An advanced graphene quantum dot/NiFe-layered double-hydroxide for water oxidation in a neutral solution

Herein, it is reported that the nanocomposite of graphene quantum dot (GQD) and NiFe-layered double hydroxide (LDH) is a highly active and stable electrocatalyst for water oxidation. The GQD/NiFe-LDH composite was prepared using the hydrothermal method and investigated using X-ray diffraction (XRD) and Scanning electron microscopy (SEM). Based on the XRD and SEM results, the synthesis of GQD/NiFe-LDH was confirmed.  Then, the GQD/NiFe-LDH composite was applied as an effective electrocatalyst for water oxidation. The obtained results from linear sweep voltammetry (LSV) curves show that GQD/NiFe-LDH improved water oxidation reaction with the overpotential of ۳۲۳ mV in neutral media in comparison with pure NiFe-LDH, GQD, and RuO۲. The improved oxygen generation is due to the association of NiFe-LDH nano-plate with GQD. High activity of GQD/NiFe-LDH can be attributed to excellent electrical conductivity from GQD and high electrochemical activity due to the presence of NiFe-LDH. The stability of the electrocatalyst was investigated by water oxidation for ۵.۵ h.

Keywords:

Water oxidation , Graphene quantum dot , NiFe-layered double hydroxide , Nanocomposite