Interfacial engineering design for one-dimensional cobalt-iron selenide nanomaterials as a high-efficiency catalyst for oxygen evolution reaction

One promising approach to improving the slow reaction dynamics of alkaline oxygen evolution reaction (OER) is to construct non-precious metal-based heterojunctions via interface engineering. In this work, the relationship between structure and activity for one-dimensional CoSe2/FeSe2 nanomaterials for OER is discussed in detail by experimental techniques, coupled with the density functional theory calculations. Capitalizing on the refined electronic structure layout and abundant heterogeneous interfaces, the hierarchical branched CoSe2/FeSe2 heterojunctions demonstrate the outstanding electrocatalytic activity for OER in 1 M KOH solution, and can achieve low overpotentials of 283 and 330 mV at current densities of 10 and 100 mA cm-2, respectively, as well as keeping 94.7 % of its initial activity after 100 h cycles. Furthermore, it is found that the enhanced inherent catalytic performance of CoSe2/FeSe2 electrocatalyst after standardizing the current density with electrochemically active surface area (ECSA) could be attributed to the robust interaction at the interface induced by the construction of the heterojunctions. This work presents the significance of manipulating the electronic structure of electrocatalysts utilizing interface design to enhance OER catalytic activity, and provides new insights for exploring the highly active electrocatalysts.