Modulating nanostructure and electronic structure of P and W co-doped carbon encapsulated heterovalent NiCo composite for accelerating urea oxidation reaction

The primary intermediate substances of urea oxidation reaction (UOR) catalyzed by NiOOH are *CON, *CONH and *COO. However, the strong binding between Ni3+ and *COO makes *COO difficult to desorption, it is difficult for most nickel -based catalysts to meet the activity requirements. Herein, P and W co -doped carbonencapsulated NiCo (P-W-NiCo@C) nanoparticles/nanosheets structure catalysts was synthesized via hydrothermal method and calcination to enhance the activity and durability of Ni based catalysts toward UOR. As expected, the carbon -coated structure was found to facilitate the transfer of electrons from NiCo alloy to the carbon layer, while the introduction of P and W optimized the electronic structure of the central metal site. Benefiting from the co -doped, carbon -encapsulated, alloying, electron interaction and nanoparticles/nanosheets structure, P-W-NiCo@C can deliver current density of 300 mA cm -2 at 1.34 V (vs. RHE) during the UOR. Most importantly, P-W-NiCo@C as cathode and anode catalyst still has good electrochemical properties in artificial urine (E10/300 = 1.13/2.17 V), indicating that P-W-NiCo@C has potential practical application value in electrolyzing urea rich wastewater.