Interlayer Effect in NiCo Layered Double Hydroxide for Promoted Electrocatalytic Urea Oxidation

Urea electrolysis is a promising route to utilize urea-rich wastewater as an energy source to produce hydrogen on the cathode or generate electricity through a direct urea fuel cell, which offers great potential for simultaneous water remediation and energy recovery. Here, we report a scalable synthetic strategy to prepare NiCo layer double hydroxide (NiCo LDH) as an efficient catalyst for urea electrooxidation. NiCo LDH with NO3– intercalant exhibited the best electrocatalytic performance and selectivity toward urea oxidation with a low onset potential, high faradaic efficiency, and high durability. The interlayer spacing in the LDH structure was found to play a pivotal role in the urea oxidation electrocatalysis with higher activity/selectivity under larger spacings. Further analysis of the urea oxidation product could potentially enable selective urine treatment into environmentalally friendly products.