Enhancing Alloyed Nickel Sites via Heterogeneous CoP₃–Ni₂P Modification for Highly Efficient Urea Electrooxidation

To align with the high-energy conversion efficiency in the electrochemical synthesis of hydrogen carriers, it is pivotal to boost the reaction kinetics of the anode in the electrolytic cell. Electrocatalytic urea oxidation reaction (UOR) has gained attention as a promising alternative anode reaction to water oxidation due to its small theoretical oxidation potential. However, the application of UOR is confronted with great challenges due to the unsatisfactory current under a low potential. Herein, we developed a self-supported electrode, heterogeneous cobalt phosphide, and nickel phosphide-modified nickel–cobalt alloy nanotube arrays with nickel foam as skeleton support (CoP3–Ni2P–CoxNi1–x NTAs/NF) to improve the UOR performance by optimizing the local charge distribution of active Ni sites. The CoP3–Ni2P–CoxNi1–x NTAs/NF electrode exhibited excellent UOR activity with a low potential of 1.36 V (vs RHE) at 100 mA cm–2. Surface structure analysis and electrochemical in situ Raman results revealed that synchronous CoNi alloying and heterogeneous CoP3–Ni2P introduction boosted the formation of the active Ni3+–O species caused by the modulated surface electronic structure of Ni atoms, thus accelerating the interfacial electrocatalysis. This work presents a new option for template synthesis catalysts for efficient urea oxidation reactions.