Hydrogen on polycrystalline β-Ga2O3:: Surface chemisorption, defect formation, and reactivity

被引：68

作者：

Jochum, Wilfrid ^{[1
]}

Penner, Simon ^{[1
]}

Foettinger, Karin ^{[2
]}

Kramer, Reinhard ^{[1
]}

Rupprechter, Guenther ^{[2
]}

Kloetzer, Bernhard ^{[1
]}

机构：

[1] Univ Innsbruck, Inst Phys Chem, A-6020 Innsbruck, Austria

[2] Vienna Univ Technol, Inst Matchem, A-1210 Vienna, Austria

来源：

JOURNAL OF CATALYSIS | 2008年 / 256卷 / 02期

关键词：

gallium oxide; beta-Ga2O3 hydrogen adsorption; defect formation; thermal desorption spectroscopy; temperature-programmed reduction; electric impedance spectroscopy; infrared spectroscopy;

D O I：

10.1016/j.jcat.2008.03.019

中图分类号：

O64 [物理化学（理论化学）、化学物理学];

学科分类号：

070304 ; 081704 ;

摘要：

The adsorption of H-2 and H2O on differently pretreated beta-Ga2O3 samples, exhibiting variable surface chemistry and surface defect concentration, was studied by temperature-programmed reduction. oxidation, and desorption; Fourier transform infrared spectroscopy; and electric impedance measurements. Adsorption of H-2 at 300-473 K resulted in the formation of surface -OH groups with no formation of oxygen defects. Between 473 and 550 K, formation of Ga-H species was observed. At above 550 K, oxygen vacancy/defect formation was observed, resulting in enhanced formation of Ga-H species, accompanied by the formation of more strongly bound Ga-H species. H2O Was observed to quench oxygen vacancies formed by reductive pretreatment and to exhibit a strong hydrolytic affinity to H adsorbed on Ga sites. The effect of water was seen even under strongly reducing conditions (773 K: 1 bar H-2) with only traces of water present. (c) 2008 Elsevier Inc. All rights reserved.

引用

页码：268 / 277

页数：10

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