Promotional Effect of Ni-Co/TiO2 Catalysts on CO2 Hydrogenation

The Ni-Co/TiO2 catalysts were synthesized via an excess-solution impregnation method and fully characterized XRD, FESEM, EDS, TEM, XPS and N-2 adsorption-desorption tests. In CO2 hydrogenation reaction for 3 h, Ni-Co/TiO2 catalyst exhibited a CH4 production of 84.4 mu mol, which was enhanced by 46.3%, compared with Ni/TiO2. Results of CO2-TPD and H-2-TPR demonstrated that the introduced Co can facilitate the adsorption and activation of CO2 molecules to contribute to the CO2 hydrogenation reaction. In the activity stability tests for 5 cycles, the yield of CH4 was reduced by 20.5% over Ni/TiO2, while that over Ni-Co/TiO2 was only by 10.9%, revealing that the introduced Co can also enhance the catalytic stability for the reaction. This study may provide some guidance for the design and synthesis of high-efficiency catalysts for CO2 hydrogenation.