N.D. Zelinsky Institute of Organic Chemistry of Russian Academy of Sciencie, 47 Leninsky pr., 119991 Moscow, Russia.
Phys Chem Chem Phys. 2011 Apr 21;13(15):6892-900. doi: 10.1039/c0cp02088e. Epub 2011 Mar 10.
The results of a DRIFT study of carbon monoxide molecular adsorption and hydrogen dissociative adsorption on gallium-modified mordenite and MFI (ZSM-5) zeolites are presented. It was found that in the reduced gallium-modified mordenite (Ga-MOR) both Ga(3+) and Ga(+) exchanged cations are present and can be detected by CO adsorption. Ga(3+) cations in Ga-MOR dissociatively adsorb molecular hydrogen at elevated temperatures, resulting in the formation of gallium hydride species and acidic hydroxyl groups. In the reduced Ga-MFI evacuated at 823 K under medium vacuum conditions only Ga(+) exchanged intrazeolite cations were detected. It was found, however, that Ga(3+) intrazeolite exchanged cations which form upon high-temperature disproportionation of Ga(+) cations in the reduced Ga-MFI and Ga-MOR can be stabilized by high-temperature oxidation of these zeolites.
介绍了一氧化碳分子吸附和氢气离解吸附在镓改性丝光沸石和 MFI（ZSM-5）沸石上的 DRIFT 研究结果。结果发现，在还原的镓改性丝光沸石（Ga-MOR）中，同时存在 Ga(3+)和 Ga(+)交换阳离子，可以通过 CO 吸附检测到。Ga-MOR 中的 Ga(3+)阳离子在高温下离解吸附氢气，形成氢化镓物种和酸性羟基基团。在中真空条件下于 823 K 下抽真空还原的 Ga-MFI 中，仅检测到 Ga(+)交换的沸石内阳离子。然而，发现可以通过这些沸石的高温氧化稳定形成于还原的 Ga-MFI 和 Ga-MOR 中 Ga(+)阳离子高温歧化的 Ga(3+)沸石内交换阳离子。
