Engineering 2D/1D Ni3Co1-LDH/CNTs heterostructures for energy-efficient urea electrooxidation

A practical strategy to reduce the energy required for electrocatalytic hydrogen production is to replace the sluggish anodic oxygen evolution reaction (OER) with the thermodynamically more favorable urea oxidation reaction (UOR). Herein, a durable Ni 3 Co 1 -layered double hydroxide/carbon nanotube (Ni 3 Co 1 -LDH/CNTs) electrocatalyst was engineered by integrating two-dimensional LDH with a highly conductive one-dimensional CNT network, creating a composite with abundant interfacial structures. This design increases the specific surface area, fully exposes the active sites, and accelerates electron transfer, enabling the Ni 3 Co 1 -LDH/CNTs composite to exhibit remarkable urea oxidation activity. The 2D/1D composite electrode reduced the urea oxidation potential by nearly 300 mV at a current density of 50 mA cm −2 . To demonstrate its practical application, a two-electrode electrolyzer was assembled for urea-assisted water electrolysis, which showed stable performance for 49 h. To understand the mechanism of electrocatalytic urea oxidation, a plausible mechanism was proposed with the support of ex situ FTIR analysis, suggesting that urea oxidation led to the formation of carbonate. These results suggest the potential of the LDH/CNTs catalyst for energy-efficient hydrogen production via urea-assisted water electrolysis. This work provides a clear method for developing non-precious transition-metal catalysts for promising applications, including simultaneous wastewater treatment and energy-efficient hydrogen production.