Interface effect-boosted Ni(OH)2@CoP core–shell nanoarrays as bifunctional electrocatalyst for urea-assisted energy-saving hydrogen production via water splitting

[Display omitted] •Ni(OH)2@CoP core–shell nanoarrays structure was prepared on support of Ni foam.•E- transfer from CoP to Ni(OH)2 modulates the electronic structure of active atoms.•Interface effect optimizes the adsorption free energy to reaction intermediates.•Ni(OH)2@CoP/NF exhibits excellent HER, OER and UOR electrocatalytic performance.•The two-electrode system realizes energy-saving H2 production and urea degradation. Interface engineering is the efficacious means to modulate the electron configuration of catalytic sites, optimize the adsorption free energy to reaction species and improve the electrocatalytic performance of materials. Here, we prepared the self-supported heterogeneous CoP nanowires core-Ni(OH)2 nanosheets shell nanoarrays on nickel foam (Ni(OH)2@CoP/NF). In Ni(OH)2@CoP interface region, the heterostructure interface effect will promote the directional electrons transfer from CoP to Ni(OH)2, which realizes the electronic structure modulation of reaction sites, and thus adjust the reaction energy barrier to reaction intermediates. This is guaranteed that the Ni(OH)2@CoP/NF displays significantly boosted hydrogen evolution, oxygen evolution and urea oxidation performance. Moreover, the two-electrode system assembled by Ni(OH)2@CoP/NF shows significantly improved overall performance with the assistance of urea, which merely requires 1.57 V to run 100 mA cm−2, which is much superior to that without urea assistance (1.69 V). Simultaneously, urea will also be oxidized to carbon dioxide, nitrogen, water and other pollution-free substances. This research further shows that the construction of related heterojunction catalysts through interface engineering exhibits a considerable effect on raising catalytic performance, and provides a valuable reference for further realizing the industrial application of non-noble metal-based materials.