Dynamic and Resilient Cobalt Copper Nitride and Iron Nitride Heterostructure Aided Energy Economic Urea Electrolysis...

Urea oxidation reaction (UOR) is recognized for energy-efficient hydrogen production, which nonetheless requires a meticulously designed electrocatalyst with active sites for intermediates adsorption and gaseous products desorption to fully exploit its advantages. Herein, we design the heterostructure consisting of cobalt copper nitride and iron nitride (Co₃CuN/Fe_xN_y) as an efficient and trifunctional electrocatalyst, which requires 1.35 V_RHE, 1.55 V_RHE, and 0.23 V_RHE potentials to reach 100 mA cm^-2 current density for UOR, oxygen evolution reaction (OER), and hydrogen evolution reaction (HER), respectively. Unlike the conventional UOR selective electrocatalyst, Co₃CuN/Fe_xN_y not only facilitates the UOR → OER switching but also shows self-regulatory ability in UOR ↔ OER. The Density Functional Theory (DFT) study explained that while Co₃CuN promoted the adsorption of CO(NH₂)₂ and H₂O, Fe_xN_y facilitated CO₂ and N₂ desorption, resulting in accelerated UOR and HER kinetics. The electrocatalyst also demonstrated outstanding performance in a urea-coupled AEM electrolyzer with about 20% of power saving and great electrolyzer efficiency, further highlighting its potential for industry-relevant applications.