Tuning Surface Composition of Ni-Pt/CeO2 Catalyst for Hydrogen Generation from Hydrous Hydrazine Decomposition

Hydrous hydrazine (N2H4 center dot H2O) is a water-like liquid with a high hydrogen density (8%, mass fraction), relatively low cost, and satisfactory stability under ambient conditions. Owing to these favorable attributes, N2H4 center dot H2O has attracted considerable attention as a promising hydrogen carrier for on-board or portable applications. The synthesis of highly active and selective catalysts is a central issue in developing practical hydrous hydrazine-based hydrogen generation systems. The development of high-performance catalysts requires fundamental knowledge of the correlation between the surface composition of the catalyst and its catalytic performance. In the present work, a supported Ni-Pt/CeO2 bimetallic nanocatalyst was prepared by a one-pot co-reduction method, and its use for catalyzing hydrous hydrazine decomposition to generate hydrogen was reported. The surface composition of the Ni-Pt/CeO2 catalyst was regulated by heat treatments under different atmospheres, such as air, NH3, H-2, and CO and at different temperatures. It was found that changing the annealing conditions may result in altered Ni/Pt ratio at the catalyst surface, and as a consequence the catalytic performance can be tailored. When the molar Ni/Pt ratio at the catalyst surface was 0.8 similar to 1.14, the catalyst has been found to possess remarkable catalytic activity towards hydrous hydrazine decomposition. Additionally, it was found that incorporation of non-metallic N element on the catalyst surface may result in remarkably improved catalytic activity of NiPt/CeO2 towards hydrous hydrazine decomposition. This finding may open new avenues for the development of high-performance catalyst for promoting hydrogen generation from hydrous hydrazine.