Electrostatic adsorbing graphene quantum dot into nickel-based layered double hydroxides: Electron absorption/donor effects enhanced oxygen electrocatalytic activity

Exploring electrocatalysts with optimal electronic structure and understanding the relationship between electronic structure and activity are highly required for designing advanced OER catalysts. Recently, introducing nanocarbon materials into LDHs has been demonstrated as an effective way to improve the OER activity; however, deeply understanding the regulating effect of nanocarbon on the electronic structure of LDHs is still a critical challenge. Herein, it is reported that the regulating of the surface electronic structure of nickel-based layered double hydroxides (NiM-LDHs (M = Fe, Co, Mn)) by adsorbing graphene quantum dot (GQDs). The Ni-based LDHs/GQDs delivers enhanced OER activity, and particularly NiFe LDH/GQDs achieves an ultralow overpotential of 189 mV (10 mA cm-2) and superior performance in rechargeable Zn-air battery tests. Combining with theoretical calculations and X-ray photoelectron spectroscopy, we ascribe the excellent OER activity of Ni-based LDHs/GQDs to the strong interaction between NiFe LDH and GQDs, which changes the charge distribution around metal ions and triggers the charge accumulation of the active Ni species. The above results demonstrate the significance of controlling the surface electronic structure for designing advanced 3d metal electrocatalysts.

Automated summary

Introducing graphene quantum dots to regulate the surface electronic structure of nickel-based layered double hydroxides (NiM-LDHs) has been shown to enhance oxygen evolution reaction (OER) activity. This change in charge distribution around metal ions triggers the accumulation of active nickel species, leading to improved OER performance.