Fabrication of Ni ₂ Fe-LDHs@WO ₃ Composite Photoanodes via Low-Dimensional Engineering toward Enhanced PEC-OER Performance

The development of cost-effective and efficient photoanodes is essential for advancing photoelectrochemical oxygen evolution reaction (PEC-OER) technology. Herein, we report the successful fabrication of Ni2Fe layered double hydroxides (Ni2Fe-LDHs)@WO3 composite photoanodes via a combined approach of ultrasonication-assisted exfoliation and electrostatic self-assembly techniques. The composite was constructed from WO3 nanosheets derived from WO2Cl2 dissociation and Ni2Fe-LDHs nanosheets obtained through exfoliation of bulk Ni2Fe-LDH. Detailed characterization revealed a densely packed, scale-like morphology and strong electronic coupling within the fabricated heterostructured material, facilitating enhanced photon harvesting, optimized charge transport, and accelerated reaction kinetics. Electrochemical tests demonstrated that the composite exhibited a remarkable photocurrent density of 3.62 mA cm–2 at 1.23 V vs RHE, nearly seven times higher than that of pristine WO3. Mechanistic analyses highlighted that the introduction of Ni2Fe-LDHs created a favorable built-in electric field and promoted the formation of high-valence Ni species, significantly enhancing the PEC-OER performance. This study provides a novel strategy for developing advanced solar-driven water splitting materials.