Dual-Driven Activation of High-Valence States in Prussian Blue Analogues Via Graphene-Quantum Dots and Ozone-Induced Surface Restructuring for Superior Hydrogen Evolution Electrocatalyst

Abstract

Electrochemical water splitting is a pivotal process for sustainable hydrogen energy production, relying on efficient hydrogen evolution reaction (HER) catalysts, particularly in acidic environments, where both high activity and durability are crucial. Despite the favorable kinetics of platinum (Pt)-based materials, their performance is hindered under harsh conditions, driving the search for alternatives. Due to their unique structural characteristic, Prussian blue analogs (PBAs) emerge as attractive candidates for designing efficient HER electrocatalysts. However, modulating their properties and functionalities is crucial to overcome their conductivity issue. Herein, a reconfiguration strategy for the dual-driven surface restructuring of the CoFe PBA involving graphene quantum dots (GQD) and UV/ozone is proposed. X-ray absorption spectroscopy (XAS) analysis revealed that dual-driven reconstruction plays a pivotal role in promoting the high-valence metal ions, effectively reducing charge transfer resistance—a key limitation in HER. The optimized CoFe PBA/GQD-UV exhibits remarkable electrocatalytic performance toward HER, with a low overpotential of 77 mV to reach a current density of 10 mA cm⁻² with excellent durability for 12 h under an extremely high current density of 500 mA cm⁻² in an acidic solution. This dual-combination strategy offering a new pathway to develop highly active electrocatalysts.