Regulating the electronic structure of ultrathin Ni-based chalcogenide nanosheets through iron modification towards high electrocatalytic activities

Interfacial electronic structure regulation has been shown to be beneficial for a variety of electrocatalytic reactions. However, integrating foreign species into anion vacancy defect electrocatalysts, and investigating their interfacial electron structure and synergistic catalytic effect are still somewhat controversial. Herein, Fe2O3/ NiSe2 and Fe2O3/Ni3S2 heterostructures catalysts with abundant anion defects (Se, S) were constructed through an efficient spatial combination of primary hydroxide nanosheets. The Fe2O3/NiSe2 and Fe2O3/Ni3S2 catalysts exhibited outstanding electrocatalytic activities, as shown by the overpotentials of 200 mV at 100 mA cm-2 for OER, and 60 mV at 10 mA cm-2 for HER, respectively. The Fe2O3/NiSe2 (anode)?Fe2O3/Ni3S2 (cathode) device accelerated water splitting at 1.54 V with 10 mA cm-2, surpassing the integrated couple of Pt and Ir-based oxide (1.57 V). The chemical valence state, combined with DFT calculations, revealed that interface engineering and anion defects could modulate the electronic structures of the Fe2O3 modified NiSe2 and Ni3S2 catalysts, reduce the energy barrier of intermediate, and therefore dramatically improve their catalytic performances. This work not only presents a universal strategy for the construction of active and durable electrocatalyst with abundant anion defects, but also provides a new way for the rational design of novel nanostructure for electrocatalytic applications.

Automated summary

In this study, Fe2O3/NiSe2 and Fe2O3/Ni3S2 heterostructures with abundant anion defects were successfully constructed, showing outstanding electrocatalytic activities by reducing the energy barrier of intermediates. The integration of interface engineering and anion defects significantly improved the catalytic performances of the Fe2O3-modified NiSe2 and Ni3S2 catalysts.