Dependence of the strong metal-support interactions of Ni/TiO2 and the induction period of glycerol steam reforming on the dynamic crystal phase evolution

The dynamic relationship of TiO 2 crystal phase and strong metal-support interactions (SMSI) of Ni/TiO 2 catalyst was investigated to reveal the induction period of glycerol steam reforming. Comprehensive investigations confirmed that the SMSI between Ni 0 and anatase TiO 2 was formed by anatase TiO 2 encapsulated Ni 0 after H 2 reduction at 500 °C for the Ni/TiO 2 catalyst calcined at 500 °C (Ni/Ti-500R), which inhibited the contact of Ni 0 active sites with reactants and led to the low hydrogen yield in the initial stage of the reaction. Interestingly, the dynamic conversion of anatase to rutile during the GSR process at 600 °C caused the TiO 2 overlayers on the Ni 0 particles to gradually fade, exposing more Ni 0 sites, resulting in a gradual increase in hydrogen yield to 5.93 mol H2 /mol glycerol . In addition, Ni/Ti-500R with a dynamic SMSI inhibited Ni 0 particles sintering and encapsulated carbon deposition, resulting in relatively better stability (21 h) after induction period. In comparison, the designed Ni/TiO 2 catalyst calcined at 600 °C (Ni/Ti-600R) with rutile TiO 2 as the main component inhibited the formation of the classical SMSI, even after 600 °C H 2 reduction, and no excessive TiO 2 encapsulated Ni 0 particles were observed, so no obvious induction period occurred. This study provides new insights into the relationship of SMSI with crystal phases and the induction period in multiphase catalysis, also a new strategy for designing efficient catalysts.