A Comparative Ambient Pressure X-ray Photoelectron and Absorption Spectroscopy Study of Various Cobalt-Based Catalysts in Reactive Atmospheres

作者：Turczyniak S; Luo W; Papaefthimiou V; Ramgir N S; Haevecker M; Machocki A; Zafeiratos S^*

来源：Topics in Catalysis, 2016, 59(5-7): 532-542.

DOI：10.1007/s11244-015-0531-5

• Cobalt
• Reduction
• Oxidation
• Ethanol steam reforming
• AP-XPS
• NEXAFS
• ZnO
• Ceria
• Material gap

The oxidation state of cobalt in various forms (single crystal, nanopowder, deposited on CeO2 and ZnO supports) was investigated in situ under O-2, H-2 and ethanol steam reforming (ESR) conditions (C2H6O:H2O = 1:3) by using ambient pressure X-ray photoelectron and absorption spectroscopies. In O-2 atmosphere single crystalline, nanopowder and CeO2-supported cobalt is readily oxidized into a spinel Co3O4 phase, while over the ZnO a mixed Zn1-xCoxO oxide is formed. In H-2 and ESR atmospheres, Co3O4 oxide reduces to the metallic state, with an evident effect of the gas atmosphere and the sample type in this process. On the other hand the Zn1-xCoxO oxide proved to be extremely stable in reductive conditions. Finally, under the ESR atmosphere the amount of carbon deposition and the type of the adsorbed oxygen species considerably varies between supported and single crystalline/nanopowder cobalt catalysts.

• 出版日期2016-3