Enhanced Oxygen Evolution\nReaction Electrocatalysis\nvia Electrodeposited Amorphous α‑Phase Nickel-Cobalt\nHydroxide Nanodendrite Forests

Abstract

We demonstrate an\nelectrodeposition method to rapidly grow novel\nthree-dimensional nanodendrite forests of amorphous α-phase\nmixed nickel-cobalt hydroxides on stainless steel foil toward high\nperformance electrocatalysis of the oxygen evolution reaction (OER).\nThe proposed hydrogen bubble-templated, diffusion-limited deposition\nprocess leads to the unprecedented dendritic growth of vertically\naligned amorphous metal hydroxides, induced by the controlled electrolysis\nof the tuned water content in the primarily alcohol-based deposition\nsolution. The hierarchical nature of these binder-free, amorphous\nmetal hydroxide deposits leads to their superhydrophilic nature and\nunderwater superaerophobic behavior. The combination of all of these\nqualities leads to exemplary catalytic performance. When directly\ngrown on planar stainless steel substrates, these nanoforests show\nhigh OER activity with overpotentials as low as ∼255 mV to\nproduce a current density of 10 mA cm^–2 over 10 000\naccelerated stability test cycles. This work demonstrates a novel\nfabrication technique that can simultaneously achieve a dendritic\nhierarchical structure, vertical alignment, superaerophobicity, amorphous\ncrystal structure, and intimate contact with the substrate that leads\nto high catalytic activity with excellent durability.