Synergy of adsorbates and surface-reconstructed interfaces in Fe7S8/NiS2 for efficient oxygen evolution at high current density

Fabricating highly-efficient and long-time stable catalysts for water splitting under large current density is of great significance for the industrial production of hydrogen through water splitting. Herein, a heterointerface Fe7S8/NiS2 catalyst was constructed and the impact of the interaction between in-situ generated SO42− and reconstructed interface on its activity was evaluated. As shown, SO42−, as an electron acceptor and electron bridge, greatly optimized the interface electron structure and enhanced the interface electron coupling via its interaction with the interface. Benefiting from this, the catalyst exhibited an excellent catalytic capacity at high current densities in alkaline electrolyte and only required overpotential of 281/315 mV for the OER to reach 500/1000 mA·cm−2, and sustained a stable current density of 1000 mA·cm−2 for 100 h. The experiments and DFT computations confirmed that the synergy of in-situ generated SO42− and reconstructed FeOOH-NiOOH interfaces for Fe7S8/NiS2 was responsible for its highly-performance catalytic activity and long-time durability. This work elucidates the synergistic effect of adsorbates and the heterointerfaces and has a reference value for constructing efficient and durable catalysts for water splitting.