Revealing improved electrocatalytic performances of electrochemically synthesized S and Ni doped Fe2O3 nanostructure interfaces

[Display omitted] •Single-crystal-like nanostructure interfaces were achieved via a simple synthetic method.•The prepared nanostructures showed excellent electrocatalytic performance.•The enhanced performance was related to the unique physicochemical properties.•This work offers a promising process to prepare non-precious catalysts for use in acid. Non-precious-metal oxides provide various physical and chemical controllable properties when their composition and morphology are tuned for electrochemical applications. However, the unstable features due to catalytic degradation caused by the dissolution and agglomeration of the materials in acidic media have prevented the widespread use of these materials in electrocatalysis. We propose a facile and simple method for the synthesis of S and Ni co-doped single-crystal-like iron oxide nanorods (S,Ni_Fe2O3 NR) grown over a MoS2 substrate. The S,Ni_Fe2O3 NR catalyst demonstrated a stable current density of nearly −100 mA/cm2 when operated at a constant potential of −0.31 V (vs. SHE) without structural and chemical deformation of the material. The commercial Fe2O3 showed agglomerated particles after a stability test. In addition, the newly prepared S,Ni_Fe2O3 NR catalyst exhibited excellent catalytic HER performance with an overpotential of −92 mV (vs. SHE) to reach −10 mA/cm2 (a Tafel slope of 54 mV/dec). Our density functional theory (DFT) calculations suggest that a heterogeneously mixed surface with Ni and S atoms on the Fe2O3 surface can improve the HER performance. This work provides information about the design and development of future electrocatalysts with non-precious-metal oxides for use in an acidic environment.