Dual-Interface-Induced Multi-Active Sites in Polypyrrole-Encapsulated Bimetallic Oxide Heterostructures for Enhanced Overall Water Splitting

The construction of multicomponent coupled interfaces is crucial to designing highly effective and robust bifunctional electrocatalysts for water splitting. Spinel oxides are widely used as efficient catalysts; nonetheless, their catalytic activity requires enhancement. Experimental results reveal that the interfacial coupling and synergistic effect between the conductive PPy and Co3O4/CoMoO4, characterized by tunable electronic configuration, enhance charge transport and optimize the electronic structure of the coupled interface. This integrated PPy can improve the conductivity and ensure the durability of Co3O4/CoMoO4-PPy. Thanks to the advantages mentioned above, the obtained Co3O4/CoMoO4-PPy (CoO/CoMoO-PPy) exhibits exceptional catalytic properties with overpotentials of 76 mV for the hydrogen evolution reaction (HER) and 270 mV for the oxygen evolution reaction (OER) at 10 mA cm–2. Remarkably, the assembled CoO/CoMoO-PPy||CoO/CoMoO-PPy acquires only 1.59 V at 10 mA cm–2 in 1.0 M KOH with a durability of 40 h. This study provides a significant reference for designing bimetallic oxide/polymer catalysts toward high-efficiency overall water splitting.