Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
5353422 | Applied Surface Science | 2016 | 42 Pages |
Abstract
The catalytic methanation of CO2 was carried out on Ni catalysts supported on Y-doped ZrO2 with various Y3+ concentrations and Ni/(Zr + Y) molar ratio = 1. The catalysts were characterized by X-ray diffraction, scanning transmission electron microscopy, specific surface area, temperature-programmed desorption of CO2, and temperature-programmed reaction. In addition, operando diffuse-reflectance infrared Fourier-transform spectroscopy (DRIFT) was used to identify the adsorbed reaction intermediate. Catalysts supported on Y-doped ZrO2 show higher catalytic activity than the catalyst on Y-free ZrO2 with a monoclinic ZrO2 phase. The catalytic activity is also dependent upon the Y3+ concentration, and the highest activity was obtained for the catalyst with a Y/(Zr + Y) molar ratio of 0.333, which consists mainly of fcc Ni and cubic ZrO2 phase. Y3+ doping into ZrO2 introduces oxygen vacancies, which play an important role in enhancing the catalytic activity. The operando DRIFT study reveals that a CO adsorption intermediate is absent, and bidentate carbonate is an important intermediate for CH4 formation.
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Authors
H. Takano, Y. Kirihata, K. Izumiya, N. Kumagai, H. Habazaki, K. Hashimoto,