Controllable transition engineering from homogeneous NiSe2 nanowrinkles to heterogeneous Ni3Se4/NiSe2 rod-like nanoarrays for promoted urea-rich water oxidation at large current densities

The fundamental understanding of the transition from a homogeneous nanostructure to a heterogeneous one is essential for controllably exploiting the heterostructure catalysts, however, it still remains a challenge. Herein, through simply tailoring the selenization temperature, for the first time we achieve the controllable transition engineering from the homogeneous NiSe2 nanowrinkles (NiSe2 NWs) to heterogeneous Ni3Se4/NiSe2 nanorods (Ni3Se4/NiSe2 NRs) on Ni foam substrate. The unique rod-like nanoarray architecture with high surface roughness can greatly improve the mass transport efficiency. More importantly, the density function theory calculations decipher that the electron redistribution spontaneously takes place at the interfacial region between Ni3Se4 and NiSe2, which could optimize the adsorption/desorption of reaction intermediates and decrease the Gibbs free energy of rate determining step for urea oxidation reaction (UOR). As a consequence, the heteroge-neous Ni3Se4/NiSe2 NRs manifests superior UOR performance than its counterpart of homogeneous NiSe2 NWs, especially at large current densities.