“…Consequently, extensive research efforts have been focused on developing alternative water electrolysis catalysts based on transition metal compounds, such as perovskite oxides, , carbides, nitrides, phosphides, and sulfides . Additionally, layered double hydroxides (LDHs), which are two-dimensional materials with layered structures, have been recognized as excellent catalysts owing to their relatively large surface area and anion exchange ability. , The introduction of highly oxidized transition metal ions into LDHs has a synergistic effect on the catalytic activity of OER. − However, LDHs suffer from low electrical conductivity and weak structural stability, owing to the presence of anions and water molecules between their layers. − To overcome these drawbacks, transition metals have been combined with carbon nanostructures to produce systems such as NiFe-graphene, , NiCo-graphene, and NiFe-carbon nanotubes . The electrical conductivity limit has been improved through the hierarchical growth of an LDH structure on a precious metal framework with excellent conductivity .…”