Highly Dispersed N-Doped Graphene Quantum Dot-Assisted NiFe Bimetallic Sites for Efficient Water Oxidation

Electrochemical water splitting for hydrogen production is a key technological route toward the large-scale generation of green hydrogen. However, the anodic oxygen evolution reaction (OER) suffers from sluggish kinetics and high overpotential, necessitating the development of non-noble metal catalysts that simultaneously possess low cost, high activity, and excellent stability. In this work, a nitrogen-doped graphene quantum dots@nickel-iron layered double hydroxide (N-GQDs@NiFe-LDH) composite catalyst was in situ constructed via a facile hydrothermal strategy. Benefiting from the electronic modulation and structural confinement effects of N-GQDs, the intrinsic catalytic activity and structural stability of the catalyst were simultaneously enhanced. The as-prepared catalyst requires an overpotential of only 320 mV to deliver a current density of 500 mA cm^-2 and maintains 98% of its initial activity after 100 h of chronoamperometric stability testing, demonstrating promising potential for practical applications. Multiscale characterizations revealed that N-GQDs formed strong electronic interactions with Ni/Fe active sites at the interface, significantly enhanced interfacial electron transport, and accelerated the OER kinetics. This study demonstrates that the N-GQDs@NiFe-LDH catalytic system constructed via an interfacial heterostructure engineering strategy provides a new insight for the rational design and development of efficient non-noble-metal OER electrocatalysts.