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.