Synchronous Electrocatalytic Design of Architectural and Electronic Structure Based on Bifunctional LDH-Co3 O4 /NF toward Water Splitting.

The rational design of highly efficient bifunctional electrocatalysts for water splitting is extremely urgent for application in sustainable energy conversion processes to alleviate the energy crisis and environmental pollution. In this work, through simple deposition of layered double hydroxides (LDH) on Co3 O4 /NF (NF=nickel foam) nanosheets arrays, hierarchical Co3+ -rich materials based on LDH-Co3 O4 /NF are prepared as highly active and stable electrocatalysts for water splitting. The NiFe-LDH-Co3 O4 /NF demonstrates excellent electrochemical activity with an overpotential of 214 mV for the OER and an overpotential of 162 mV for the HER at 10 mA cm-2 . Such a performance is attributed to the optimized electronic states with a high concentration of Co3+ , which improves the intrinsic activity, and the sheet-on-sheet hierarchical structure, which increases the number of active sites. The unique synchronous design of both the architectural and electronic structure of nanomaterials can simultaneously accelerate the reaction kinetics and provide a more convenient charge transfer path. Therefore, the strategy reported herein may open a new pathway for the design of excellent electrocatalysts for water splitting.