospheric flow-through microreactor, diffuse reflectance Fourier-transform spectroscopy (DRIFTS), and X-ray powder diffractometry (XRD). The indium(III)oxide/H-mordenite mixture was heated in a flow of 2% H₂/N₂ gas mixture or pure N₂ to 873 and 973 K, respectively. The indium(0)/H-mordenite mixture was heated in a dry and wet N₂ stream to 673−973 K. The reactions were monitored by analyzing the effluent gas, using mass spectroscopy (MS). The protons of H-mordenite were exchanged for In⁺ cations, indicating that In³⁺ was reduced and In⁰ was oxidized in the exchange processes. In the process of reductive solid-state ion exchange (RSSIE), the indium was reduced by H₂. In the oxidative solid-state ion exchange (OSSIE) process, the indium was oxidized by H₂O. Results substantiate that the ion exchange proceeds through a volatile InOH intermediate. Formation of InOH and its rapid transport within the zeolite crystals requires the presence of water vapor. The In⁺ in the zeolite lattice can be oxidized by O₂ or H₂O to indium oxycations, most probably to InO⁺, while the obtained oxycations can be reduced in hydrogen back to In⁺.