P-Doped Metal–Organic Framework (MOF)-Derived Co3O4 Nanowire Arrays Supported on Nickle Foam: An Efficient Urea Electro-Oxidation Catalyst

The urea electro-oxidation reaction (UOR) is emerging as a new energy conversion technology and a promising method for alleviating water eutrophication problems. However, a rationally designed structure of the electrode materials is urgently required to achieve high UOR performance. Herein, P-doped MOF-derived Co3O4 nanowire arrays grown on nickel foam (P-Co3O4/NF) are successfully synthesized via the growth of Co-MOF and subsequent calcination followed by phosphorization treatment. Owing to the optimized electronic structure, the as-prepared P-Co3O4/NF composite exhibits much higher UOR electrocatalytic performance than the undoped Co3O4/NF sample. Beyond this, the meticulous structure of the one-dimensional nanowire arrays and the three-dimensional skeleton structure of nickel foam contribute to the enhanced electrocatalytic activity and stability toward UOR. As a result, the P-Co3O4/NF composite displays a low overpotential of 1.419 V vs. RHE at 50 mA cm−2, a small Tafel slope of 82 mV dec−1, as well as favorable long-term stability over 65,000 s in 1.0 M KOH with 1.0 M urea. This work opens a new avenue in designing non-precious electrocatalysts for high-performance urea electro-oxidation reactions.