Facile synthesis of pyrite-type binary nickel iron diselenides as efficient electrocatalyst for oxygen evolution reaction

By Chi, Jing-Qi; Shang, Xiao; Liang, Fei; Dong, Bin; Li, Xiao; Liu, Yan-Ru; Yan, Kai-Li; Gao, Wen-Kun; Chai, Yong-Ming; Liu, Chen-Guang
Published in Applied Surface Science NULL 2017

Abstract

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.

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