Heterostructure engineering of the Fe-doped Ni phosphides/Ni sulfide p-p junction for high-efficiency oxygen evolution

Regulating charge distribution through heterostructure engineering is an encouraging approach to achieving efficient alkaline water electrolysis. Here, a Fe-doped Ni phosphides/Ni sulfide p-p heterojunction (NiFe-PS) for oxygen evolution reaction (OER) is constructed on nickel foam. It is shown that the built-in electric field at the interface of Fe-doped Ni phosphides/Ni sulfide facilitates the charge transfer and modifies the electronic properties of the catalyst, thereby enhancing its conductivity and catalytic activity. Profiting from the rational electronic structure modulation, the designed NiFe-PS electrode possesses excellent OER performance among phosphides with low overpotentials of 204 and 256 mV at current densities of 10 and 100 mA cm(-2), respectively. Meanwhile, the prepared catalyst displays high stability in the long-term chronopotentiometric test (125 h @ 100 mA cm(-2)). Structural characterizations confirm that the outer phosphide layer can withstand long-term surface oxidation and operate as a robust shield to prevent oxidation of the inner sulfide, ensuring rapid electron transport within the catalyst throughout the OER process. (C) 2022 Elsevier B.V. All rights reserved.

Automated summary

Regulating charge distribution through heterostructure engineering is an effective approach for achieving efficient alkaline water electrolysis. In this study, a Fe-doped Ni phosphides/Ni sulfide p-p heterojunction electrode was constructed on nickel foam, which exhibited enhanced conductivity and catalytic activity due to the built-in electric field and modified electronic properties at the interface. The designed NiFe-PS electrode demonstrated excellent oxygen evolution reaction (OER) performance with low overpotentials and high stability, attributed to the rational electronic structure modulation and the robust phosphide layer preventing oxidation.