A direct synthesis of nickel nanoclusters embedded on multicomponent mesoporous metal oxides and their catalytic properties for glycerol steam reforming to hydrogen

Nickel nanoclusters embedded in multicomponent mesoporous metal oxides (Ni-MMOs) are obtained at various support compositions by a single-step synthesis of Ni ion incorporated mesoporous metal oxides (NiO-MMOs) followed by selective reduction of the NiO to Ni metal clusters. The resultant Ni-MMOs catalysts displayed enhanced Ni dispersion with well-developed mesopore structures at various support composition, exhibiting superior catalytic properties when compared to a siliceous SBA-16-supported Ni catalyst prepared by a conventional impregnation method. Glycerol steam reforming conducted at 873 K on 1Ni-2Al₂O₂-2ZrO₂ and 1Ni-2SiO ₂-2ZrO₂ catalysts exhibited considerably higher glycerol conversions over the 10 wt%-Ni/SBA-16 catalyst with similar Ni loading amount. This was primarily due to the enhanced Ni dispersion resulting from the direct synthesis process. The multicomponent mesoporous supports also significantly affect product selectivity, favoring higher hydrogen concentration in the product stream. The water-gas shift reaction appears to be positively affected by the 2Al₂O₂-2ZrO₂ and 2SiO ₂-2ZrO₂ multicomponent metal oxide matrices, which facilitated the conversion of the CO produced by the glycerol reforming further to additional hydrogen. Direct single-step synthesis of Ni-MMO catalysts was effective in enhancing the dispersion of Ni nanoclusters, as well as variation of the support components of the mesoporous catalyst systems.