2D NiFe/CeO₂ Basic-Site-Enhanced Catalyst via in-Situ Topotactic Reduction for Selectively Catalyzing the H₂ Generation from N₂H₄·H₂O

An economical catalyst with excellent selectivity and high activity is eagerly desirable for H 2 generation from the decomposition of N 2 H 4 ·H 2 O. Here, a bifunctional two-dimensional NiFe/CeO 2 nanocatalyst with NiFe nanoparticles (∼5 nm) uniformly anchored on CeO 2 nanosheets supports has been successfully synthesized through a dynamic controlling coprecipitation process followed by in-situ topotactic reduction. Even without NaOH as catalyst promoter, as-designed Ni 0.6 Fe 0.4 /CeO 2 nanocatalyst can show high activity for selectively catalyzing H 2 generation (reaction rate (mol N2H4 mol –1 NiFe h –1 ): 5.73 h –1 ). As ceria is easily reducible from CeO 2 to CeO 2– x, the surface of CeO 2 could supply an extremely large amount of Ce 3+, and the high-density electrons of Ce 3+ can work as Lewis base to facilitate the absorption of N 2 H 4, which can weaken the N–H bond and promote NiFe active centers to break the N–H bond preferentially, resulting in the high catalytic selectivity (over 99%) and activity for the H 2 generation from N 2 H 4 ·H 2 O.