Hydrogen Evolution Reaction on Iridium-Modified Nickel Foam Surfaces

Abstract

This work reports on cathodic hydrogen evolution reaction (HER), studied on Ir-activated nickel foam materials, prepared through spontaneous and electrodeposition methods (examined in 0.1 M NaOH electrolyte). Both Ir modifications of Ni foam caused substantial improvement of the HER kinetics, as compared with those recorded for as-received and surface-activated nickel foam materials. Electrochemical examinations were conducted through AC impedance spectroscopy and quasi-steady-state cathodic polarization experiments. Significance of catalytic nature of Ir deposit and employed deposition methodology on the HER behavior of such-obtained Ni foam/Ir composites were discussed in detail by means of SEM/EDX spectroscopy analysis.

Interfacial Electronic Interactions Between Ultrathin NiFe‐MOF Nanosheets and Ir Nanoparticles Heterojunctions Leading to Efficient Overall Water Splitting

“…The ultrathin nanosheet structure of NiFe‐MOF, along with the immobilized oxygen atoms on the surface, not only hindered Ir NPs aggregation but also provided an abundance of electrochemically active sites, contributing to improved HER/OER kinetics [ 21 ] An interplanar spacing of 0.216 nm, corresponding to the (111) crystal plane of cubic Ir, confirmed the presence of Ir NPs (Figure 1g ). [ 22 ] Moreover, the corresponding high‐resolution EDS mappings demonstrated the even distribution of Ni, Fe, Ir, C, and O elements (Figure 1h ), which implies that Ir NPs grow uniformly on the NiFe‐MOF surface.…”