Ultrafine Homologous Ni2P–Co2P Heterostructures via Space‐Confined Topological Transformation for Superior Urea Electrolysis

Abstract Constructing effective electrocatalysts based on ultrafine heterostructures is a promising strategy for boosting catalytic performance by exposing active sites and increasing specific surface area. However, the fabrication of catalytically active heterostructures with elaborate architectures is still poorly developed owing to synthetic challenges, and the intrinsic mechanism of heterogeneous interfaces remains unclear because of insufficient evidence regarding real active sites. In this study, ultrafine homologous Ni 2 P–Co 2 P heterostructures (Ni 2 P–Co 2 P/C) are created using a topological transformation strategy from a Ni–Co layered double hydroxide/carbon (Ni–Co LDH/C) interconnected structure in a single nanosheet. When employed as catalysts in urea oxidation reaction (UOR), the Ni 2 P–Co 2 P/C heterostructures exhibit superior activity and stability, attributed to the optimized geometric and electronic structures of the catalytic sites. Specifically, it takes an ultralow potential of 1.27 V to reach a current density of 10 mA cm −2 with a small Tafel slope of 28.71 mV dec −1 . The operando analyses and calculation results reveal that cobalt incorporation can reduce the generation potential of the surface reconstructive active species and optimize the absorption/desorption energy of the intermediates. Overall, this study proposes an efficient and cost‐effective UOR electrocatalyst and offers a new high‐performance homologous heterostructure design for widespread application.