Modulating the Interlayer Microenvironment of Nickel Hydroxide Nanoarrays with Aromatic Carboxylates for Enhanced Oxygen Evolution Reaction

Single-metal hydroxides, which are low-cost and readily synthesized, exhibit a well-defined crystalline structure, rendering them an ideal model system for mechanistic studies of the oxygen evolution reaction (OER) in alkaline environments. The unique organic-inorganic hybrid interactions between metal hydroxide layers and aromatic carboxylate species have been demonstrated to enhance electrocatalytic OER activity by effectively modulating electronic and interfacial characteristics. The precise engineering of the local microenvironment is achieved through the intercalation of aromatic dicarboxylates with systematically varied conjugation lengths into the two-dimensional interlayers of Ni(OH)₂ nanoarrays (Ni(OH)₂ NAs). Experimental results demonstrate that this intercalation strategy preserves the morphological integrity of pristine "agaric-like" Ni(OH)₂ NAs while significantly enhancing the OER performance. Notably, the Ni(OH)₂ NAs intercalated with the longest π-conjugated spacer achieve an exceptionally low overpotential of 187 mV at a current density of 10 mA cm^-2, highlighting the critical role of interlayer architecture in determining catalytic efficiency.