Unveiling superior overall water splitting via electrooxidative leaching of Mo-Induced surface reconstruction in hierarchical CoMoO4@CoFe-LDH heterostructure

The global energy transition driving an urgent need for sustainable renewable energy technologies. Hydrogen’s role as a clean, high-efficiency energy vector stems from its ability to store large amounts of energy without generating carbon emissions, relies on water electrolysis technology for its efficient production. However, commercial noble metal catalysts (IrO 2 and RuO 2 ) have drawbacks such as high cost and poor stability, limiting their large-scale application. To address this, this study developed a hierarchical CoMoO 4 @CoFe-LDH heterostructure catalyst aimed at simultaneously optimizing oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) performance to achieve efficient overall water splitting. A core–shell structure was constructed through a dual-stage synthesis procedure (hydrothermal growth of CoMoO 4 nanorod arrays followed by electrodeposition of CoFe-LDH nanosheets). In situ analysis revealed that Mo species dissolution during the OER process induces surface reconstruction, generating highly active Co(Fe)OOH species, significantly lowering the reaction energy barrier. Experimental results showed that the catalyst exhibited outstanding OER activity and HER activity. Additionally, the catalyst exhibits outstanding stability (OER continuous operation for 50 h without degradation) and achieves efficient Overall Water Splitting Performance (starting voltage 1.52 V at 10 mA/cm 2 ). Density functional theory (DFT) calculations further confirm the optimized electronic structure at the heterointerface.