LAUSR

Abstract Pyrite-type binary nickel iron diselenides (Ni0.5Fe0.5Se2) supported on carbon fiber cloth (CFC) as electrocatalysts for oxygen evolution reaction (OER) have been prepared by a facile two-step process. Firstly, binary Ni0.5Fe0.5 hydroxide nanosheets have been electrodeposited on CFC. Secondly, a solvothermal selenization process has been used to convert Ni0.5Fe0.5/CFC into Ni0.5Fe0.5Se2/CFC. XRD shows that Ni0.5Fe0.5Se2 on CFC has the typically octahedral crystalline. XPS proves the existence and valence of Ni, Fe and Se. SEM images show that Ni0.5Fe0.5Se2 has novel pyrite-type octahedral morphology with uniform size and good dispersion on the surface of CFC. SEM elemental mapping images confirm the good distribution of Ni, Fe, Se element on CFC. TEM and SAED provide the clear diffraction rings of octahedral Ni0.5Fe0.5Se2, which is consistent with the results of XRD. Furtherly, the effect of different ratio of Ni/Fe (NixFe1-xSe2 x = 0, 0.2, 0.5, 0.8, 1) on OER performances has been systematically investigated. The electrochemical measurements results show that Ni0.5Fe0.5Se2/CFC (x = 0.5) possesses the better electrocatalytic activity with the lower overpotential, Tafel slope and long-term stability than other samples. The enhanced activity of Ni0.5Fe0.5Se2/CFC may be attributed to the intrinsic activity of binary Ni0.5Fe0.5Se2 and faster electron transfer rate derived from CFC support.