Abstract:
A new hybrid catalyst based on Ni foam (NF) and FeSe was prepared by a facial hydrothermal method, in which Se-decorated NF was subsequently electrochemically doped by Fe. Binder-free catalyst containing electrodes were directly tested for the hydrogen and oxygen evolution reaction (HER/OER). The FeSe/NF electrode displayed an OER current density of 100 mA cm(-2) at potential of 1.42 V, and a relatively small Tafel slope of 109 mV dec(-1) in a 1 M KOH solution. Also, FeSe/NF electrode exhibited reasonable HER overpotential of 200 mV at 10 mAcm(-2) current density with Tafel slope of 145 mV dec(-1). The XRD and TEM studies revealed that the formation of heterogeneous interfaces of NiSe2 and FeSe2, generated more active sites that can promote better ions and electron transport in the electrode/electrolyte interfaces. Furthermore, HRTEM analysis indicates that FeSe2 rich in Se vacancy defects can be created with suitable M - O and M - H bond for better OER and HER performance, respectively. In a-two electrode alkaline water electrolyzer, current densities of 10 mA cm(-2) and 50 mA cm(-2) were obtained at cell voltages of 1.52 V and 1.85 V, respectively, using pure FeSe-NF as both the cathode and anode. (C) 2020 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.