Modulating the methanation activity of Ni by the crystal phase of TiO2

We demonstrate that the methanation activity of Ni catalysts is modulated by the crystal phase of the TiO2 support. The rutile TiO2 (r-TiO2)-supported Ni catalyst gives a turnover frequency almost two orders of magnitude higher than the anatase TiO2 (a-TiO2)-supported catalyst although the two catalysts exhibit a similar mean Ni particle size. Characterization by H2-TPR, H2-TPD, XPS and IR reveals a stronger interaction between Ni and r-TiO2, leading to a higher capability of CO activation and hydrogenation activity of Ni although Ni is partially covered by TiOx overlayers during reaction. Interestingly, the modulating effects of the titania crystal phases are much more pronounced on the activity of Ni in CO2 methanation.