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

Abstract

An economical catalyst with excellent selectivity and high activity is eagerly desirable for H2 generation from the decomposition of N2H4·H2O. Here, a bifunctional two-dimensional NiFe/CeO2 nanocatalyst with NiFe nanoparticles (∼5 nm) uniformly anchored on CeO2 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 Ni0.6Fe0.4/CeO2 nanocatalyst can show high activity for selectively catalyzing H2 generation (reaction rate (molN2H4 mol-1NiFe h-1): 5.73 h-1). As ceria is easily reducible from CeO2 to CeO2-x, the surface of CeO2 could supply an extremely large amount of Ce3+, and the high-density electrons of Ce3+ can work as Lewis base to facilitate the absorption of N2H4, 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 H2 generation from N2H4·H2O.