Controlled synthesis of N–CuCo2S4@Ni3S2 nanoarrays as promising urea oxidation electrocatalyst

One of the most attractive means for mitigation of environmental pollution is to produce hydrogen by electrocatalytic urea splitting. In the paper, the heterogeneous interfacial rich N–CuCo 2 S 4 @Ni 3 S 2 material was in situ synthesized on nickel foam through a typical hydrothermal and sulfuration process. This N–CuCo 2 S 4 @Ni 3 S 2 electrode displays excellent urea oxidation performance (potential of 1.38 V@50 mA cm −2 ), which is one of the best reactivity reported so far. Experimental results show that the superior catalytic activity is attributed to the rapid charge transfer, more reaction center exposed and superior electrical conductivity . Density functional theory shows that this Ni 3 S 2 material accelerates the reaction rate in the catalytic process, the introduction of this N–CuCo 2 S 4 material improves the conductivity of the material, and the synergistic catalysis of the N–CuCo 2 S 4 and Ni 3 S 2 makes this N–CuCo 2 S 4 @Ni 3 S 2 material exhibit superior urea oxidation activity. Notably, long-term tests have shown a decrease in catalytic activity, which suggests that the surface of the sulfide is in situ generated to oxides or hydroxides, which are truly active species. This work provides a new idea for the development of efficient and stable urea oxidation catalysts for sulfides.