Controllable synthesis of CoFe2Se4/NiCo2Se4 hybrid nanotubes with heterointerfaces and improved oxygen evolution
Huan Wang1, Zhonghua Sun, Xiaoran Zou
1College of Chemistry, Chemical Engineering and Materials Science, Collaborative Innovation Center of Functionalized Probes for Chemical Imaging in Universities of Shandong, Key Laboratory of Molecular and Nano Probes, Ministry of Education, Shandong Provincial Key Laboratory of Clean Production of Fine Chemicals, Shandong Normal University, Jinan 250014, China. cyzhang@sdnu.edu.cn.
Abstract:
The rational construction of heterointerfaces in hollow nanohybrids is considered as a promising and challenging approach for enhancing their electrocatalytic performance. Herein, we demonstrate the synthesis of CoFe2Se4/NiCo2Se4 hybrid nanotubes (CFSe/NCSe HNTs) with open ends and abundant heterointerfaces. The CFSe/NCSe HNT hybrid nanotubes are obtained by using NiCo2-aspartic acid nanofibres (NiCo-Asp NFs) as the templates which can be converted to the CFSe/NCSe HNTs via proton etching, three metal coprecipitation, Kirkendall effect and anion-exchange reaction. The CFSe/NCSe HNTs may function as the oxygen evolution reaction (OER) electrocatalysts, and they exhibit a low overpotential of 224 mV at a current density of 10 mA cm-2 and outstanding stability with only 1.4% current density change even after 15 h, superior to those of the reported single-component counterparts. The obtained density of states and differential charge density confirm the existence of a heterointerface which can induce the accumulation of electrons at the interface of CFSe-NCSe and consequently increase the carrier density and electrical conductivity of the CFSe/NCSe HNTs. This research provides a new avenue for the fabrication of hollow nanohybrids with heterointerfaces.
