Structure Effects of 2D Materials on α-Nickel Hydroxide for Oxygen Evolution Reaction

Abstract

To engineer low-cost, high-efficiency, and stable oxygen evolution reaction (OER) catalysts, structure effects should be primarily understood. Focusing on this, we systematically investigated the relationship between structures of materials and their OER performances by taking four 2D α-Ni(OH) as model materials, including layer-stacked bud-like Ni(OH)-NB, flower-like Ni(OH)-NF, and petal-like Ni(OH)-NP as well as the ultralarge sheet-like Ni(OH)-NS. For the first three (layer-stacking) catalysts, with the decrease of stacked layers, their accessible surface areas, abilities to adsorb OH, diffusion properties, and the intrinsic activities of active sites increase, which accounts for their steadily enhanced activity. As expected, Ni(OH)-NP shows the lowest overpotential (260 mV at 10 mA cm) and Tafel slope (78.6 mV dec) with a robust stability over 10 h among the samples, which also outperforms the benchmark IrO (360 mV and 115.8 mV dec) catalyst. Interestingly, Ni(OH)-NS relative to Ni(OH)-NP exhibits even faster substance diffusion due to the sheet-like structure, but shows inferior OER activity, which is mainly because the Ni(OH)-NP with a smaller size possesses more active boundary sites (higher reactivity of active sites) than Ni(OH)-NS, considering the adsorption properties and accessible surface areas of the two samples are quite similar. By comparing the different structures and their OER behaviors of four α-Ni(OH) samples, our work may shed some light on the structure effect of 2D materials and accelerate the development of efficient OER catalysts.

Dispersing transition metal vacancies in layered double hydroxides by ionic reductive complexation extraction for efficient water oxidation

“…The overpotential at 10 mA cm À2 , which is the approximate j for a 10% efficiency solar-to-fuel conversion device, was 290 mV, 289 mV, 343 mV, 347 mV, and 389 mV for SAV-NiCu x LDH, NiCu(I) LDH, NiCu LDH, Ni(OH) 2 and Ni foam, respectively (Fig. S13 †) with the prepared SAV-NiCu x LDH and NiCu(I) LDH showing the most smaller overpotentials that were even smaller than those of noble-metal catalysts of IrO 2 (350 mV) [42][43][44][45] and RuO 2 (365 mV) 46,47 (Fig. S14 †).…”

Synthesis of nickel hydroxide/reduced graphene oxide composite thin films for water splitting application

“…19 However, it shows low electrochemical performance due to its poor electronic conductivity and a small number of active sites. 20 To improve the electrocatalytic performance, various strategies are used such as doping the transition metals such as V, Fe, Co, 3,17,18 or hybridizing the conductive substrate using carbon nanotube, 21 and graphene derivatives. 22,23 For instance, the V doped Ni(OH) 2 nanostructure was prepared using the chemical bath deposition technique, which showed enhanced OER performance with overpotential of 268 mV @10 mA cm −2 .…”

Studying the Effect of CuCo2S4 Morphology on the Oxygen Evolution Reaction using a Flexible Carbon Cloth Substrate

“…The spherical, hollow and polyhedral Co 3 Mo 3 N was also used as a catalysis for OER, owing to the active sites on the inner and outer surfaces. The ultra‐thin Ni(OH) 2 and CoFe 2 O 4 nanosheets can also produce high performance catalysis, because of the rich marginal active sites. The ordered arrays were helpful to the electron transfer in the catalytic reaction .…”