Tuning the Surface Composition of Ni/meso-CeO2 with Iridium as an Efficient Catalyst for Hydrogen Generation from Hydrous Hydrazine

Graphical Are two metals better than one? Surface modification of a Ni nanocatalyst by Ir results in remarkably improved catalytic properties towards H 2 generation from N 2 H 4 ⋅ H 2 O. Coupled experimental and theoretical studies reveal that the formation of Ni−Ir alloy on the catalyst surface plays a crucial role in determining the catalytic performance (see figure). Selective decomposition of hydrous hydrazine (N 2 H 4 ⋅ H 2 O) over metal catalysts provides a promising means for onboard or portable hydrogen source applications. Studies on N 2 H 4 ⋅ H 2 O decomposition catalysts mainly focus on the effects of bulk composition and structure on their performances, instead of the surface-composition-dependent properties. Herein, the synthesis of an Ir-modified Ni/ meso -CeO 2 catalyst is reported by using a combination of colloidal solution combustion synthesis and galvanic replacement methods. A combination of structural characterization, control experiments, and DFT calculations reveals that the Ni−Ir alloy resulting from calcination treatment exerts a profound effect on the catalytic properties. The resulting Ni@Ni−Ir/ meso -CeO 2 catalyst shows excellent catalytic performance towards hydrogen generation from N 2 H 4 ⋅ H 2 O, which compares favorably with the Ni−Ir bimetallic catalysts reported to date.